linting

.forgejo/workflows/ci.yaml

@@ -63,6 +63,13 @@ jobs:
       - name: Bootstrap (build.sh)
         run: ./build.sh
 
+      # Full style gate: Report() findings (naming, enum-class, char*, …) AND
+      # would-reformat findings from the transform rules. A dirty tree means
+      # someone skipped `crafter-build format` — fail fast, before the
+      # (much slower) test suite.
+      - name: Lint
+        run: CRAFTER_BUILD_HOME=$PWD/share/crafter-build ./bin/crafter-build lint
+
       - name: Run tests
         run: CRAFTER_BUILD_HOME=$PWD/share/crafter-build ./bin/crafter-build test
 

README.md

@@ -245,6 +245,67 @@ extern "C" Configuration CrafterBuildProject(std::span<const std::string_view>)
 
 `ParentLib(name)` walks the parent project's dependency graph (and the parent itself) to find a `Configuration*` by `Configuration::name`. The build links it into the test exe, so `import MyLib;` resolves naturally. See [examples/tests/](examples/tests/) for the complete worked example.
 
+## Linting & formatting
+
+Lint rules are C++ in `project.cpp` — no `.lintrc`, no YAML, and no built-in rules. A rule is a named callback that runs once per source file; register it on the `Configuration` before returning:
+
+```cpp
+cfg.AddLintRule("no-tabs", [](Crafter::LintContext& ctx) {
+    if (ctx.Extension() != ".cpp" && ctx.Extension() != ".cppm") return;
+    for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {
+        if (ctx.Line(n).contains('\t')) ctx.Report(n, "tab character (use spaces)");
+    }
+});
+```
+
+A rule that calls `ctx.SetContent(newContent)` is a **transform** — defined once, it powers both verbs: `lint` reports where the transform would change the file (dry, never writes), and `format` applies it to disk:
+
+```cpp
+cfg.AddLintRule("final-newline", [](Crafter::LintContext& ctx) {
+    if (!ctx.content.empty() && !ctx.content.ends_with('\n')) {
+        ctx.SetContent(ctx.content + '\n');
+    }
+});
+```
+
+```bash
+crafter-build lint            # full dry gate: Report() findings + would-reformat, exit 1 on any
+crafter-build lint 'spdx*'    # rule-name glob filter
+crafter-build lint --list     # enumerate rules without running them
+crafter-build format          # apply transforms, rewrite changed files in place (exit 0)
+crafter-build format --check  # CI gate: list files that would change, exit 1 if any
+```
+
+Lint findings print compiler-style — `file:line: warning: message [rule]` — so editors and CI pick them up. `format` rewrites files in place (gofmt convention) and only touches files whose bytes actually change; report-only findings are `lint`'s business and don't affect `format`'s exit code. A project with no rules registered exits 1 with a message showing how to add one.
+
+`LintContext` gives each rule:
+
+| Member | Meaning |
+|---|---|
+| `file` | absolute path of the file under lint |
+| `content` | the whole file |
+| `lines` | pre-split line views (report 1-based via `Line(n)`) |
+| `Extension()` | file extension, e.g. `".cppm"` |
+| `CommentStripped()` | `content` with comments and string/char literal bodies blanked to spaces — newlines kept, so line numbers stay valid (raw strings not recognized yet) |
+| `Report(line, msg)` | record a finding (`line == 0` for whole-file) |
+| `SetContent(str)` | replace the file's content — makes the rule a transform; `lines` re-splits, `CommentStripped()` re-derives. Build the new string, call once at the end; don't assign `content` directly |
+
+Suppression is comment-based :
+
+```cpp
+// lint-disable-next-line no-char-pointer      — one rule, the following line
+// lint-disable-next-line naming, wrap-join    — several rules (space- or comma-separated)
+// lint-disable-next-line                      — all rules, the following line
+// lint-disable-file fixed-width-types         — one rule, whole file (any position)
+// lint-disable-file                           — all rules, whole file
+```
+
+Directives silence findings **and** stop `format` from rewriting the suppressed lines. The driver handles this automatically for reports and line-preserving transforms; a custom transform that merges or splits lines must ask `ctx.Suppressed(rule, line)` for the lines it touches (the built-in house rules do).
+
+The linted file set is the project's own sources: module interfaces (+ partitions), implementations, `cFiles`, `cuda`, shader sources, declared tests' sources, and `project.cpp` itself — for the root `Configuration` plus every transitive dependency whose path lies inside the project root. `GitProject` / external dependencies are foreign code and are skipped, as are `files`/`buildFiles`/`assets` (data, not source). Rules registered on any in-root config are collected and deduplicated by name, so with a lib/exe split you can attach them to either. Rules run in registration order, each seeing the previous transform's output; a rule that throws is reverted and becomes a finding instead of aborting the run. Files are read and written as bytes — line views carry a trailing `\r` on CRLF files, so transforms that should be CRLF-safe must handle it (see the `trim-trailing-ws` dogfood rule).
+
+This repo dogfoods the feature with its full house style — 15 rules in [lint-rules.h](lint-rules.h) (naming conventions, K&R braces, `enum class`, `std::println`, fixed-width integer types, `std::format` over concatenation, wrap-joining, whitespace hygiene), registered by [project.cpp](project.cpp) via one `ProjectLint::AddProjectLintRules(cfg)` call. The header is deliberately project-local, not part of the crafter-build library — copy it into a sibling repo to adopt the same style there; `tests/HouseRules/` validates every transform. Most rules are transforms: `crafter-build format` mechanically restyled this entire codebase (~150 fixes), with only expression rewrites the operand scanner can't prove safe (ternaries, raw-string lines) reported for hand-fixing.
+
 ## Examples
 
 [examples/](examples/) contains progressively larger self-contained projects:
@@ -260,7 +321,7 @@ Each builds standalone: `cd examples/<name> && crafter-build`.
 
 ## Architecture
 
-- **Modules**: `Crafter.Build:Shader` / `:Platform` / `:Interface` / `:Implementation` / `:External` / `:Clang` / `:Test` partitions, re-exported by the `Crafter.Build` umbrella.
+- **Modules**: `Crafter.Build:Shader` / `:Platform` / `:Interface` / `:Implementation` / `:External` / `:Clang` / `:Test` / `:Lint` / `:Progress` / `:Asset` partitions, re-exported by the `Crafter.Build` umbrella.
 - **Build process**: parallel — interface PCMs, implementation `.o` files, external dep clones, dep-config recursive builds, and shader compilations all spawn threads, sync at well-defined join points.
 - **`LoadProject`** compiles `project.cpp` to a shared object (`.so` on Linux, `.dll` on Windows) and loads it. On Linux the host exe is linked with `-Wl,--export-dynamic` so the project's undefined symbols resolve back into the running binary. On Windows the host is split into `crafter-build.dll` (everything) + a thin `crafter-build.exe` launcher; the public `Crafter::*` API is annotated with a `CRAFTER_API` macro (`__declspec(dllexport)` when the host is built, `__declspec(dllimport)` when project.dll consumes it via the rebuilt user-cache PCMs), and the host passes `-Wl,/EXPORT:CrafterBuildProject` when linking project.dll so user `project.cpp` files don't need platform-gated annotations.
 

build.cmd

@@ -18,6 +18,7 @@ copy /Y interfaces\Crafter.Build-Implementation.cppm share\crafter-build\
 copy /Y interfaces\Crafter.Build-External.cppm share\crafter-build\
 copy /Y interfaces\Crafter.Build-Clang.cppm share\crafter-build\
 copy /Y interfaces\Crafter.Build-Test.cppm share\crafter-build\
+copy /Y interfaces\Crafter.Build-Lint.cppm share\crafter-build\
 copy /Y interfaces\Crafter.Build-Progress.cppm share\crafter-build\
 copy /Y interfaces\Crafter.Build-Asset.cppm share\crafter-build\
 copy /Y interfaces\Crafter.Build-Api.h share\crafter-build\
@@ -57,6 +58,7 @@ clang++ %common_options% -fmodule-output interfaces\Crafter.Build-Implementation
 clang++ %common_options% -fmodule-output interfaces\Crafter.Build-External.cppm -o .\build\Crafter.Build-External.o
 clang++ %common_options% -fmodule-output interfaces\Crafter.Build-Clang.cppm -o .\build\Crafter.Build-Clang.o
 clang++ %common_options% -fmodule-output interfaces\Crafter.Build-Test.cppm -o .\build\Crafter.Build-Test.o
+clang++ %common_options% -fmodule-output interfaces\Crafter.Build-Lint.cppm -o .\build\Crafter.Build-Lint.o
 clang++ %common_options% -fmodule-output interfaces\Crafter.Build-Progress.cppm -o .\build\Crafter.Build-Progress.o
 REM Asset partition: bootstrap compiles it WITHOUT CRAFTER_BUILD_HAS_ASSET so
 REM CompressAsset takes the stub branch (no Crafter.Asset PCM exists yet).
@@ -70,6 +72,7 @@ clang++ %common_options% .\implementations\Crafter.Build-Implementation.cpp -o .
 clang++ %common_options% .\implementations\Crafter.Build-External.cpp -o .\build\Crafter.Build-External_impl.o
 clang++ %common_options% .\implementations\Crafter.Build-Clang.cpp -o .\build\Crafter.Build-Clang_impl.o
 clang++ %common_options% .\implementations\Crafter.Build-Test.cpp -o .\build\Crafter.Build-Test_impl.o
+clang++ %common_options% .\implementations\Crafter.Build-Lint.cpp -o .\build\Crafter.Build-Lint_impl.o
 clang++ %common_options% .\implementations\Crafter.Build-Progress.cpp -o .\build\Crafter.Build-Progress_impl.o
 clang++ %common_options% .\implementations\Crafter.Build-Asset.cpp -o .\build\Crafter.Build-Asset_impl.o
 clang++ %common_options% .\implementations\main.cpp -o .\build\main.o
@@ -85,6 +88,7 @@ clang++ %useLibcLinker% -shared -std=c++26 -O3 -march=%CRAFTER_BUILD_MARCH% -mtu
     .\build\Crafter.Build-External.o ^
     .\build\Crafter.Build-Clang.o ^
     .\build\Crafter.Build-Test.o ^
+    .\build\Crafter.Build-Lint.o ^
     .\build\Crafter.Build-Progress.o ^
     .\build\Crafter.Build-Asset.o ^
     .\build\Crafter.Build.o ^
@@ -95,6 +99,7 @@ clang++ %useLibcLinker% -shared -std=c++26 -O3 -march=%CRAFTER_BUILD_MARCH% -mtu
     .\build\Crafter.Build-External_impl.o ^
     .\build\Crafter.Build-Clang_impl.o ^
     .\build\Crafter.Build-Test_impl.o ^
+    .\build\Crafter.Build-Lint_impl.o ^
     .\build\Crafter.Build-Progress_impl.o ^
     .\build\Crafter.Build-Asset_impl.o ^
     -o .\bin\crafter-build.dll
@@ -114,6 +119,7 @@ llvm-lib.exe /OUT:.\lib\crafter-build-static.lib ^
     .\build\Crafter.Build-External.o ^
     .\build\Crafter.Build-Clang.o ^
     .\build\Crafter.Build-Test.o ^
+    .\build\Crafter.Build-Lint.o ^
     .\build\Crafter.Build-Progress.o ^
     .\build\Crafter.Build-Asset.o ^
     .\build\Crafter.Build.o ^
@@ -124,6 +130,7 @@ llvm-lib.exe /OUT:.\lib\crafter-build-static.lib ^
     .\build\Crafter.Build-External_impl.o ^
     .\build\Crafter.Build-Clang_impl.o ^
     .\build\Crafter.Build-Test_impl.o ^
+    .\build\Crafter.Build-Lint_impl.o ^
     .\build\Crafter.Build-Progress_impl.o ^
     .\build\Crafter.Build-Asset_impl.o
 

build.sh

@@ -18,6 +18,7 @@ cp interfaces/Crafter.Build-Implementation.cppm share/crafter-build/
 cp interfaces/Crafter.Build-External.cppm share/crafter-build/
 cp interfaces/Crafter.Build-Clang.cppm share/crafter-build/
 cp interfaces/Crafter.Build-Test.cppm share/crafter-build/
+cp interfaces/Crafter.Build-Lint.cppm share/crafter-build/
 cp interfaces/Crafter.Build-Progress.cppm share/crafter-build/
 cp interfaces/Crafter.Build-Asset.cppm share/crafter-build/
 cp interfaces/Crafter.Build-Api.h share/crafter-build/
@@ -55,6 +56,7 @@ clang++ $common_options -fmodule-output interfaces/Crafter.Build-Implementation.
 clang++ $common_options -fmodule-output interfaces/Crafter.Build-External.cppm -o ./build/Crafter.Build-External.o
 clang++ $common_options -fmodule-output interfaces/Crafter.Build-Clang.cppm -o ./build/Crafter.Build-Clang.o
 clang++ $common_options -fmodule-output interfaces/Crafter.Build-Test.cppm -o ./build/Crafter.Build-Test.o
+clang++ $common_options -fmodule-output interfaces/Crafter.Build-Lint.cppm -o ./build/Crafter.Build-Lint.o
 clang++ $common_options -fmodule-output interfaces/Crafter.Build-Progress.cppm -o ./build/Crafter.Build-Progress.o
 # Asset partition: bootstrap compiles it WITHOUT CRAFTER_BUILD_HAS_ASSET so
 # CompressAsset takes the stub branch and the impl unit doesn't try to
@@ -70,6 +72,7 @@ clang++ $common_options ./implementations/Crafter.Build-Implementation.cpp -o ./
 clang++ $common_options ./implementations/Crafter.Build-External.cpp -o ./build/Crafter.Build-External_impl.o
 clang++ $common_options ./implementations/Crafter.Build-Clang.cpp -o ./build/Crafter.Build-Clang_impl.o
 clang++ $common_options ./implementations/Crafter.Build-Test.cpp -o ./build/Crafter.Build-Test_impl.o
+clang++ $common_options ./implementations/Crafter.Build-Lint.cpp -o ./build/Crafter.Build-Lint_impl.o
 clang++ $common_options ./implementations/Crafter.Build-Progress.cpp -o ./build/Crafter.Build-Progress_impl.o
 clang++ $common_options ./implementations/Crafter.Build-Asset.cpp -o ./build/Crafter.Build-Asset_impl.o
 clang++ $common_options ./implementations/main.cpp -o ./build/main.o
@@ -82,6 +85,7 @@ ar rcs ./lib/libcrafter-build.a \
     ./build/Crafter.Build-External.o \
     ./build/Crafter.Build-Clang.o \
     ./build/Crafter.Build-Test.o \
+    ./build/Crafter.Build-Lint.o \
     ./build/Crafter.Build-Progress.o \
     ./build/Crafter.Build-Asset.o \
     ./build/Crafter.Build.o \
@@ -92,6 +96,7 @@ ar rcs ./lib/libcrafter-build.a \
     ./build/Crafter.Build-External_impl.o \
     ./build/Crafter.Build-Clang_impl.o \
     ./build/Crafter.Build-Test_impl.o \
+    ./build/Crafter.Build-Lint_impl.o \
     ./build/Crafter.Build-Progress_impl.o \
     ./build/Crafter.Build-Asset_impl.o
 
@@ -105,6 +110,7 @@ clang++ -std=c++26 -stdlib=libc++ -O3 -march=$MARCH -mtune=$MTUNE -fuse-ld=lld \
     ./build/Crafter.Build-External.o \
     ./build/Crafter.Build-Clang.o \
     ./build/Crafter.Build-Test.o \
+    ./build/Crafter.Build-Lint.o \
     ./build/Crafter.Build-Progress.o \
     ./build/Crafter.Build-Asset.o \
     ./build/Crafter.Build.o \
@@ -115,6 +121,7 @@ clang++ -std=c++26 -stdlib=libc++ -O3 -march=$MARCH -mtune=$MTUNE -fuse-ld=lld \
     ./build/Crafter.Build-External_impl.o \
     ./build/Crafter.Build-Clang_impl.o \
     ./build/Crafter.Build-Test_impl.o \
+    ./build/Crafter.Build-Lint_impl.o \
     ./build/Crafter.Build-Progress_impl.o \
     ./build/Crafter.Build-Asset_impl.o \
     ./build/main.o \

examples/hello-world/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 

examples/hello-world/project.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;

examples/library/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import MyMath;

examples/library/mylib/MyMath.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 export module MyMath;
 import std;

examples/library/project.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;

examples/tests/mylib/MyMath.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 export module MyMath;
 import std;

examples/tests/project.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;

examples/tests/tests/Smoke/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 // Single-file test: no project.cpp needed. The folder name "Smoke" becomes
 // the test name. Exit 0 = pass, anything else = fail, exit 77 = skipped.

examples/tests/tests/UnitMyMath/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import MyMath;

examples/wasi/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 

examples/wasi/project.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;

examples/with-module/interfaces/Greeter.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 export module Greeter;
 import std;

examples/with-module/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Greeter;

examples/with-module/project.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: MIT
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;

implementations/Crafter.Build-Asset.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module Crafter.Build:Asset_impl;
 import :Asset;
@@ -15,7 +15,7 @@ namespace Crafter {
         std::string ext = input.extension().string();
         // Case-insensitive extension match — Sponza's textures dir mixes
         // case (.tga and .TGA both appear in the wild).
-        for (char& c : ext) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+        for (char& c : ext) c = static_cast<char>(std::tolower(static_cast<std::uint8_t>(c)));
 #ifdef CRAFTER_BUILD_HAS_ASSET
         try {
             // stb_image (the loader behind LoadPNG) handles all of these,
@@ -35,20 +35,11 @@ namespace Crafter {
         }
         return {};
 #else
-        return std::format(
+        return std::format("{}: crafter-build was bootstrapped without Crafter.Asset linkage; " "rebuild via `./bin/crafter-build` so the self-host pass picks up the " "Crafter.Asset dep declared in project.cpp", input.string());
-            "{}: crafter-build was bootstrapped without Crafter.Asset linkage; "
-            "rebuild via `./bin/crafter-build` so the self-host pass picks up the "
-            "Crafter.Asset dep declared in project.cpp",
-            input.string());
 #endif
     }
 
-    std::string BuildOBJBundle(
+    std::string BuildOBJBundle(const fs::path& objPath, const fs::path& mtlPath, const fs::path& outDir, std::uint16_t   albedoSize) {
-        const fs::path& objPath,
-        const fs::path& mtlPath,
-        const fs::path& outDir,
-        std::uint16_t   albedoSize)
-    {
 #ifdef CRAFTER_BUILD_HAS_ASSET
         const fs::path manifest = outDir / "scene.txt";
         if (fs::exists(manifest)) return {};
@@ -75,9 +66,7 @@ namespace Crafter {
                 if (mesh.vertexes.empty() || mesh.indexes.empty()) continue;
                 mesh.SaveCompressed(outDir / std::format("mesh_{}.cmesh", emitted));
                 std::int32_t a = -1;
-                if (auto it = materials.find(matName);
+                if (auto it = materials.find(matName); it != materials.end() && !it->second.mapKd.empty()) a = static_cast<std::int32_t>(albedoIndex.at(it->second.mapKd));
-                    it != materials.end() && !it->second.mapKd.empty())
-                    a = static_cast<std::int32_t>(albedoIndex.at(it->second.mapKd));
                 meshAlbedoIdx.push_back(a);
                 ++emitted;
             }

implementations/Crafter.Build-Clang.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #if defined(CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_pc_windows_msvc) || defined(CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_w64_mingw32)
@@ -18,6 +18,7 @@ import std;
 import :Clang;
 import :Platform;
 import :Test;
+import :Lint;
 import :Progress;
 import :Asset;
 namespace fs = std::filesystem;
@@ -25,9 +26,7 @@ using namespace Crafter;
 
 
 void Configuration::GetInterfacesAndImplementations(std::span<fs::path> interfaces, std::span<fs::path> implementations) {
-    auto resolveImport = [this](const std::string& importName,
+    auto resolveImport = [this](const std::string& importName, std::vector<Module*>& localDeps, std::vector<std::pair<Module*, fs::path>>& externalDeps) -> bool {
-                                std::vector<Module*>& localDeps,
-                                std::vector<std::pair<Module*, fs::path>>& externalDeps) -> bool {
         for(const std::unique_ptr<Module>& interface : this->interfaces) {
             if(interface->name == importName) {
                 localDeps.push_back(interface.get());
@@ -40,7 +39,7 @@ void Configuration::GetInterfacesAndImplementations(std::span<fs::path> interfac
             if (!seen.insert(depCfg).second) return false;
             for(const std::unique_ptr<Module>& depInterface : depCfg->interfaces) {
                 if(depInterface->name == importName) {
-                    fs::path depPcmPath = (depCfg->PcmDir() / depInterface->path.filename()).string() + ".pcm";
+                    fs::path depPcmPath = std::format("{}.pcm", (depCfg->PcmDir() / depInterface->path.filename()).string());
                     externalDeps.emplace_back(depInterface.get(), std::move(depPcmPath));
                     return true;
                 }
@@ -305,7 +304,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
     // a single thread to match the cfg.files pattern.
     auto compressedName = [](const fs::path& src) -> std::optional<fs::path> {
         std::string ext = src.extension().string();
-        for (char& c : ext) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+        for (char& c : ext) c = static_cast<char>(std::tolower(static_cast<std::uint8_t>(c)));
         // stb_image (used by CompressAsset → TextureAsset::LoadPNG) handles
         // png/tga/jpg/bmp; all map to .ctex.
         if (ext == ".png" || ext == ".tga" || ext == ".jpg" || ext == ".jpeg" || ext == ".bmp") {
@@ -435,7 +434,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
     // it with extra codegen flags (e.g. -mrelaxed-simd) — its BMI must not be
     // shared with the baseline's, or the consuming TUs see a target-feature
     // mismatch. Suffix the cache dir with the variant flags when present.
-    std::string stdPcmKey = config.target + "-" + config.march;
+    std::string stdPcmKey = std::format("{}-{}", config.target, config.march);
     for (const std::string& f : config.wasmVariantFlags) {
         stdPcmKey += "+";
         for (char c : f) stdPcmKey += (c == '/' || c == '\\') ? '_' : c;
@@ -492,7 +491,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
         // for the baseline build. Part of VariantId, so these objects/PCMs
         // land in their own dir.
         for (const std::string& f : config.wasmVariantFlags) {
-            command += " " + f;
+            command += std::format(" {}", f);
         }
     }
     if (config.target == "x86_64-w64-mingw32") {
@@ -542,7 +541,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
             if (!seen.insert(dep).second) return;
             for (const auto& entry : fs::recursive_directory_iterator(dep->path)) {
                 if (entry.is_directory() && entry.path().filename() == "include") {
-                    includeFlags += " -I" + entry.path().string();
+                    includeFlags += std::format(" -I{}", entry.path().string());
                 }
             }
             includeFlags += std::format(" -I{}", dep->path.string());
@@ -629,7 +628,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
     // pick them up too (vendored C deps usually need -I from this set).
     std::string userFlags;
     for(const std::string& flag : config.compileFlags) {
-        userFlags += " " + flag;
+        userFlags += std::format(" {}", flag);
     }
     command += userFlags;
 
@@ -676,8 +675,8 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
     }
     for (const fs::path& cFile : config.cFiles) {
         files += std::format(" {}_source.o ", (buildDir / cFile.filename()).string());
-        const std::string objPath = (buildDir / cFile.filename()).string() + "_source.o";
+        const std::string objPath = std::format("{}_source.o", (buildDir / cFile.filename()).string());
-        const std::string srcPath = cFile.string() + ".c";
+        const std::string srcPath = std::format("{}.c", cFile.string());
         if (!fs::exists(objPath) || (fs::exists(srcPath) && fs::last_write_time(srcPath) > fs::last_write_time(objPath))) {
             threads.emplace_back([&cFile, &buildDir, &buildError, &buildCancelled, &config, &includeFlags, &defineFlags, &userFlags, &cArchFlags, &ltoCompileFlags]() {
                 Progress::Task task(std::format("Compiling {}.c", cFile.filename().string()));
@@ -696,8 +695,8 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
 
     for (const fs::path& cFile : config.cuda) {
         files += std::format(" {}_source.o ", (buildDir / cFile.filename()).string());
-        const std::string objPath = (buildDir / cFile.filename()).string() + "_source.o";
+        const std::string objPath = std::format("{}_source.o", (buildDir / cFile.filename()).string());
-        const std::string srcPath = cFile.string() + ".cu";
+        const std::string srcPath = std::format("{}.cu", cFile.string());
         if (!fs::exists(objPath) || (fs::exists(srcPath) && fs::last_write_time(srcPath) > fs::last_write_time(objPath))) {
             threads.emplace_back([&cFile, &buildDir, &buildError, &buildCancelled]() {
                 Progress::Task task(std::format("Compiling {}.cu", cFile.filename().string()));
@@ -789,7 +788,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
                         continue;
                     }
                     std::string ext = asset.extension().string();
-                    for (char& c : ext) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+                    for (char& c : ext) c = static_cast<char>(std::tolower(static_cast<std::uint8_t>(c)));
                     fs::path srcName = asset.filename();
                     if (ext == ".png" || ext == ".tga" || ext == ".jpg" || ext == ".jpeg" || ext == ".bmp") {
                         srcName.replace_extension(".ctex");
@@ -821,12 +820,12 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
     // Public compile flags propagated from sub-deps. Add them to this build's
     // command so config sees the headers its deps expose, and re-publish them
     // so config's own consumers see them transitively.
-    for (const std::string& flag : publicFlagSet) command += " " + flag;
+    for (const std::string& flag : publicFlagSet) command += std::format(" {}", flag);
     buildResult.publicCompileFlags = std::move(publicFlagSet);
     fs::file_time_type externalFloor = fs::file_time_type::min();
     for(const ExternalBuildResult& ext : externalResults) {
         for(const std::string& flag : ext.compileFlags) {
-            command += " " + flag;
+            command += std::format(" {}", flag);
             // Headers a dep links via ExternalDependency are part of its
             // public surface (its modules can include them in declarations
             // visible to consumers), so propagate the -I to consumers.
@@ -889,7 +888,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
 
     std::string linkExtras;
     for(const std::string& flag : buildResult.libs) {
-        linkExtras += " " + flag;
+        linkExtras += std::format(" {}", flag);
     }
     // Link-only LTO/section flags (empty in Debug and for wasm). Every exe/lib
     // link below ends with linkExtras, so this reaches them all; the static-lib
@@ -927,10 +926,9 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
         auto expectedOutputFor = [](const Configuration& c) -> fs::path {
             fs::path dir = c.BinDir();
             if (c.type == ConfigurationType::Executable) {
-                if (c.target.starts_with("wasm32"))
+                if (c.target.starts_with("wasm32")) return dir / (std::format("{}.wasm", c.outputName));
-                    return dir / (c.outputName + ".wasm");
                 return c.target == "x86_64-w64-mingw32"
-                    ? dir / (c.outputName + ".exe")
+                    ? dir / (std::format("{}.exe", c.outputName))
                     : dir / c.outputName;
             }
             if (c.type == ConfigurationType::LibraryStatic) {
@@ -971,13 +969,13 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
                     return !ec && t > consumerMtime;
                 };
                 for (const std::unique_ptr<Module>& iface : config.interfaces) {
-                    if (objNewer(buildDir / (iface->path.filename().string() + ".o"))) {
+                    if (objNewer(buildDir / std::format("{}.o", iface->path.filename().string()))) {
                         buildResult.repack = true;
                         break;
                     }
                     bool partHit = false;
                     for (const std::unique_ptr<ModulePartition>& part : iface->partitions) {
-                        if (objNewer(buildDir / (part->path.filename().string() + ".o"))) {
+                        if (objNewer(buildDir / std::format("{}.o", part->path.filename().string()))) {
                             partHit = true;
                             break;
                         }
@@ -986,7 +984,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
                 }
                 if (!buildResult.repack) {
                     for (const Implementation& impl : config.implementations) {
-                        if (objNewer(buildDir / (impl.path.filename().string() + "_impl.o"))) {
+                        if (objNewer(buildDir / std::format("{}_impl.o", impl.path.filename().string()))) {
                             buildResult.repack = true;
                             break;
                         }
@@ -1016,8 +1014,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
                             // import lib (so a downstream `crafter-build.exe`
                             // can link a fresh project.dll against it without
                             // hunting through sibling output dirs).
-                            for (auto fname : {std::format("{}.dll", dep->outputName),
+                            for (auto fname : {std::format("{}.dll", dep->outputName), std::format("lib{}.dll.a", dep->outputName)}) {
-                                               std::format("lib{}.dll.a", dep->outputName)}) {
                                 fs::path src = depDir / fname;
                                 if (!fs::exists(src)) continue;
                                 fs::path dest = outputDir / src.filename();
@@ -1053,8 +1050,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
                     if (!dllSeen.insert(dep).second) return;
                     if (dep->type == ConfigurationType::LibraryDynamic && dep->target == "x86_64-w64-mingw32") {
                         fs::path depDir = dep->BinDir();
-                        for (auto fname : {std::format("{}.dll", dep->outputName),
+                        for (auto fname : {std::format("{}.dll", dep->outputName), std::format("lib{}.dll.a", dep->outputName)}) {
-                                           std::format("lib{}.dll.a", dep->outputName)}) {
                             fs::path src = depDir / fname;
                             if (!fs::exists(src)) continue;
                             fs::path dest = outputDir / src.filename();
@@ -1067,9 +1063,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
                 };
                 for (Configuration* dep : config.dependencies) copyDepDlls(dep);
 
-                buildResult.result = RunCommand(std::format(
+                buildResult.result = RunCommand(std::format("{}{} -o {} -fuse-ld=lld{}", command, files, (outputDir/config.outputName).string(), linkExtras));
-                    "{}{} -o {} -fuse-ld=lld{}",
-                    command, files, (outputDir/config.outputName).string(), linkExtras));
             } else {
                 std::system(std::format("copy \"%LIBCXX_DIR%\\lib\\c++.dll\" \"{}\\c++.dll\"", outputDir.string()).c_str());
                 buildResult.result = RunCommand(std::format("{}{} -o {}.exe -fuse-ld=lld -L %LIBCXX_DIR%\\lib -lc++ -nostdinc++ -nostdlib++{}", command, files, (outputDir/config.outputName).string(), linkExtras));
@@ -1095,19 +1089,13 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
             if (config.target == "x86_64-w64-mingw32") {
                 fs::path dll = outputDir / std::format("{}.dll", config.outputName);
                 fs::path implib = outputDir / std::format("lib{}.dll.a", config.outputName);
-                buildResult.result = RunCommand(std::format(
+                buildResult.result = RunCommand(std::format("{}{} -shared -o {} -Wl,--out-implib,{} -fuse-ld=lld{}", command, files, dll.string(), implib.string(), linkExtras));
-                    "{}{} -shared -o {} -Wl,--out-implib,{} -fuse-ld=lld{}",
-                    command, files, dll.string(), implib.string(), linkExtras));
             } else if (config.target == "x86_64-pc-windows-msvc") {
                 fs::path dll = outputDir / std::format("{}.dll", config.outputName);
                 fs::path implib = outputDir / std::format("{}.lib", config.outputName);
-                buildResult.result = RunCommand(std::format(
+                buildResult.result = RunCommand(std::format("{}{} -shared -o {} -Wl,/IMPLIB:{} -fuse-ld=lld{}", command, files, dll.string(), implib.string(), linkExtras));
-                    "{}{} -shared -o {} -Wl,/IMPLIB:{} -fuse-ld=lld{}",
-                    command, files, dll.string(), implib.string(), linkExtras));
             } else {
-                buildResult.result = RunCommand(std::format(
+                buildResult.result = RunCommand(std::format("{}{} -shared -o {}.so -Wl,-rpath,'$ORIGIN' -fuse-ld=lld{}", command, files, (outputDir/(std::string("lib")+config.outputName)).string(), linkExtras));
-                    "{}{} -shared -o {}.so -Wl,-rpath,'$ORIGIN' -fuse-ld=lld{}",
-                    command, files, (outputDir/(std::string("lib")+config.outputName)).string(), linkExtras));
             }
         }
     }
@@ -1127,11 +1115,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
     // Guard: only fires on the top-level config that *declared* wasmVariants
     // (deps leave it empty) and never on a variant pass itself (those carry
     // wasmVariantFlags), so there's no recursion. Skipped on build error.
-    if (buildResult.result.empty()
+    if (buildResult.result.empty() && config.target.starts_with("wasm32") && config.type == ConfigurationType::Executable && !config.wasmVariants.empty() && config.wasmVariantFlags.empty()) {
-            && config.target.starts_with("wasm32")
-            && config.type == ConfigurationType::Executable
-            && !config.wasmVariants.empty()
-            && config.wasmVariantFlags.empty()) {
         fs::path baselineBin = config.BinDir();
 
         // The whole transitive graph, so the variant flags reach every TU.
@@ -1151,8 +1135,7 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
             // another name — nothing extra to compile.
             if (variant.label.empty() || variant.flags.empty()) continue;
 
-            Progress::Task task(std::format("Building wasm variant {} ({})",
+            Progress::Task task(std::format("Building wasm variant {} ({})", variant.label, config.outputName));
-                                            variant.label, config.outputName));
 
             for (Configuration* c : graph) c->wasmVariantFlags = variant.flags;
             fs::path variantBin = config.BinDir();
@@ -1164,19 +1147,16 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
             for (Configuration* c : graph) c->wasmVariantFlags.clear();
 
             if (!vr.result.empty()) {
-                buildResult.result = std::format(
+                buildResult.result = std::format("wasm variant '{}' build failed: {}", variant.label, vr.result);
-                    "wasm variant '{}' build failed: {}", variant.label, vr.result);
                 break;
             }
 
             std::error_code ec;
-            fs::path src = variantBin / (config.outputName + ".wasm");
+            fs::path src = variantBin / (std::format("{}.wasm", config.outputName));
             fs::path dst = baselineBin / std::format("{}.{}.wasm", config.outputName, variant.label);
             fs::copy_file(src, dst, fs::copy_options::overwrite_existing, ec);
             if (ec) {
-                buildResult.result = std::format(
+                buildResult.result = std::format("copy wasm variant '{}' {} -> {}: {}", variant.label, src.string(), dst.string(), ec.message());
-                    "copy wasm variant '{}' {} -> {}: {}",
-                    variant.label, src.string(), dst.string(), ec.message());
                 break;
             }
         }
@@ -1190,9 +1170,7 @@ void Crafter::EnableWasiBrowserRuntime(Configuration& cfg) {
     fs::path runtimeJs = runtimeDir / "runtime.js";
     fs::path htmlTemplate = runtimeDir / "index.html.in";
     if (!fs::exists(runtimeJs) || !fs::exists(htmlTemplate)) {
-        throw std::runtime_error(std::format(
+        throw std::runtime_error(std::format("wasi-runtime assets missing under {} (set CRAFTER_BUILD_HOME or reinstall)", runtimeDir.string()));
-            "wasi-runtime assets missing under {} (set CRAFTER_BUILD_HOME or reinstall)",
-            runtimeDir.string()));
     }
 
     fs::path htmlOutDir = cfg.path / "build" / "wasi-runtime" / cfg.name;
@@ -1225,15 +1203,11 @@ void Crafter::EnableWasiBrowserRuntime(Configuration& cfg) {
     // the dev server (python -m http.server) sends no Cache-Control
     // headers. Using ms-since-epoch is enough to be unique per build
     // without invoking any version-control machinery.
-    const std::string buildId = std::to_string(
+    const std::string buildId = std::to_string(std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now().time_since_epoch()).count());
-        std::chrono::duration_cast<std::chrono::milliseconds>(
-            std::chrono::system_clock::now().time_since_epoch()).count());
 
     std::string envScriptTags;
     for (const std::string& name : envScripts) {
-        envScriptTags += std::format(
+        envScriptTags += std::format("        <script src=\"{}?v={}\" type=\"module\"></script>\n", name, buildId);
-            "        <script src=\"{}?v={}\" type=\"module\"></script>\n",
-            name, buildId);
     }
 
     // Walk the dep graph again for non-JS assets — these get pre-loaded by
@@ -1250,7 +1224,7 @@ void Crafter::EnableWasiBrowserRuntime(Configuration& cfg) {
     // one preloaded wins. Avoid collisions in the source tree.
     auto compressedExt = [](const fs::path& src) -> std::optional<std::string> {
         std::string ext = src.extension().string();
-        for (char& c : ext) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+        for (char& c : ext) c = static_cast<char>(std::tolower(static_cast<std::uint8_t>(c)));
         if (ext == ".png" || ext == ".tga" || ext == ".jpg" || ext == ".jpeg" || ext == ".bmp") {
             return std::string(".ctex");
         }
@@ -1340,7 +1314,7 @@ void Crafter::EnableWasiBrowserRuntime(Configuration& cfg) {
             if (!first) v << ",";
             first = false;
             std::string url = label.empty()
-                ? cfg.outputName + ".wasm"
+                ? std::format("{}.wasm", cfg.outputName)
                 : std::format("{}.{}.wasm", cfg.outputName, label);
             v << "{\"label\":\"" << jsonEscape(label) << "\""
               << ",\"url\":\"" << jsonEscape(url) << "\""
@@ -1363,7 +1337,7 @@ void Crafter::EnableWasiBrowserRuntime(Configuration& cfg) {
     std::stringstream buf;
     buf << in.rdbuf();
     std::string html = buf.str();
-    html = std::regex_replace(html, std::regex(R"(\{\{WASM\}\})"), cfg.outputName + ".wasm");
+    html = std::regex_replace(html, std::regex(R"(\{\{WASM\}\})"), std::format("{}.wasm", cfg.outputName));
     html = std::regex_replace(html, std::regex(R"(\{\{ENV_SCRIPTS\}\})"), envScriptTags);
     html = std::regex_replace(html, std::regex(R"(\{\{BUILDID\}\})"), buildId);
     std::ofstream out(htmlPath);
@@ -1388,14 +1362,14 @@ void Crafter::EnableWasiRelaxedSimdVariant(Configuration& cfg) {
 }
 
 std::string Crafter::HostTarget() {
-    static const std::string cached = []() -> std::string {
+    static const std::string Cached = []() -> std::string {
         CommandResult r = RunCommandChecked("clang++ -print-target-triple");
         if (r.exitCode != 0) return {};
         std::string out = std::move(r.output);
         while (!out.empty() && (out.back() == '\n' || out.back() == '\r')) out.pop_back();
         return out;
     }();
-    return cached;
+    return Cached;
 }
 
 bool Crafter::ArgQuery::Has(std::string_view flag) const {
@@ -1417,7 +1391,8 @@ ArgQuery Crafter::ApplyStandardArgs(Configuration& cfg, std::span<const std::str
     if (const char* envMtune = std::getenv("CRAFTER_BUILD_MTUNE"); envMtune && *envMtune) {
         cfg.mtune = envMtune;
     }
-    bool sawLib = false, sawShared = false;
+    bool sawLib = false;
+    bool sawShared = false;
     for (std::string_view a : args) {
         if (a == "--debug") cfg.debug = true;
         else if (a == "--lib") sawLib = true;
@@ -1446,6 +1421,8 @@ static void PrintHelp(std::string_view argv0) {
 R"(Usage:
   {0} [options] [-- project-args...]    Build the project in the current directory
   {0} test [test-options] [globs...]    Build and run the project's tests
+  {0} lint [lint-options] [globs...]    Run the project's lint rules over its sources
+  {0} format [format-options] [globs...]  Apply the project's transform rules (rewrites files)
   {0} help | -h | --help                Show this help
 
 Loads ./project.cpp (override with --project=<path>), compiles it to a shared
@@ -1472,6 +1449,22 @@ Test options (after the `test` subcommand):
                             project's tests plus the host triple.
   <glob>                    One or more name globs to filter tests (e.g. 'Unit*').
 
+Lint options (after the `lint` subcommand):
+  --list                    Enumerate matching lint rules without running them.
+  <glob>                    One or more name globs to filter rules (e.g. 'spdx*').
+
+  Lint rules are defined in project.cpp via cfg.AddLintRule(name, callback) —
+  C++ callbacks run once per source file. No rules ship by default.
+
+Format options (after the `format` subcommand):
+  --check                   Dry run: list files that would change, exit 1 if any.
+  --list                    Enumerate matching rules without running them.
+  <glob>                    One or more name globs to filter rules.
+
+  Rules are shared with lint — a rule that calls ctx.SetContent is a
+  transform. `format` rewrites changed files in place; `lint` reports the
+  same transforms as would-reformat findings without writing.
+
 Project args:
   Any flag not consumed above is forwarded verbatim to CrafterBuildProject as
   part of its `args` span. Project-specific flags (e.g. --target=, custom
@@ -1487,8 +1480,9 @@ Environment:
   LIBCXX_DIR                           Windows libc++ install (MSVC ABI builds).
 
 Exit status:
-  0  success / all non-skipped tests passed
+  0  success / all non-skipped tests passed / lint clean / format applied
-  1  build failure or one or more tests failed
+  1  build failure, one or more tests failed, lint findings, no rules defined,
+     format write errors, or `format --check` found files that would change
 )", argv0);
 }
 
@@ -1500,17 +1494,27 @@ int Crafter::Run(int argc, char** argv) {
         projectArgs.reserve(argc);
 
         bool runTests = false;
+        bool runLint = false;
+        bool runFormat = false;
         bool runAfterBuild = false;
         RunTestsOptions testOpts;
+        RunLintOptions lintOpts;
         Progress::Verbosity verbosity = Progress::Verbosity::Default;
 
         for (int i = 1; i < argc; ++i) {
             std::string_view arg = argv[i];
-            if (arg == "-h" || arg == "--help" || (!runTests && arg == "help")) {
+            if (arg == "-h" || arg == "--help" || (!runTests && !runLint && !runFormat && arg == "help")) {
                 PrintHelp(argv0);
                 return 0;
-            } else if (arg == "test") {
+            } else if (!runLint && !runFormat && arg == "test") {
                 runTests = true;
+            } else if (!runTests && !runFormat && arg == "lint") {
+                runLint = true;
+            } else if (!runTests && !runLint && arg == "format") {
+                runFormat = true;
+                lintOpts.mode = LintMode::Apply;
+            } else if (runFormat && arg == "--check") {
+                lintOpts.mode = LintMode::Check;
             } else if (arg == "-r") {
                 runAfterBuild = true;
             } else if (arg == "-v" || arg == "--verbose") {
@@ -1529,6 +1533,10 @@ int Crafter::Run(int argc, char** argv) {
                 testOpts.runnerOverride = std::string(arg.substr(std::string_view("--runner=").size()));
             } else if (runTests && !arg.starts_with("-")) {
                 testOpts.globs.emplace_back(arg);
+            } else if ((runLint || runFormat) && arg == "--list") {
+                lintOpts.listOnly = true;
+            } else if ((runLint || runFormat) && !arg.starts_with("-")) {
+                lintOpts.globs.emplace_back(arg);
             } else {
                 projectArgs.push_back(arg);
             }
@@ -1553,6 +1561,18 @@ int Crafter::Run(int argc, char** argv) {
         Configuration config = LoadProject(projectFile, projectArgs);
         SetParentProject(&config);
 
+        if (runLint || runFormat) {
+            // lexically_normal: fs::absolute keeps a "./" component, which
+            // would leak into displayed paths and the project-root derivation.
+            lintOpts.projectFile = fs::absolute(projectFile).lexically_normal();
+            LintSummary lintSummary = RunLint(config, lintOpts);
+            if (!runFormat) return lintSummary.Clean() ? 0 : 1;
+            if (lintSummary.noRulesDefined || lintSummary.errors > 0) return 1;
+            // Apply: formatting files is success (gofmt convention).
+            // Check: a would-change file is the CI failure signal.
+            return lintOpts.mode == LintMode::Check && !lintSummary.changedFiles.empty() ? 1 : 0;
+        }
+
         if (runTests) {
             TestSummary summary = RunTests(config, testOpts, projectArgs);
             return summary.AllPassed() ? 0 : 1;
@@ -1602,20 +1622,20 @@ int Crafter::Run(int argc, char** argv) {
                     // Probe-bind to find a free port starting at 8080 — if the
                     // user has another dev server running we shift up rather
                     // than letting caddy/python exit with EADDRINUSE.
-                    auto findFreePort = [](int basePort, int span) -> int {
+                    auto findFreePort = [](std::int32_t basePort, std::int32_t span) -> std::int32_t {
 #if defined(CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_pc_windows_msvc) || defined(CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_w64_mingw32)
-                        static const bool wsaInit = []{ WSADATA d; return WSAStartup(MAKEWORD(2, 2), &d) == 0; }();
+                        static const bool WsaInit = []{ WSADATA d; return WSAStartup(MAKEWORD(2, 2), &d) == 0; }();
-                        if (!wsaInit) return basePort;
+                        if (!WsaInit) return basePort;
-                        using sock_t = SOCKET;
+                        using Sock = SOCKET;
-                        const sock_t invalid = INVALID_SOCKET;
+                        const Sock invalid = INVALID_SOCKET;
-                        auto closesock = [](sock_t s){ closesocket(s); };
+                        auto closesock = [](Sock s){ closesocket(s); };
 #else
-                        using sock_t = int;
+                        using Sock = std::int32_t;
-                        const sock_t invalid = -1;
+                        const Sock invalid = -1;
-                        auto closesock = [](sock_t s){ ::close(s); };
+                        auto closesock = [](Sock s){ ::close(s); };
 #endif
-                        for (int p = basePort; p < basePort + span; ++p) {
+                        for (std::int32_t p = basePort; p < basePort + span; ++p) {
-                            sock_t s = ::socket(AF_INET, SOCK_STREAM, 0);
+                            Sock s = ::socket(AF_INET, SOCK_STREAM, 0);
                             if (s == invalid) return basePort;
                             sockaddr_in addr{};
                             addr.sin_family = AF_INET;
@@ -1627,7 +1647,7 @@ int Crafter::Run(int argc, char** argv) {
                         }
                         return basePort;
                     };
-                    const int port = findFreePort(8080, 16);
+                    const std::int32_t port = findFreePort(8080, 16);
                     // Cross-origin isolation: the browser coarsens
                     // performance.now() (and chrono::steady_clock under wasi)
                     // to ~0.1ms unless the response carries COOP/COEP, which
@@ -1661,8 +1681,7 @@ int Crafter::Run(int argc, char** argv) {
                             "    file_server\n"
                             "}}\n",
                             port, absDir.string()));
-                        cmd = std::format("caddy run --config {} --adapter caddyfile",
+                        cmd = std::format("caddy run --config {} --adapter caddyfile", cf.string());
-                                          cf.string());
                     } else if (have("python3") || have("python")) {
                         std::string_view py = have("python3") ? "python3" : "python";
                         picked = py;
@@ -1701,8 +1720,7 @@ int Crafter::Run(int argc, char** argv) {
                             "header('Cache-Control: no-store');\n"
                             "return false;\n");
                         isolated = true;
-                        cmd = std::format("php -S 0.0.0.0:{} -t {} {}",
+                        cmd = std::format("php -S 0.0.0.0:{} -t {} {}", port, absDir.string(), rp.string());
-                                          port, absDir.string(), rp.string());
                     } else if (have("ruby")) {
                         picked = "ruby";
                         cmd = std::format("ruby -run -e httpd {} -p{}", absDir.string(), port);
@@ -1713,17 +1731,12 @@ int Crafter::Run(int argc, char** argv) {
                         picked = "npx http-server";
                         cmd = std::format("npx --yes http-server {} -p {} --silent", absDir.string(), port);
                     } else {
-                        std::println(std::cerr,
+                        std::println(std::cerr, "-r wasm: no HTTP server found in PATH. Install one of: " "caddy, python3, python, php, ruby, busybox, npx (Node.js).");
-                            "-r wasm: no HTTP server found in PATH. Install one of: "
-                            "caddy, python3, python, php, ruby, busybox, npx (Node.js).");
                         return 1;
                     }
                     std::println("listening on port :{}", port);
                     if (!isolated) {
-                        std::println(std::cerr,
+                        std::println(std::cerr, "warning: {} does not emit COOP/COEP — performance.now() will be coarse " "(~0.1ms). Install caddy, python3, or php for cross-origin isolation.", picked);
-                            "warning: {} does not emit COOP/COEP — performance.now() will be coarse "
-                            "(~0.1ms). Install caddy, python3, or php for cross-origin isolation.",
-                            picked);
                     }
                     // Silence the backend's own banner/request logs so the
                     // experience is identical regardless of which server is
@@ -1742,9 +1755,7 @@ int Crafter::Run(int argc, char** argv) {
                 if (have("wasmer")) {
                     return std::system(std::format("wasmer run {}", artifact.string()).c_str()) == 0 ? 0 : 1;
                 }
-                std::println(std::cerr,
+                std::println(std::cerr, "-r wasm: no wasm runtime found in PATH. Install wasmtime or wasmer, " "or call EnableWasiBrowserRuntime(cfg) in project.cpp for a browser build.");
-                    "-r wasm: no wasm runtime found in PATH. Install wasmtime or wasmer, "
-                    "or call EnableWasiBrowserRuntime(cfg) in project.cpp for a browser build.");
                 return 1;
             }
 

implementations/Crafter.Build-External.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module Crafter.Build:External_impl;
 import std;
@@ -175,10 +175,7 @@ std::string ConfigureCMake(const fs::path& cloneDir, const fs::path& cmakeBuildD
 
     if (!fs::exists(cmakeBuildDir)) fs::create_directories(cmakeBuildDir);
 
-    std::string cmd = std::format("cmake -S {} -B {}{}",
+    std::string cmd = std::format("cmake -S {} -B {}{}", ShellQuote(fs::absolute(cloneDir).string()), ShellQuote(fs::absolute(cmakeBuildDir).string()), BuildInjectedCMakeFlags(cmakeBuildDir, target));
-        ShellQuote(fs::absolute(cloneDir).string()),
-        ShellQuote(fs::absolute(cmakeBuildDir).string()),
-        BuildInjectedCMakeFlags(cmakeBuildDir, target));
     if (!options.empty()) {
         cmd += " ";
         cmd += optionsKey;
@@ -198,9 +195,8 @@ std::string BuildCMake(const fs::path& cmakeBuildDir) {
     // unit at a time, leaving every core but one idle. Pass an explicit job
     // count (a bare --parallel maps to an unbounded `make -j` fork bomb on the
     // Makefiles generator) so deps like DPP/msquic/glslang compile ~N× faster.
-    unsigned jobs = std::max(1u, std::thread::hardware_concurrency());
+    std::uint32_t jobs = std::max(1u, std::thread::hardware_concurrency());
-    std::string cmd = std::format("cmake --build {} --parallel {}",
+    std::string cmd = std::format("cmake --build {} --parallel {}", ShellQuote(fs::absolute(cmakeBuildDir).string()), jobs);
-        ShellQuote(fs::absolute(cmakeBuildDir).string()), jobs);
     CommandResult r = RunCommandChecked(cmd);
     if (r.exitCode != 0) {
         return std::format("cmake --build failed (exit {}): {}", r.exitCode, r.output);
@@ -210,10 +206,7 @@ std::string BuildCMake(const fs::path& cmakeBuildDir) {
 
 }  // namespace
 
-ExternalBuildResult Crafter::BuildExternal(
+ExternalBuildResult Crafter::BuildExternal(const ExternalDependency& dep, std::string_view target, std::atomic<bool>& cancelled) {
-        const ExternalDependency& dep,
-        std::string_view target,
-        std::atomic<bool>& cancelled) {
     ExternalBuildResult result;
 
     if (cancelled.load(std::memory_order_relaxed)) return result;
@@ -234,8 +227,7 @@ ExternalBuildResult Crafter::BuildExternal(
         }
     }
 
-    std::string keyMaterial = std::format("{}|{}|{}|{}|{}",
+    std::string keyMaterial = std::format("{}|{}|{}|{}|{}", dep.source.url, dep.source.branch, dep.source.commit, JoinOptions(dep.options), target);
-        dep.source.url, dep.source.branch, dep.source.commit, JoinOptions(dep.options), target);
     std::size_t key = std::hash<std::string>{}(keyMaterial);
     fs::path cloneDir = externalRoot / std::format("{}-{:016x}", name, key);
 
@@ -303,8 +295,8 @@ ExternalBuildResult Crafter::BuildExternal(
 }
 
 namespace {
-    std::mutex projectCacheMutex;
+    std::mutex ProjectCacheMutex;
-    std::unordered_map<std::string, std::unique_ptr<Configuration>> projectCache;
+    std::unordered_map<std::string, std::unique_ptr<Configuration>> ProjectCache;
 
     // Run the dep's project.cpp from its own directory so its relative paths
     // (cfg.path = "./", interfaces/, lib/, ...) resolve against the dep
@@ -342,8 +334,7 @@ Configuration* Crafter::GitProject(const GitProjectSpec& spec) {
     // how the dep's project.cpp interprets them at runtime), while the
     // in-memory Configuration is keyed by the full spec so each (args)
     // permutation gets its own Configuration object.
-    std::string srcKey = std::format("git|{}|{}|{}|{}",
+    std::string srcKey = std::format("git|{}|{}|{}|{}", spec.source.url, spec.source.branch, spec.source.commit, spec.projectFile.string());
-        spec.source.url, spec.source.branch, spec.source.commit, spec.projectFile.string());
     std::string srcHash = std::format("{:016x}", std::hash<std::string>{}(srcKey));
 
     std::string fullKey = srcKey;
@@ -354,8 +345,8 @@ Configuration* Crafter::GitProject(const GitProjectSpec& spec) {
     std::string fullHash = std::format("{:016x}", std::hash<std::string>{}(fullKey));
 
     {
-        std::lock_guard lock(projectCacheMutex);
+        std::lock_guard lock(ProjectCacheMutex);
-        if (auto it = projectCache.find(fullHash); it != projectCache.end()) {
+        if (auto it = ProjectCache.find(fullHash); it != ProjectCache.end()) {
             return it->second.get();
         }
     }
@@ -379,38 +370,34 @@ Configuration* Crafter::GitProject(const GitProjectSpec& spec) {
 
     fs::path projectPath = cloneDir / spec.projectFile;
     if (!fs::exists(projectPath)) {
-        throw std::runtime_error(std::format(
+        throw std::runtime_error(std::format("GitProject({}): {} not found in clone", spec.source.url, spec.projectFile.string()));
-            "GitProject({}): {} not found in clone", spec.source.url, spec.projectFile.string()));
     }
 
     std::vector<std::string_view> argViews(spec.args.begin(), spec.args.end());
     Configuration cfg = LoadProjectFromRoot(projectPath, cloneDir, argViews);
 
-    std::lock_guard lock(projectCacheMutex);
+    std::lock_guard lock(ProjectCacheMutex);
-    if (auto it = projectCache.find(fullHash); it != projectCache.end()) {
+    if (auto it = ProjectCache.find(fullHash); it != ProjectCache.end()) {
         return it->second.get();
     }
     auto stored = std::make_unique<Configuration>(std::move(cfg));
     Configuration* ptr = stored.get();
-    projectCache.emplace(std::move(fullHash), std::move(stored));
+    ProjectCache.emplace(std::move(fullHash), std::move(stored));
     return ptr;
 }
 
 fs::path Crafter::GitFetch(const GitSource& source) {
     std::string name = DeriveName(source);
     if (name.empty()) {
-        throw std::runtime_error(std::format(
+        throw std::runtime_error(std::format("GitFetch: could not derive name from URL '{}'", source.url));
-            "GitFetch: could not derive name from URL '{}'", source.url));
     }
     fs::path externalRoot = GetCacheDir() / "external";
     std::error_code ec;
     fs::create_directories(externalRoot, ec);
     if (ec) {
-        throw std::runtime_error(std::format(
+        throw std::runtime_error(std::format("GitFetch: failed to create {}: {}", externalRoot.string(), ec.message()));
-            "GitFetch: failed to create {}: {}", externalRoot.string(), ec.message()));
     }
-    std::string keyMaterial = std::format("git|{}|{}|{}",
+    std::string keyMaterial = std::format("git|{}|{}|{}", source.url, source.branch, source.commit);
-        source.url, source.branch, source.commit);
     std::size_t key = std::hash<std::string>{}(keyMaterial);
     fs::path cloneDir = externalRoot / std::format("{}-{:016x}", name, key);
 
@@ -439,8 +426,8 @@ Configuration* Crafter::LocalProject(const LocalProjectSpec& spec) {
     std::string fullHash = std::format("{:016x}", std::hash<std::string>{}(fullKey));
 
     {
-        std::lock_guard lock(projectCacheMutex);
+        std::lock_guard lock(ProjectCacheMutex);
-        if (auto it = projectCache.find(fullHash); it != projectCache.end()) {
+        if (auto it = ProjectCache.find(fullHash); it != ProjectCache.end()) {
             return it->second.get();
         }
     }
@@ -449,12 +436,12 @@ Configuration* Crafter::LocalProject(const LocalProjectSpec& spec) {
     std::vector<std::string_view> argViews(spec.args.begin(), spec.args.end());
     Configuration cfg = LoadProjectFromRoot(canonical, depRoot, argViews);
 
-    std::lock_guard lock(projectCacheMutex);
+    std::lock_guard lock(ProjectCacheMutex);
-    if (auto it = projectCache.find(fullHash); it != projectCache.end()) {
+    if (auto it = ProjectCache.find(fullHash); it != ProjectCache.end()) {
         return it->second.get();
     }
     auto stored = std::make_unique<Configuration>(std::move(cfg));
     Configuration* ptr = stored.get();
-    projectCache.emplace(std::move(fullHash), std::move(stored));
+    ProjectCache.emplace(std::move(fullHash), std::move(stored));
     return ptr;
 }

implementations/Crafter.Build-Implementation.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module Crafter.Build:Implementation_impl;
 import std;
@@ -13,8 +13,8 @@ namespace Crafter {
 
     }
     bool Implementation::Check(const fs::path& buildDir, const fs::path& pcmDir, fs::file_time_type sourceFloor) const {
-        std::string objPath = (buildDir/path.filename()).string()+"_impl.o";
+        std::string objPath = std::format("{}_impl.o", (buildDir/path.filename()).string());
-        std::string cppPath = path.string()+".cpp";
+        std::string cppPath = std::format("{}.cpp", path.string());
         if(!fs::exists(objPath) || std::max(fs::last_write_time(cppPath), sourceFloor) >= fs::last_write_time(objPath)) {
             return true;
         }

implementations/Crafter.Build-Interface.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module Crafter.Build:Interface_impl;
 import std;
@@ -13,8 +13,8 @@ namespace Crafter {
     bool ModulePartition::Check(const fs::path& pcmDir, fs::file_time_type sourceFloor) {
         if(!checked) {
             checked = true;
-            std::string pcmPath = (pcmDir/path.filename()).generic_string()+".pcm";
+            std::string pcmPath = std::format("{}.pcm", (pcmDir/path.filename()).generic_string());
-            std::string cppmPath = path.generic_string()+".cppm";
+            std::string cppmPath = std::format("{}.cppm", path.generic_string());
             if(fs::exists(pcmPath) && std::max(fs::last_write_time(cppmPath), sourceFloor) < fs::last_write_time(pcmPath)) {
                 fs::file_time_type pcmTime = fs::last_write_time(pcmPath);
                 for(ModulePartition* dependency : partitionDependencies) {
@@ -97,8 +97,8 @@ namespace Crafter {
     bool Module::Check(const fs::path& pcmDir, fs::file_time_type sourceFloor) {
         if(!checked) {
             checked = true;
-            std::string pcmPath = (pcmDir/path.filename()).generic_string()+".pcm";
+            std::string pcmPath = std::format("{}.pcm", (pcmDir/path.filename()).generic_string());
-            std::string cppmPath = path.generic_string()+".cppm";
+            std::string cppmPath = std::format("{}.cppm", path.generic_string());
             if(fs::exists(pcmPath) && std::max(fs::last_write_time(cppmPath), sourceFloor) < fs::last_write_time(pcmPath)) {
                 bool depCheck = false;
                 for(std::unique_ptr<ModulePartition>& partition : partitions) {

implementations/Crafter.Build-Lint.cpp

@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+
+module;
+export module Crafter.Build:Lint_impl;
+import std;
+import :Lint;
+import :Clang;
+import :Platform;
+import :Progress;
+namespace fs = std::filesystem;
+using namespace Crafter;
+
+namespace {
+    // Blank //-comments, /*...*/ comments and string/char literal bodies to
+    // spaces while copying '\n' through, so byte offsets and line numbers in
+    // the result match the original text. Raw string literals are not
+    // recognized (documented v1 limitation) — their bodies pass through as
+    // ordinary string content until the first '"'.
+    std::string StripComments(std::string_view src) {
+        enum class State { Code, LineComment, BlockComment, String, Char };
+        std::string out;
+        out.reserve(src.size());
+        State state = State::Code;
+        for (std::size_t i = 0; i < src.size(); ++i) {
+            char c = src[i];
+            char next = i + 1 < src.size() ? src[i + 1] : '\0';
+            switch (state) {
+                case State::Code:
+                    if (c == '/' && next == '/') {
+                        state = State::LineComment;
+                        out += "  ";
+                        ++i;
+                    } else if (c == '/' && next == '*') {
+                        state = State::BlockComment;
+                        out += "  ";
+                        ++i;
+                    } else if (c == '"') {
+                        state = State::String;
+                        out += c; // keep the delimiter so quoting stays visible
+                    } else if (c == '\'') {
+                        state = State::Char;
+                        out += c;
+                    } else {
+                        out += c;
+                    }
+                    break;
+                case State::LineComment:
+                    if (c == '\n') {
+                        state = State::Code;
+                        out += c;
+                    } else {
+                        out += ' ';
+                    }
+                    break;
+                case State::BlockComment:
+                    if (c == '*' && next == '/') {
+                        state = State::Code;
+                        out += "  ";
+                        ++i;
+                    } else {
+                        out += c == '\n' ? '\n' : ' ';
+                    }
+                    break;
+                case State::String:
+                case State::Char: {
+                    char delim = state == State::String ? '"' : '\'';
+                    if (c == '\\' && next != '\0') {
+                        out += "  ";
+                        ++i;
+                        if (next == '\n') out.back() = '\n';
+                    } else if (c == delim) {
+                        state = State::Code;
+                        out += c;
+                    } else {
+                        out += c == '\n' ? '\n' : ' ';
+                    }
+                    break;
+                }
+            }
+        }
+        return out;
+    }
+
+    std::vector<std::string_view> SplitLines(std::string_view content) {
+        std::vector<std::string_view> lines;
+        std::size_t start = 0;
+        while (start <= content.size()) {
+            std::size_t end = content.find('\n', start);
+            if (end == std::string_view::npos) {
+                // Skip a phantom empty final line after a trailing '\n'.
+                if (start < content.size()) lines.push_back(content.substr(start));
+                break;
+            }
+            lines.push_back(content.substr(start, end - start));
+            start = end + 1;
+        }
+        return lines;
+    }
+
+    bool PathInsideRoot(const fs::path& p, const fs::path& root) {
+        fs::path rel = fs::weakly_canonical(p).lexically_relative(fs::weakly_canonical(root));
+        return !rel.empty() && *rel.begin() != "..";
+    }
+
+    // Depth-first walk over the dependency graph keeping only Configurations
+    // whose path lies inside the project root — GitProject / external deps
+    // live under the global cache and are foreign code: they contribute
+    // neither rules nor files. Root-first order so the root's rules win the
+    // by-name dedup.
+    std::vector<Configuration*> CollectLocalConfigs(Configuration& root, const fs::path& projectRoot) {
+        std::vector<Configuration*> local;
+        std::unordered_set<Configuration*> seen;
+        std::function<void(Configuration*)> walk = [&](Configuration* c) {
+            if (!seen.insert(c).second) return;
+            if (PathInsideRoot(fs::absolute(c->path), projectRoot)) {
+                local.push_back(c);
+            }
+            for (Configuration* dep : c->dependencies) walk(dep);
+        };
+        walk(&root);
+        return local;
+    }
+
+    void CollectConfigSources(const Configuration& c, std::set<fs::path>& files) {
+        for (const std::unique_ptr<Module>& mod : c.interfaces) {
+            files.insert(fs::path(std::format("{}.cppm", mod->path.string())));
+            for (const std::unique_ptr<ModulePartition>& part : mod->partitions) {
+                files.insert(fs::path(std::format("{}.cppm", part->path.string())));
+            }
+        }
+        for (const Implementation& impl : c.implementations) {
+            files.insert(fs::path(std::format("{}.cpp", impl.path.string())));
+        }
+        // cFiles/cuda resolve against cwd at build time (see Build's compile
+        // loops); mirror that here.
+        for (const fs::path& cf : c.cFiles) {
+            files.insert(fs::absolute(fs::path(std::format("{}.c", cf.string()))).lexically_normal());
+        }
+        for (const fs::path& cu : c.cuda) {
+            files.insert(fs::absolute(fs::path(std::format("{}.cu", cu.string()))).lexically_normal());
+        }
+        for (const Shader& shader : c.shaders) {
+            files.insert(fs::absolute(shader.path).lexically_normal());
+        }
+        // files/buildFiles/assets are deliberately excluded: data shipped or
+        // referenced by the build, not source code.
+    }
+}
+
+std::string LintContext::Extension() const {
+    return file.extension().string();
+}
+
+std::string_view LintContext::Line(std::size_t n) const {
+    if (n == 0 || n > lines.size()) return {};
+    return lines[n - 1];
+}
+
+const std::string& LintContext::CommentStripped() {
+    if (!commentStrippedCache) {
+        commentStrippedCache = StripComments(content);
+    }
+    return *commentStrippedCache;
+}
+
+void LintContext::Report(std::size_t line, std::string message) {
+    sink->push_back({file, line, activeRule, std::move(message)});
+}
+
+namespace {
+    // Scan raw lines for suppression comments. Raw, not stripped: the
+    // directives ARE comments. A next-line directive on (0-based) line i
+    // targets 1-based line i + 2 — the line below it.
+    LintSuppressions ParseSuppressions(std::span<const std::string_view> lines) {
+        LintSuppressions s;
+        constexpr std::string_view NextLineMarker = "lint-disable-next-line";
+        constexpr std::string_view FileMarker = "lint-disable-file";
+        for (std::size_t i = 0; i < lines.size(); ++i) {
+            std::size_t slash = lines[i].find("//");
+            if (slash == std::string_view::npos) continue;
+            bool nextLine = true;
+            std::size_t marker = lines[i].find(NextLineMarker, slash);
+            std::size_t markerLen = NextLineMarker.size();
+            if (marker == std::string_view::npos) {
+                nextLine = false;
+                marker = lines[i].find(FileMarker, slash);
+                markerLen = FileMarker.size();
+            }
+            if (marker == std::string_view::npos) continue;
+            // Everything after the marker is rule names; none = all rules.
+            std::string_view rest = lines[i].substr(marker + markerLen);
+            std::vector<std::string> names;
+            std::size_t pos = 0;
+            while (pos < rest.size()) {
+                if (rest[pos] == ' ' || rest[pos] == '\t' || rest[pos] == ',' || rest[pos] == '\r') { ++pos; continue; }
+                std::size_t end = rest.find_first_of(" \t,\r", pos);
+                if (end == std::string_view::npos) end = rest.size();
+                names.emplace_back(rest.substr(pos, end - pos));
+                pos = end;
+            }
+            if (nextLine) {
+                if (names.empty()) s.lineAll.insert(i + 2);
+                else for (std::string& n : names) s.lineRules[i + 2].insert(std::move(n));
+            } else {
+                if (names.empty()) s.fileAll = true;
+                else for (std::string& n : names) s.fileRules.insert(std::move(n));
+            }
+        }
+        return s;
+    }
+}
+
+bool LintContext::Suppressed(std::string_view rule, std::size_t line) {
+    if (!suppressionsCache) suppressionsCache = ParseSuppressions(lines);
+    const LintSuppressions& s = *suppressionsCache;
+    if (s.fileAll || s.fileRules.contains(std::string(rule))) return true;
+    if (line == 0) return false;
+    if (s.lineAll.contains(line)) return true;
+    if (auto it = s.lineRules.find(line); it != s.lineRules.end()) return it->second.contains(std::string(rule));
+    return false;
+}
+
+void LintContext::SetContent(std::string newContent) {
+    content = std::move(newContent);
+    lines = SplitLines(content);
+    commentStrippedCache.reset();
+    suppressionsCache.reset(); // line numbers may have shifted — re-parse
+}
+
+void Configuration::AddLintRule(std::string name, std::function<void(LintContext&)> check) {
+    lintRules.push_back({std::move(name), std::move(check)});
+}
+
+LintSummary Crafter::RunLint(Configuration& projectCfg, const RunLintOptions& opts) {
+    LintSummary summary;
+
+    fs::path projectRoot = opts.projectFile.empty()
+        ? fs::absolute(projectCfg.path)
+        : opts.projectFile.parent_path();
+
+    std::vector<Configuration*> localConfigs = CollectLocalConfigs(projectCfg, projectRoot);
+
+    // Collect rules root-first, dedup by name (first registration wins).
+    std::vector<const LintRule*> rules;
+    std::unordered_set<std::string_view> ruleNames;
+    for (Configuration* c : localConfigs) {
+        for (const LintRule& rule : c->lintRules) {
+            if (ruleNames.insert(rule.name).second) rules.push_back(&rule);
+        }
+    }
+
+    if (rules.empty()) {
+        summary.noRulesDefined = true;
+        std::println(std::cerr,
+R"msg(No lint rules defined.
+Register rules in project.cpp before returning the Configuration:
+
+    cfg.AddLintRule("no-tabs", [](Crafter::LintContext& ctx) {{
+        if (ctx.Extension() != ".cpp" && ctx.Extension() != ".cppm") return;
+        for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {{
+            if (ctx.Line(n).contains('\t')) ctx.Report(n, "tab character (use spaces)");
+        }}
+    }});
+
+A rule that calls ctx.SetContent(newContent) is a transform: `crafter-build
+format` applies it to disk, and `crafter-build lint` reports where it would.
+`crafter-build lint` runs every rule over the project's own sources.)msg");
+        return summary;
+    }
+
+    std::erase_if(rules, [&](const LintRule* r) { return !MatchAny(opts.globs, r->name); });
+    summary.rulesRun = rules.size();
+
+    if (opts.listOnly) {
+        for (const LintRule* rule : rules) std::println("{}", rule->name);
+        return summary;
+    }
+    if (rules.empty()) {
+        std::println("No lint rules matched.");
+        return summary;
+    }
+
+    std::set<fs::path> files;
+    for (Configuration* c : localConfigs) {
+        CollectConfigSources(*c, files);
+        for (const Test& t : c->tests) CollectConfigSources(t.config, files);
+    }
+    if (!opts.projectFile.empty()) files.insert(opts.projectFile);
+
+    fs::path cwd = fs::current_path();
+    auto shown = [&cwd](const fs::path& p) {
+        return PathInsideRoot(p, cwd) ? p.lexically_relative(cwd) : p;
+    };
+
+    for (const fs::path& file : files) {
+        std::ifstream in(file, std::ios::binary);
+        if (!in) continue; // config parse already read it; a vanished file fails the build first
+        std::stringstream buffer;
+        buffer << in.rdbuf();
+        LintContext ctx;
+        ctx.file = file;
+        ctx.content = std::move(buffer).str();
+        ctx.lines = SplitLines(ctx.content);
+        ctx.sink = &summary.findings;
+        ++summary.filesLinted;
+        const std::string original = ctx.content;
+        for (const LintRule* rule : rules) {
+            ctx.activeRule = rule->name;
+            // Snapshot for transform diffing — and the revert point if the
+            // rule throws, so a half-applied transform never reaches disk
+            // and chained rules see clean input.
+            std::string before = ctx.content;
+            try {
+                rule->check(ctx);
+            } catch (const std::exception& e) {
+                // Never let a rule's exception unwind across the project
+                // DLL boundary — surface it as a finding instead.
+                ctx.SetContent(std::move(before));
+                ctx.Report(0, std::format("rule '{}' threw: {}", rule->name, e.what()));
+                ++summary.errors;
+                if (opts.mode != LintMode::Report) {
+                    // Report mode prints it with the findings; the other
+                    // modes don't print findings, so surface it here.
+                    std::println(std::cerr, "{}: rule '{}' threw: {}", shown(file).string(), rule->name, e.what());
+                }
+                continue;
+            }
+            // Transform detection is compare-by-value: a rule that SetContents
+            // identical bytes is not a change. The mutated content carries
+            // forward in every mode so chained rules compose identically
+            // whether or not this run writes.
+            if (ctx.content == before) continue;
+            // File-level suppression disables the transform outright — in
+            // every mode, so `format` never rewrites a suppressed file.
+            if (ctx.Suppressed(rule->name, 0)) {
+                ctx.SetContent(std::move(before));
+                continue;
+            }
+            // Diff before/after. Same line count → per-line handling:
+            // suppressed changed lines are REVERTED (all modes — suppression
+            // must also stop `format`), the rest yield would-reformat
+            // findings in the dry modes. Different count (or no differing
+            // line — SplitLines hides a trailing '\n', the final-newline
+            // case) → one whole-file finding; count-changing transforms
+            // handle per-line suppression themselves (see
+            // LintContext::Suppressed).
+            std::vector<std::string_view> beforeLines = SplitLines(before);
+            bool anyLineDiffers = false;
+            if (beforeLines.size() == ctx.lines.size()) {
+                std::vector<std::size_t> reverted;
+                for (std::size_t i = 0; i < beforeLines.size(); ++i) {
+                    if (beforeLines[i] == ctx.lines[i]) continue;
+                    anyLineDiffers = true;
+                    if (ctx.Suppressed(rule->name, i + 1)) {
+                        reverted.push_back(i);
+                    } else if (opts.mode != LintMode::Apply) {
+                        summary.findings.push_back({file, i + 1, rule->name, "would reformat"});
+                    }
+                }
+                if (!reverted.empty()) {
+                    std::string rebuilt;
+                    rebuilt.reserve(ctx.content.size());
+                    std::size_t next = 0;
+                    for (std::size_t i = 0; i < ctx.lines.size(); ++i) {
+                        rebuilt += (next < reverted.size() && reverted[next] == i) ? beforeLines[i] : ctx.lines[i];
+                        if (next < reverted.size() && reverted[next] == i) ++next;
+                        if (i + 1 < ctx.lines.size() || ctx.content.ends_with('\n')) rebuilt += '\n';
+                    }
+                    ctx.SetContent(std::move(rebuilt));
+                }
+            }
+            if (!anyLineDiffers && opts.mode != LintMode::Apply && ctx.content != before) {
+                summary.findings.push_back({file, 0, rule->name, "would reformat"});
+            }
+        }
+        // Drop findings the file's directives suppress — covers Report()
+        // calls from any rule (custom ones included) plus the derived
+        // would-reformat findings above. Line-0 findings only match
+        // file-level directives.
+        std::erase_if(summary.findings, [&](const LintFinding& f) {
+            return f.file == file && ctx.Suppressed(f.rule, f.line);
+        });
+        if (ctx.content != original) {
+            summary.changedFiles.push_back(file);
+            if (opts.mode == LintMode::Apply) {
+                std::ofstream out(file, std::ios::binary | std::ios::trunc);
+                out.write(ctx.content.data(), static_cast<std::streamsize>(ctx.content.size()));
+                out.close();
+                if (!out) {
+                    std::println(std::cerr, "failed to write {}", shown(file).string());
+                    ++summary.errors;
+                }
+            }
+        }
+    }
+
+    std::sort(summary.findings.begin(), summary.findings.end(),
+              [](const LintFinding& a, const LintFinding& b) {
+                  return std::tie(a.file, a.line) < std::tie(b.file, b.line);
+              });
+
+    Progress::Clear();
+    switch (opts.mode) {
+        case LintMode::Report: {
+            std::unordered_set<std::string> filesWithFindings;
+            for (const LintFinding& f : summary.findings) {
+                filesWithFindings.insert(f.file.string());
+                std::println("{}:{}: warning: {} [{}]", shown(f.file).string(), f.line, f.message, f.rule);
+            }
+            if (summary.findings.empty()) {
+                std::println("Lint clean: {} files, {} rules", summary.filesLinted, summary.rulesRun);
+            } else {
+                std::println("{} finding(s) in {} of {} files ({} rules)", summary.findings.size(), filesWithFindings.size(), summary.filesLinted, summary.rulesRun);
+            }
+            break;
+        }
+        case LintMode::Check: {
+            // gofmt -l style: the paths alone, then a one-line verdict.
+            // Report-only findings are lint's business, not printed here.
+            for (const fs::path& f : summary.changedFiles) {
+                std::println("{}", shown(f).string());
+            }
+            if (summary.changedFiles.empty()) {
+                std::println("Format check clean: {} files, {} rules", summary.filesLinted, summary.rulesRun);
+            } else {
+                std::println("{} file(s) would be reformatted", summary.changedFiles.size());
+            }
+            break;
+        }
+        case LintMode::Apply: {
+            for (const fs::path& f : summary.changedFiles) {
+                std::println("formatted: {}", shown(f).string());
+            }
+            if (summary.changedFiles.empty()) {
+                std::println("Nothing to format: {} files, {} rules", summary.filesLinted, summary.rulesRun);
+            } else {
+                std::println("Formatted {} of {} files ({} rules)", summary.changedFiles.size(), summary.filesLinted, summary.rulesRun);
+            }
+            break;
+        }
+    }
+    return summary;
+}

implementations/Crafter.Build-Platform.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #if defined(CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_pc_windows_msvc) || defined(CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_w64_mingw32)
@@ -42,7 +42,7 @@ namespace {
     // don't keep the lock alive past our own release.
     class CacheLock {
 #ifdef CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_pc_linux_gnu
-        int fd_ = -1;
+        std::int32_t fd_ = -1;
     public:
         explicit CacheLock(const fs::path& cacheDir) {
             fd_ = ::open((cacheDir / ".lock").c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 0644);
@@ -59,9 +59,7 @@ namespace {
         HANDLE handle_ = INVALID_HANDLE_VALUE;
     public:
         explicit CacheLock(const fs::path& cacheDir) {
-            handle_ = CreateFileW((cacheDir / ".lock").wstring().c_str(),
+            handle_ = CreateFileW((cacheDir / ".lock").wstring().c_str(), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);
-                GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE,
-                nullptr, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);
             if (handle_ != INVALID_HANDLE_VALUE) {
                 OVERLAPPED ov{};
                 LockFileEx(handle_, LOCKFILE_EXCLUSIVE_LOCK, 0, MAXDWORD, MAXDWORD, &ov);
@@ -111,15 +109,43 @@ fs::path Crafter::GetCrafterBuildHome() {
         if (parent == dir) break;
         dir = parent;
     }
-    std::string msg = std::format(
+    std::string msg = std::format("could not locate crafter-build runtime assets relative to {} (set CRAFTER_BUILD_HOME). Tried:", hostExe.string());
-        "could not locate crafter-build runtime assets relative to {} (set CRAFTER_BUILD_HOME). Tried:",
-        hostExe.string());
     for (const auto& p : tried) {
-        msg += "\n  " + p.string();
+        msg += std::format("\n  {}", p.string());
     }
     throw std::runtime_error(msg);
 }
 
+bool Crafter::MatchGlob(std::string_view glob, std::string_view name) {
+    std::size_t gi = 0;
+    std::size_t ni = 0;
+    std::size_t star = std::string_view::npos;
+    std::size_t mark = 0;
+    while (ni < name.size()) {
+        if (gi < glob.size() && (glob[gi] == '?' || glob[gi] == name[ni])) {
+            ++gi; ++ni;
+        } else if (gi < glob.size() && glob[gi] == '*') {
+            star = gi++;
+            mark = ni;
+        } else if (star != std::string_view::npos) {
+            gi = star + 1;
+            ni = ++mark;
+        } else {
+            return false;
+        }
+    }
+    while (gi < glob.size() && glob[gi] == '*') ++gi;
+    return gi == glob.size();
+}
+
+bool Crafter::MatchAny(std::span<const std::string> globs, std::string_view name) {
+    if (globs.empty()) return true;
+    for (const auto& g : globs) {
+        if (MatchGlob(g, name)) return true;
+    }
+    return false;
+}
+
 #if defined(CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_pc_windows_msvc) || defined(CRAFTER_BUILD_CONFIGURATION_TARGET_x86_64_w64_mingw32)
 std::string Crafter::RunCommand(const std::string_view cmd) {
     Progress::EchoCommand(cmd);
@@ -127,14 +153,14 @@ std::string Crafter::RunCommand(const std::string_view cmd) {
     std::string result;
 
     // Use cmd.exe to interpret redirection
-    std::string with = "cmd /C \"" + std::string(cmd) + " 2>&1\"";
+    std::string with = std::format("cmd /C \"{} 2>&1\"", std::string(cmd));
 
     FILE* pipe = _popen(with.c_str(), "r");
     if (!pipe) {
         throw std::runtime_error("_popen() failed!");
     }
 
-    while (fgets(buffer.data(), static_cast<int>(buffer.size()), pipe) != nullptr) {
+    while (fgets(buffer.data(), static_cast<std::int32_t>(buffer.size()), pipe) != nullptr) {
         result += buffer.data();
     }
 
@@ -146,14 +172,14 @@ CommandResult Crafter::RunCommandChecked(std::string_view cmd) {
     std::array<char, 128> buffer;
     CommandResult result{};
 
-    std::string with = "cmd /C \"" + std::string(cmd) + " 2>&1\"";
+    std::string with = std::format("cmd /C \"{} 2>&1\"", std::string(cmd));
 
     FILE* pipe = _popen(with.c_str(), "r");
     if (!pipe) {
         throw std::runtime_error("_popen() failed!");
     }
 
-    while (fgets(buffer.data(), static_cast<int>(buffer.size()), pipe) != nullptr) {
+    while (fgets(buffer.data(), static_cast<std::int32_t>(buffer.size()), pipe) != nullptr) {
         result.output += buffer.data();
     }
 
@@ -165,7 +191,8 @@ CommandResult Crafter::RunCommandWithTimeout(std::string_view cmd, std::chrono::
     CommandResult result{};
 
     SECURITY_ATTRIBUTES sa{ sizeof(sa), nullptr, TRUE };
-    HANDLE readEnd = nullptr, writeEnd = nullptr;
+    HANDLE readEnd = nullptr;
+    HANDLE writeEnd = nullptr;
     if (!CreatePipe(&readEnd, &writeEnd, &sa, 0)) {
         throw std::runtime_error("CreatePipe failed");
     }
@@ -196,14 +223,11 @@ CommandResult Crafter::RunCommandWithTimeout(std::string_view cmd, std::chrono::
     // &&, ||) as popen("/bin/sh -c …") does on Linux. cmd's special-case
     // /C parsing strips the outer quote pair when the inner text contains
     // additional quotes, which is the common case here.
-    std::string wrapped = "cmd /C \"" + std::string(cmd) + "\"";
+    std::string wrapped = std::format("cmd /C \"{}\"", std::string(cmd));
     std::vector<char> cmdBuf(wrapped.begin(), wrapped.end());
     cmdBuf.push_back('\0');
 
-    BOOL ok = CreateProcessA(
+    BOOL ok = CreateProcessA(nullptr, cmdBuf.data(), nullptr, nullptr, TRUE, CREATE_NO_WINDOW | CREATE_SUSPENDED, nullptr, nullptr, &si, &pi);
-        nullptr, cmdBuf.data(), nullptr, nullptr, TRUE,
-        CREATE_NO_WINDOW | CREATE_SUSPENDED,
-        nullptr, nullptr, &si, &pi);
     if (!ok) {
         CloseHandle(readEnd);
         CloseHandle(writeEnd);
@@ -226,9 +250,7 @@ CommandResult Crafter::RunCommandWithTimeout(std::string_view cmd, std::chrono::
         }
     });
 
-    DWORD waitMs = static_cast<DWORD>(std::min<long long>(
+    DWORD waitMs = static_cast<DWORD>(std::min<std::int64_t>(static_cast<std::int64_t>(timeout.count()) * 1000LL, static_cast<std::int64_t>(INFINITE) - 1));
-        static_cast<long long>(timeout.count()) * 1000LL,
-        static_cast<long long>(INFINITE) - 1));
     DWORD waitResult = WaitForSingleObject(pi.hProcess, waitMs);
 
     if (waitResult == WAIT_TIMEOUT) {
@@ -245,9 +267,9 @@ CommandResult Crafter::RunCommandWithTimeout(std::string_view cmd, std::chrono::
         // so the runner shows 💥 instead of a numeric exit code.
         if ((exit & 0xC0000000) == 0xC0000000) {
             result.crashed = true;
-            result.signal = static_cast<int>(exit);
+            result.signal = static_cast<std::int32_t>(exit);
         }
-        result.exitCode = static_cast<int>(exit);
+        result.exitCode = static_cast<std::int32_t>(exit);
     }
 
     reader.join();
@@ -269,7 +291,7 @@ fs::path Crafter::GetCacheDir() {
 }
 
 namespace {
-    constexpr std::array<std::string_view, 10> kCrafterBuildModules = {
+    constexpr std::array<std::string_view, 11> CrafterBuildModules = {
         "Crafter.Build-Shader",
         "Crafter.Build-Platform",
         "Crafter.Build-Interface",
@@ -277,6 +299,7 @@ namespace {
         "Crafter.Build-External",
         "Crafter.Build-Clang",
         "Crafter.Build-Test",
+        "Crafter.Build-Lint",
         "Crafter.Build-Progress",
         "Crafter.Build-Asset",
         "Crafter.Build",
@@ -305,9 +328,9 @@ std::string Crafter::GetBaseCommand(const Configuration& config) {
 namespace {
     void EnsureCrafterBuildPcms(const fs::path& sourceDir, const fs::path& cacheDir) {
         CacheLock lock(cacheDir);
-        for (std::string_view name : kCrafterBuildModules) {
+        for (std::string_view name : CrafterBuildModules) {
-            fs::path cppmPath = sourceDir / (std::string(name) + ".cppm");
+            fs::path cppmPath = sourceDir / std::format("{}.cppm", name);
-            fs::path pcmPath = cacheDir / (std::string(name) + ".pcm");
+            fs::path pcmPath = cacheDir / std::format("{}.pcm", name);
             if (!fs::exists(cppmPath)) {
                 throw std::runtime_error(std::format("module source {} not found in {} (set CRAFTER_BUILD_HOME)", name, sourceDir.string()));
             }
@@ -336,7 +359,7 @@ Configuration Crafter::LoadProject(const fs::path& projectFile, std::span<const
     if (!fs::exists(buildDir)) {
         fs::create_directories(buildDir);
     }
-    fs::path dllPath = buildDir / (absProject.stem().string() + ".dll");
+    fs::path dllPath = buildDir / std::format("{}.dll", absProject.stem().string());
 
     char hostExeBuf[MAX_PATH];
     DWORD hostExeLen = GetModuleFileNameA(nullptr, hostExeBuf, MAX_PATH);
@@ -361,9 +384,7 @@ Configuration Crafter::LoadProject(const fs::path& projectFile, std::span<const
 
     EnsureCrafterBuildPcms(sourceDir, cacheDir);
 
-    bool stale = !fs::exists(dllPath)
+    bool stale = !fs::exists(dllPath) || fs::last_write_time(dllPath) < fs::last_write_time(absProject) || fs::last_write_time(dllPath) < fs::last_write_time(hostExe);
-        || fs::last_write_time(dllPath) < fs::last_write_time(absProject)
-        || fs::last_write_time(dllPath) < fs::last_write_time(hostExe);
 
     if (stale) {
         fs::path crafterBuildLib = hostExe.parent_path() / "crafter-build.lib";
@@ -427,9 +448,7 @@ namespace {
     std::string MingwGccVersion() {
         fs::path includeRoot = MingwPrefix() / "include" / "c++";
         if (!fs::exists(includeRoot)) {
-            throw std::runtime_error(std::format(
+            throw std::runtime_error(std::format("mingw-w64 not found at {} (install msys2 mingw-w64-x86_64-toolchain or set CRAFTER_MINGW_DIR)", MingwPrefix().string()));
-                "mingw-w64 not found at {} (install msys2 mingw-w64-x86_64-toolchain or set CRAFTER_MINGW_DIR)",
-                MingwPrefix().string()));
         }
         std::vector<std::string> versions;
         for (const auto& entry : fs::directory_iterator(includeRoot)) {
@@ -505,13 +524,11 @@ namespace {
     void EnsureCrafterBuildPcms(const fs::path& sourceDir, const fs::path& cacheDir) {
         CacheLock lock(cacheDir);
         fs::path prefix = MingwPrefix();
-        for (std::string_view name : kCrafterBuildModules) {
+        for (std::string_view name : CrafterBuildModules) {
-            fs::path cppmPath = sourceDir / (std::string(name) + ".cppm");
+            fs::path cppmPath = sourceDir / std::format("{}.cppm", name);
-            fs::path pcmPath = cacheDir / (std::string(name) + ".pcm");
+            fs::path pcmPath = cacheDir / std::format("{}.pcm", name);
             if (!fs::exists(cppmPath)) {
-                throw std::runtime_error(std::format(
+                throw std::runtime_error(std::format("module source {} not found in {} (set CRAFTER_BUILD_HOME)", name, sourceDir.string()));
-                    "module source {} not found in {} (set CRAFTER_BUILD_HOME)",
-                    name, sourceDir.string()));
             }
             if (fs::exists(pcmPath) && fs::last_write_time(cppmPath) < fs::last_write_time(pcmPath)) {
                 continue;
@@ -526,8 +543,7 @@ namespace {
                 prefix.string(), cacheDir.string(), cppmPath.string(), pcmPath.string());
             CommandResult r = Crafter::RunCommandChecked(cmd);
             if (r.exitCode != 0) {
-                throw std::runtime_error(std::format(
+                throw std::runtime_error(std::format("Failed to precompile {} (exit {}): {}", name, r.exitCode, r.output));
-                    "Failed to precompile {} (exit {}): {}", name, r.exitCode, r.output));
             }
         }
     }
@@ -537,7 +553,7 @@ Configuration Crafter::LoadProject(const fs::path& projectFile, std::span<const
     fs::path absProject = fs::canonical(projectFile);
     fs::path buildDir = absProject.parent_path() / "build";
     if (!fs::exists(buildDir)) fs::create_directories(buildDir);
-    fs::path dllPath = buildDir / (absProject.stem().string() + ".dll");
+    fs::path dllPath = buildDir / std::format("{}.dll", absProject.stem().string());
 
     char hostExeBuf[MAX_PATH];
     DWORD hostExeLen = GetModuleFileNameA(nullptr, hostExeBuf, MAX_PATH);
@@ -562,9 +578,7 @@ Configuration Crafter::LoadProject(const fs::path& projectFile, std::span<const
 
     EnsureCrafterBuildPcms(sourceDir, cacheDir);
 
-    bool stale = !fs::exists(dllPath)
+    bool stale = !fs::exists(dllPath) || fs::last_write_time(dllPath) < fs::last_write_time(absProject) || fs::last_write_time(dllPath) < fs::last_write_time(hostExe);
-        || fs::last_write_time(dllPath) < fs::last_write_time(absProject)
-        || fs::last_write_time(dllPath) < fs::last_write_time(hostExe);
 
     if (stale) {
         // The import lib lives next to the launcher exe (Build()'s mingw
@@ -589,8 +603,7 @@ Configuration Crafter::LoadProject(const fs::path& projectFile, std::span<const
 
         std::string result = RunCommand(compileCmd);
         if (!result.empty()) {
-            throw std::runtime_error(std::format(
+            throw std::runtime_error(std::format("Failed to compile project {}: {}", absProject.string(), result));
-                "Failed to compile project {}: {}", absProject.string(), result));
         }
     }
 
@@ -604,15 +617,13 @@ Configuration Crafter::LoadProject(const fs::path& projectFile, std::span<const
 
     HMODULE handle = LoadLibraryA(dllPath.string().c_str());
     if (!handle) {
-        throw std::runtime_error(std::format(
+        throw std::runtime_error(std::format("Failed to load project {}: error {}", dllPath.string(), GetLastError()));
-            "Failed to load project {}: error {}", dllPath.string(), GetLastError()));
     }
 
     using ProjectFn = Configuration (*)(std::span<const std::string_view>);
     auto fn = reinterpret_cast<ProjectFn>(GetProcAddress(handle, "CrafterBuildProject"));
     if (!fn) {
-        throw std::runtime_error(std::format(
+        throw std::runtime_error(std::format("CrafterBuildProject not found in {}: error {}", dllPath.string(), GetLastError()));
-            "CrafterBuildProject not found in {}: error {}", dllPath.string(), GetLastError()));
     }
 
     return fn(args);
@@ -626,7 +637,7 @@ std::string Crafter::RunCommand(const std::string_view cmd) {
     std::array<char, 128> buffer;
     std::string result;
 
-    std::string with = std::string(cmd) + " 2>&1";
+    std::string with = std::format("{} 2>&1", cmd);
     // Open pipe to file
     FILE* pipe = popen(with.c_str(), "r");
     if (!pipe) throw std::runtime_error("popen() failed!");
@@ -645,7 +656,7 @@ CommandResult Crafter::RunCommandChecked(std::string_view cmd) {
     std::array<char, 128> buffer;
     CommandResult result{};
 
-    std::string with = std::string(cmd) + " 2>&1";
+    std::string with = std::format("{} 2>&1", cmd);
     FILE* pipe = popen(with.c_str(), "r");
     if (!pipe) throw std::runtime_error("popen() failed!");
 
@@ -653,7 +664,7 @@ CommandResult Crafter::RunCommandChecked(std::string_view cmd) {
         result.output += buffer.data();
     }
 
-    int status = pclose(pipe);
+    std::int32_t status = pclose(pipe);
     if (WIFEXITED(status)) {
         result.exitCode = WEXITSTATUS(status);
     } else if (WIFSIGNALED(status)) {
@@ -670,9 +681,7 @@ CommandResult Crafter::RunCommandWithTimeout(std::string_view cmd, std::chrono::
     std::array<char, 128> buffer;
     CommandResult result{};
 
-    std::string wrapped = std::format(
+    std::string wrapped = std::format("timeout --kill-after=2 {} {} 2>&1", timeout.count(), cmd);
-        "timeout --kill-after=2 {} {} 2>&1",
-        timeout.count(), cmd);
 
     FILE* pipe = popen(wrapped.c_str(), "r");
     if (!pipe) throw std::runtime_error("popen() failed!");
@@ -681,9 +690,9 @@ CommandResult Crafter::RunCommandWithTimeout(std::string_view cmd, std::chrono::
         result.output += buffer.data();
     }
 
-    int status = pclose(pipe);
+    std::int32_t status = pclose(pipe);
     if (WIFEXITED(status)) {
-        int code = WEXITSTATUS(status);
+        std::int32_t code = WEXITSTATUS(status);
         if (code == 124) {
             result.timedOut = true;
             result.exitCode = 124;
@@ -774,7 +783,7 @@ std::string Crafter::BuildStdPcm(const Configuration& config, fs::path stdPcm) {
         // (e.g. -mrelaxed-simd) so the std BMI is feature-compatible. wasm only;
         // wasmVariantFlags is empty on every other path.
         if (isWasm) {
-            for (const std::string& f : config.wasmVariantFlags) archFlags += " " + f;
+            for (const std::string& f : config.wasmVariantFlags) archFlags += std::format(" {}", f);
         }
         // non-wasm cross builds: the driver ranks the host toolchain's own
         // libc++ headers (<install>/../include/c++/v1) above --sysroot, so
@@ -814,7 +823,7 @@ std::string Crafter::GetBaseCommand(const Configuration& config) {
 }
 
 namespace {
-    constexpr std::array<std::string_view, 10> kCrafterBuildModules = {
+    constexpr std::array<std::string_view, 11> CrafterBuildModules = {
         "Crafter.Build-Shader",
         "Crafter.Build-Platform",
         "Crafter.Build-Interface",
@@ -822,6 +831,7 @@ namespace {
         "Crafter.Build-External",
         "Crafter.Build-Clang",
         "Crafter.Build-Test",
+        "Crafter.Build-Lint",
         "Crafter.Build-Progress",
         "Crafter.Build-Asset",
         "Crafter.Build",
@@ -829,9 +839,9 @@ namespace {
 
     void EnsureCrafterBuildPcms(const fs::path& sourceDir, const fs::path& cacheDir) {
         CacheLock lock(cacheDir);
-        for (std::string_view name : kCrafterBuildModules) {
+        for (std::string_view name : CrafterBuildModules) {
-            fs::path cppmPath = sourceDir / (std::string(name) + ".cppm");
+            fs::path cppmPath = sourceDir / std::format("{}.cppm", name);
-            fs::path pcmPath = cacheDir / (std::string(name) + ".pcm");
+            fs::path pcmPath = cacheDir / std::format("{}.pcm", name);
             if (!fs::exists(cppmPath)) {
                 throw std::runtime_error(std::format("module source {} not found in {} (set CRAFTER_BUILD_HOME)", name, sourceDir.string()));
             }
@@ -859,7 +869,7 @@ Configuration Crafter::LoadProject(const fs::path& projectFile, std::span<const
     if (!fs::exists(buildDir)) {
         fs::create_directories(buildDir);
     }
-    fs::path soPath = buildDir / (absProject.stem().string() + ".so");
+    fs::path soPath = buildDir / std::format("{}.so", absProject.stem().string());
 
     fs::path hostExe = fs::read_symlink("/proc/self/exe");
 
@@ -879,9 +889,7 @@ Configuration Crafter::LoadProject(const fs::path& projectFile, std::span<const
 
     EnsureCrafterBuildPcms(sourceDir, cacheDir);
 
-    bool stale = !fs::exists(soPath)
+    bool stale = !fs::exists(soPath) || fs::last_write_time(soPath) < fs::last_write_time(absProject) || fs::last_write_time(soPath) < fs::last_write_time(hostExe);
-        || fs::last_write_time(soPath) < fs::last_write_time(absProject)
-        || fs::last_write_time(soPath) < fs::last_write_time(hostExe);
 
     if (stale) {
         std::string compileCmd = std::format(

implementations/Crafter.Build-Progress.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include <stdio.h>
@@ -22,21 +22,21 @@ import std;
 import :Progress;
 
 namespace {
-    std::mutex g_mutex;
+    std::mutex StateMutex;
-    std::atomic<int> g_total{0};
+    std::atomic<std::int32_t> Total{0};
-    std::atomic<int> g_done{0};
+    std::atomic<std::int32_t> Done{0};
-    Crafter::Progress::Verbosity g_verbosity = Crafter::Progress::Verbosity::Default;
+    Crafter::Progress::Verbosity ActiveVerbosity = Crafter::Progress::Verbosity::Default;
-    bool g_isTty = false;
+    bool IsTty = false;
-    bool g_lineDirty = false;        // status line has uncleared content
+    bool LineDirty = false;        // status line has uncleared content
-    bool g_finalized = false;
+    bool Finalized = false;
-    std::chrono::steady_clock::time_point g_startTime = std::chrono::steady_clock::now();
+    std::chrono::steady_clock::time_point StartTime = std::chrono::steady_clock::now();
 
-    int TerminalWidth() {
+    std::int32_t TerminalWidth() {
     #if defined(_WIN32)
         HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
         CONSOLE_SCREEN_BUFFER_INFO info;
         if (h != INVALID_HANDLE_VALUE && GetConsoleScreenBufferInfo(h, &info)) {
-            int w = info.srWindow.Right - info.srWindow.Left + 1;
+            std::int32_t w = info.srWindow.Right - info.srWindow.Left + 1;
             if (w > 0) return w;
         }
     #else
@@ -46,21 +46,21 @@ namespace {
         }
     #endif
         if (const char* col = std::getenv("COLUMNS")) {
-            try { int c = std::stoi(col); if (c > 0) return c; } catch (...) {}
+            try { std::int32_t c = std::stoi(col); if (c > 0) return c; } catch (...) {}
         }
         return 80;
     }
 
-    // Caller holds g_mutex.
+    // Caller holds StateMutex.
     void RenderStatus(std::string_view label) {
-        if (g_verbosity != Crafter::Progress::Verbosity::Default || !g_isTty) return;
+        if (ActiveVerbosity != Crafter::Progress::Verbosity::Default || !IsTty) return;
-        int done = g_done.load(std::memory_order_relaxed);
+        std::int32_t done = Done.load(std::memory_order_relaxed);
-        int total = g_total.load(std::memory_order_relaxed);
+        std::int32_t total = Total.load(std::memory_order_relaxed);
         std::string prefix = std::format("[{}/{}] ", done, total);
-        int width = TerminalWidth();
+        std::int32_t width = TerminalWidth();
-        int avail = width - static_cast<int>(prefix.size()) - 1;
+        std::int32_t avail = width - static_cast<std::int32_t>(prefix.size()) - 1;
         std::string trimmed{label};
-        if (avail > 0 && static_cast<int>(trimmed.size()) > avail) {
+        if (avail > 0 && static_cast<std::int32_t>(trimmed.size()) > avail) {
             trimmed.resize(static_cast<std::size_t>(avail));
         }
         // \r returns to col 0, \033[2K erases the whole line. No newline.
@@ -68,15 +68,15 @@ namespace {
         std::fputs(prefix.c_str(), stdout);
         std::fputs(trimmed.c_str(), stdout);
         std::fflush(stdout);
-        g_lineDirty = true;
+        LineDirty = true;
     }
 
-    // Caller holds g_mutex.
+    // Caller holds StateMutex.
     void ClearLineLocked() {
-        if (g_lineDirty) {
+        if (LineDirty) {
             std::fputs("\r\033[2K", stdout);
             std::fflush(stdout);
-            g_lineDirty = false;
+            LineDirty = false;
         }
     }
 }
@@ -84,66 +84,64 @@ namespace {
 namespace Crafter::Progress {
 
 void SetVerbosity(Verbosity v) {
-    std::lock_guard lock(g_mutex);
+    std::lock_guard lock(StateMutex);
-    g_verbosity = v;
+    ActiveVerbosity = v;
-    g_isTty = CRAFTER_PROGRESS_ISATTY(STDOUT_FILENO) != 0;
+    IsTty = CRAFTER_PROGRESS_ISATTY(STDOUT_FILENO) != 0;
-    g_startTime = std::chrono::steady_clock::now();
+    StartTime = std::chrono::steady_clock::now();
-    g_total.store(0);
+    Total.store(0);
-    g_done.store(0);
+    Done.store(0);
-    g_finalized = false;
+    Finalized = false;
 }
 
 Verbosity GetVerbosity() {
-    std::lock_guard lock(g_mutex);
+    std::lock_guard lock(StateMutex);
-    return g_verbosity;
+    return ActiveVerbosity;
 }
 
 Task::Task(std::string label) : label_(std::move(label)) {
-    g_total.fetch_add(1, std::memory_order_relaxed);
+    Total.fetch_add(1, std::memory_order_relaxed);
-    std::lock_guard lock(g_mutex);
+    std::lock_guard lock(StateMutex);
-    if (g_verbosity == Verbosity::Default && g_isTty) {
+    if (ActiveVerbosity == Verbosity::Default && IsTty) {
         RenderStatus(label_);
     }
 }
 
 Task::~Task() {
-    int done = g_done.fetch_add(1, std::memory_order_relaxed) + 1;
+    std::int32_t done = Done.fetch_add(1, std::memory_order_relaxed) + 1;
-    std::lock_guard lock(g_mutex);
+    std::lock_guard lock(StateMutex);
-    if (g_verbosity == Verbosity::Default) {
+    if (ActiveVerbosity == Verbosity::Default) {
-        if (g_isTty) {
+        if (IsTty) {
             RenderStatus(label_);
         } else {
             // Non-TTY: one append-only line per completed task (ninja-style).
-            int total = g_total.load(std::memory_order_relaxed);
+            std::int32_t total = Total.load(std::memory_order_relaxed);
             std::println("[{}/{}] {}", done, total, label_);
         }
     }
 }
 
 void EchoCommand(std::string_view command) {
-    std::lock_guard lock(g_mutex);
+    std::lock_guard lock(StateMutex);
-    if (g_verbosity == Verbosity::Verbose) {
+    if (ActiveVerbosity == Verbosity::Verbose) {
         std::println("$ {}", command);
     }
 }
 
 void Clear() {
-    std::lock_guard lock(g_mutex);
+    std::lock_guard lock(StateMutex);
     ClearLineLocked();
 }
 
 void Finalize() {
-    std::lock_guard lock(g_mutex);
+    std::lock_guard lock(StateMutex);
-    if (g_finalized) return;
+    if (Finalized) return;
-    g_finalized = true;
+    Finalized = true;
     ClearLineLocked();
-    if (g_verbosity == Verbosity::Quiet) return;
+    if (ActiveVerbosity == Verbosity::Quiet) return;
-    int done = g_done.load();
+    std::int32_t done = Done.load();
     if (done == 0) return;  // Nothing happened (cached build); stay silent.
-    auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
+    auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::steady_clock::now() - StartTime);
-        std::chrono::steady_clock::now() - g_startTime);
+    std::println("Built {} step{} in {}ms", done, done == 1 ? "" : "s", elapsed.count());
-    std::println("Built {} step{} in {}ms",
-        done, done == 1 ? "" : "s", elapsed.count());
 }
 
 } // namespace Crafter::Progress

implementations/Crafter.Build-Shader.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "SPIRV/GlslangToSpv.h"
@@ -72,11 +72,11 @@ namespace Crafter {
 
         std::string pathStr = path.string();
         const char* file_name_list[1] = { pathStr.c_str() };
-        const char* shader_source = src.data();
+        const char* shaderSource = src.data();
-        const int shader_source_len = static_cast<int>(src.size());
+        const std::int32_t shaderSourceLen = static_cast<std::int32_t>(src.size());
 
         glslang::TShader shader(glslangType);
-        shader.setStringsWithLengthsAndNames(&shader_source, &shader_source_len, file_name_list, 1);
+        shader.setStringsWithLengthsAndNames(&shaderSource, &shaderSourceLen, file_name_list, 1);
         shader.setEntryPoint(entrypoint.c_str());
         shader.setSourceEntryPoint(entrypoint.c_str());
         shader.setEnvTarget(glslang::EShTargetSpv, glslang::EShTargetSpv_1_4);

implementations/Crafter.Build-Test.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 export module Crafter.Build:Test_impl;
@@ -13,41 +13,15 @@ using namespace Crafter;
 
 namespace {
     bool TargetIsWindows(std::string_view target) {
-        return target.find("windows") != std::string_view::npos
+        return target.find("windows") != std::string_view::npos || target.find("mingw") != std::string_view::npos;
-            || target.find("mingw") != std::string_view::npos;
     }
 
     fs::path TestBinaryPath(const Configuration& cfg) {
         fs::path outputDir = cfg.BinDir();
-        return outputDir / (TargetIsWindows(cfg.target) ? cfg.outputName + ".exe" : cfg.outputName);
+        return outputDir / (TargetIsWindows(cfg.target) ? std::format("{}.exe", cfg.outputName) : cfg.outputName);
     }
 
-    bool MatchGlob(std::string_view glob, std::string_view name) {
+    // MatchGlob/MatchAny live in :Platform — shared with the lint verb.
-        std::size_t gi = 0, ni = 0, star = std::string_view::npos, mark = 0;
-        while (ni < name.size()) {
-            if (gi < glob.size() && (glob[gi] == '?' || glob[gi] == name[ni])) {
-                ++gi; ++ni;
-            } else if (gi < glob.size() && glob[gi] == '*') {
-                star = gi++;
-                mark = ni;
-            } else if (star != std::string_view::npos) {
-                gi = star + 1;
-                ni = ++mark;
-            } else {
-                return false;
-            }
-        }
-        while (gi < glob.size() && glob[gi] == '*') ++gi;
-        return gi == glob.size();
-    }
-
-    bool MatchAny(std::span<const std::string> globs, std::string_view name) {
-        if (globs.empty()) return true;
-        for (const auto& g : globs) {
-            if (MatchGlob(g, name)) return true;
-        }
-        return false;
-    }
 
     std::string ShellQuoteSh(std::string_view s) {
         std::string out;
@@ -118,7 +92,7 @@ namespace {
         return out;
     }
 
-    std::string SignalName(int sig) {
+    std::string SignalName(std::int32_t sig) {
         switch (sig) {
             case 1: return "SIGHUP";
             case 2: return "SIGINT";
@@ -139,7 +113,7 @@ namespace {
         std::error_code ec;
         fs::create_directories(logDir, ec);
         if (ec) return;
-        std::ofstream(logDir / (name + ".log")) << output;
+        std::ofstream(logDir / (std::format("{}.log", name))) << output;
     }
 
     void PrintResult(const TestResult& r, std::string_view runnerName) {
@@ -174,19 +148,16 @@ namespace {
                 std::println("⏱  {}{} ({}ms) timeout", r.name, runnerSuffix, ms);
                 break;
             case TestOutcome::Skipped:
-                std::println("⏭  {}{} skipped: {}", r.name, runnerSuffix,
+                std::println("⏭  {}{} skipped: {}", r.name, runnerSuffix, r.output.empty() ? std::string("(no reason)") : r.output);
-                    r.output.empty() ? std::string("(no reason)") : r.output);
                 break;
         }
     }
 }
 
 namespace {
-    std::atomic<Configuration*> g_parentProject{nullptr};
+    std::atomic<Configuration*> ParentProject{nullptr};
 
-    Configuration* FindLibInTree(Configuration* root,
+    Configuration* FindLibInTree(Configuration* root, std::string_view name, std::unordered_set<Configuration*>& seen) {
-                                  std::string_view name,
-                                  std::unordered_set<Configuration*>& seen) {
         if (!seen.insert(root).second) return nullptr;
         if (root->name == name) return root;
         for (Configuration* dep : root->dependencies) {
@@ -197,20 +168,17 @@ namespace {
 }
 
 void Crafter::SetParentProject(Configuration* parent) {
-    g_parentProject.store(parent);
+    ParentProject.store(parent);
 }
 
 Configuration* Crafter::ParentLib(std::string_view name) {
-    Configuration* root = g_parentProject.load();
+    Configuration* root = ParentProject.load();
     if (!root) {
-        throw std::runtime_error(std::format(
+        throw std::runtime_error(std::format("Crafter::ParentLib('{}'): no parent project set", name));
-            "Crafter::ParentLib('{}'): no parent project set", name));
     }
     std::unordered_set<Configuration*> seen;
     if (auto found = FindLibInTree(root, name, seen)) return found;
-    throw std::runtime_error(std::format(
+    throw std::runtime_error(std::format("Crafter::ParentLib('{}'): not found in parent project '{}'", name, root->name));
-        "Crafter::ParentLib('{}'): not found in parent project '{}'",
-        name, root->name));
 }
 
 TestRunner TestRunner::Local() {
@@ -286,9 +254,7 @@ TestRunner TestRunner::ForTarget(const Configuration& cfg) {
             // emulated loader then searches ITS default paths against the
             // host filesystem, picking up host-arch libraries from /lib —
             // LD_LIBRARY_PATH steers it back into the sysroot.
-            r.exec = std::format(
+            r.exec = std::format("env QEMU_LD_PREFIX={0} LD_LIBRARY_PATH={0}/lib:{0}/usr/lib {1}", cfg.sysroot, r.exec);
-                "env QEMU_LD_PREFIX={0} LD_LIBRARY_PATH={0}/lib:{0}/usr/lib {1}",
-                cfg.sysroot, r.exec);
         }
         return r;
     }
@@ -317,9 +283,7 @@ namespace {
         if (spec.starts_with("cmd:") && spec.size() > 4) {
             return TestRunner::Cmd(std::string(spec.substr(4)));
         }
-        throw std::runtime_error(std::format(
+        throw std::runtime_error(std::format("TestRunner::FromSpec: unrecognized runner spec '{}' " "(expected 'local' or 'cmd:<binary>')", spec));
-            "TestRunner::FromSpec: unrecognized runner spec '{}' "
-            "(expected 'local' or 'cmd:<binary>')", spec));
     }
 }
 
@@ -411,8 +375,7 @@ namespace {
                     return {false, std::format("env '{}' unset", arg)};
                 }
             } else {
-                return {false, std::format(
+                return {false, std::format("unknown require kind '{}' (expected tool/file/env)", kind)};
-                    "unknown require kind '{}' (expected tool/file/env)", kind)};
             }
         }
         return {true, ""};
@@ -479,9 +442,7 @@ TestBuilder Configuration::AddTest(std::string_view name, std::span<fs::path> in
     return TestBuilder{this, tests.size() - 1};
 }
 
-void Configuration::AddMarchVariants(std::string_view name,
+void Configuration::AddMarchVariants(std::string_view name, std::span<fs::path> interfaces, std::span<const MarchTier> tiers) {
-                                     std::span<fs::path> interfaces,
-                                     std::span<const MarchTier> tiers) {
     for (const auto& tier : tiers) {
         Test t;
         t.config.path = "./";
@@ -507,25 +468,25 @@ void Configuration::AddMarchVariants(std::string_view name,
     }
 }
 
-TestBuilder& TestBuilder::Path(fs::path p)                  { test().config.path = std::move(p); return *this; }
+TestBuilder& TestBuilder::Path(fs::path p)                  { Ref().config.path = std::move(p); return *this; }
-TestBuilder& TestBuilder::Target(std::string t)             { test().config.target = std::move(t); return *this; }
+TestBuilder& TestBuilder::Target(std::string t)             { Ref().config.target = std::move(t); return *this; }
-TestBuilder& TestBuilder::March(std::string m)              { test().config.march = std::move(m); return *this; }
+TestBuilder& TestBuilder::March(std::string m)              { Ref().config.march = std::move(m); return *this; }
-TestBuilder& TestBuilder::Mtune(std::string m)              { test().config.mtune = std::move(m); return *this; }
+TestBuilder& TestBuilder::Mtune(std::string m)              { Ref().config.mtune = std::move(m); return *this; }
-TestBuilder& TestBuilder::Sysroot(fs::path s)               { test().config.sysroot = s.string(); return *this; }
+TestBuilder& TestBuilder::Sysroot(fs::path s)               { Ref().config.sysroot = s.string(); return *this; }
-TestBuilder& TestBuilder::Debug(bool d)                     { test().config.debug = d; return *this; }
+TestBuilder& TestBuilder::Debug(bool d)                     { Ref().config.debug = d; return *this; }
 TestBuilder& TestBuilder::Define(std::string n, std::string v) {
-    test().config.defines.push_back({std::move(n), std::move(v)});
+    Ref().config.defines.push_back({std::move(n), std::move(v)});
     return *this;
 }
-TestBuilder& TestBuilder::Timeout(std::chrono::seconds s)   { test().timeout = s; return *this; }
+TestBuilder& TestBuilder::Timeout(std::chrono::seconds s)   { Ref().timeout = s; return *this; }
-TestBuilder& TestBuilder::Args(std::vector<std::string> a)  { test().args = std::move(a); return *this; }
+TestBuilder& TestBuilder::Args(std::vector<std::string> a)  { Ref().args = std::move(a); return *this; }
-TestBuilder& TestBuilder::Requires(std::string r)           { test().requires_.push_back(std::move(r)); return *this; }
+TestBuilder& TestBuilder::Requires(std::string r)           { Ref().requires_.push_back(std::move(r)); return *this; }
 TestBuilder& TestBuilder::Dependencies(std::vector<Configuration*> d) {
-    test().config.dependencies = std::move(d);
+    Ref().config.dependencies = std::move(d);
     return *this;
 }
-TestBuilder& TestBuilder::LinkFlag(std::string f)           { test().config.linkFlags.push_back(std::move(f)); return *this; }
+TestBuilder& TestBuilder::LinkFlag(std::string f)           { Ref().config.linkFlags.push_back(std::move(f)); return *this; }
-TestBuilder& TestBuilder::CompileFlag(std::string f)        { test().config.compileFlags.push_back(std::move(f)); return *this; }
+TestBuilder& TestBuilder::CompileFlag(std::string f)        { Ref().config.compileFlags.push_back(std::move(f)); return *this; }
 
 TestSummary Crafter::RunTests(Configuration& projectCfg, const RunTestsOptions& opts, std::span<const std::string_view> projectArgs) {
     // Multi-target sweep: when no --target= was given, the run covers every
@@ -590,10 +551,10 @@ TestSummary Crafter::RunTests(Configuration& projectCfg, const RunTestsOptions&
         return summary;
     }
 
-    int jobs = opts.jobs > 0
+    std::int32_t jobs = opts.jobs > 0
         ? opts.jobs
         : std::max(1u, std::thread::hardware_concurrency());
-    jobs = std::min(jobs, static_cast<int>(filtered.size()));
+    jobs = std::min(jobs, static_cast<std::int32_t>(filtered.size()));
 
     std::unordered_map<fs::path, std::shared_future<BuildResult>> depResults;
     std::mutex depMutex;
@@ -651,10 +612,7 @@ TestSummary Crafter::RunTests(Configuration& projectCfg, const RunTestsOptions&
                 if (!tool.empty() && !RequiresMentionsTool(t.requires_, tool)) {
                     r.outcome = TestOutcome::Fail;
                     r.exitCode = -1;
-                    r.output = std::format(
+                    r.output = std::format("runner '{}' unavailable and not declared in requires " "(add .Requires(\"tool:{}\") to permit skipping)", t.runner.name, tool);
-                        "runner '{}' unavailable and not declared in requires "
-                        "(add .Requires(\"tool:{}\") to permit skipping)",
-                        t.runner.name, tool);
                 } else {
                     r.outcome = TestOutcome::Skipped;
                     r.output = std::format("runner '{}' not available", t.runner.name);
@@ -718,7 +676,7 @@ TestSummary Crafter::RunTests(Configuration& projectCfg, const RunTestsOptions&
 
     std::vector<std::jthread> threads;
     threads.reserve(jobs);
-    for (int j = 0; j < jobs; ++j) {
+    for (std::int32_t j = 0; j < jobs; ++j) {
         threads.emplace_back(worker);
     }
     threads.clear(); // joins all jthreads

implementations/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 #include <cstdio>
 #if defined(_WIN32)

interfaces/Crafter.Build-Api.h

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 #pragma once
 

interfaces/Crafter.Build-Asset.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"

interfaces/Crafter.Build-Clang.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"
@@ -96,12 +96,91 @@ export namespace Crafter {
     struct TestResult {
         std::string name;
         TestOutcome outcome = TestOutcome::Pass;
-        int exitCode = 0;
+        std::int32_t exitCode = 0;
-        int signal = 0;
+        std::int32_t signal = 0;
         std::chrono::milliseconds duration{0};
         std::string output;
     };
 
+    // One lint diagnostic. Produced by LintContext::Report — or derived by
+    // the driver when a transform rule's SetContent output differs from the
+    // file on disk ("would reformat") — collected and printed compiler-style
+    // by RunLint (Crafter.Build:Lint):
+    //   <file>:<line>: warning: <message> [<rule>]
+    struct LintFinding {
+        fs::path file;
+        std::size_t line = 0;   // 1-based; 0 = whole-file finding
+        std::string rule;       // name of the rule that produced it
+        std::string message;
+    };
+
+    // Parsed `// lint-disable-*` suppression directives for one file (see
+    // LintContext::Suppressed). Line keys are 1-based and refer to the line a
+    // next-line directive TARGETS (the line after the comment).
+    struct LintSuppressions {
+        bool fileAll = false;
+        std::unordered_set<std::string> fileRules;
+        std::unordered_set<std::size_t> lineAll;
+        std::unordered_map<std::size_t, std::unordered_set<std::string>> lineRules;
+    };
+
+    // Per-file view handed to each LintRule's check callback. Every member
+    // function is out-of-line and CRAFTER_API (defined in Crafter.Build:Lint's
+    // implementation unit) because rule lambdas execute from the user's
+    // project DLL on Windows — clang does not emit module-attached in-class
+    // inline bodies into consumers (see ArgQuery below).
+    struct LintContext {
+        fs::path file;                        // absolute path of the file under lint
+        std::string content;                  // whole file as read from disk
+        std::vector<std::string_view> lines;  // views into `content`, one per line, no '\n'
+
+        CRAFTER_API std::string Extension() const;              // ".cppm", ".cpp", ".h", ...
+        CRAFTER_API std::string_view Line(std::size_t n) const; // 1-based; empty if out of range
+        // `content` with //-comments, /*...*/ comments and string/char literal
+        // bodies blanked to spaces, newlines preserved — offsets and line
+        // numbers stay valid. Built on first call, cached per file. Raw string
+        // literals are not recognized (v1 limitation).
+        CRAFTER_API const std::string& CommentStripped();
+        // Record a finding at `line` (1-based; pass 0 for a whole-file finding).
+        CRAFTER_API void Report(std::size_t line, std::string message);
+        // Replace the file's content. Makes this rule a *transform*:
+        // `crafter-build format` writes the result back to disk; `lint`
+        // derives would-reformat findings from it (dry — never writes).
+        // `lines` is re-split and CommentStripped() re-derives on next call;
+        // string_views taken before this call are invalidated. Recommended
+        // pattern: build the new string, call SetContent once at the end. Do
+        // not assign `content` directly — that bypasses the re-split. May be
+        // combined with Report() in the same rule.
+        CRAFTER_API void SetContent(std::string newContent);
+        // True when `rule` is suppressed at `line` (1-based; 0 = whole-file,
+        // which only file-level directives cover) by a suppression comment:
+        //   // lint-disable-next-line [rules...]   applies to the following line
+        //   // lint-disable-file [rules...]        applies to the whole file
+        // Rule names are space- or comma-separated; none = all rules. The
+        // driver already filters Report()
+        // findings and reverts line-preserving transform edits on suppressed
+        // lines; a transform that MERGES or SPLITS lines must consult this
+        // itself for every line its edit touches (the driver cannot map lines
+        // across a count-changing rewrite). Parsed lazily from the raw lines;
+        // re-parsed after SetContent.
+        CRAFTER_API bool Suppressed(std::string_view rule, std::size_t line);
+
+        // Driver wiring — set by RunLint before each check call. Not for rules.
+        std::string activeRule;
+        std::vector<LintFinding>* sink = nullptr;
+        std::optional<std::string> commentStrippedCache;
+        std::optional<LintSuppressions> suppressionsCache;
+    };
+
+    // A named lint rule: `check` runs once per (rule, file) over the project's
+    // own sources. Rules self-filter by ctx.Extension() / ctx.file. A rule
+    // that calls ctx.SetContent is a transform — defined once, it both gates
+    // `crafter-build lint` and fixes under `crafter-build format`.
+    struct LintRule {
+        std::string name;
+        std::function<void(LintContext&)> check;
+    };
+
     // The host target triple, detected once per process by running
     // `clang++ -print-target-triple` and cached. Used as the default for
     // Configuration::target so projects don't have to hardcode it for the
@@ -172,6 +251,8 @@ export namespace Crafter {
         // wasmVariants instead.
         std::vector<std::string> wasmVariantFlags;
         std::vector<Test> tests;
+        // Lint rules for `crafter-build lint`. Populate via AddLintRule.
+        std::vector<LintRule> lintRules;
         CRAFTER_API void GetInterfacesAndImplementations(std::span<fs::path> interfaces, std::span<fs::path> implementations);
         // Declare a test. Sources default to `tests/<name>/main.cpp` resolved
         // against this Configuration's path; target/march/mtune/sysroot/debug
@@ -188,9 +269,14 @@ export namespace Crafter {
         // `tests/<name>/main.cpp` source and the same interface set, each
         // compiled with the tier's `-march`/`-mtune`. Test names are
         // `<name>-<march>`.
-        CRAFTER_API void AddMarchVariants(std::string_view name,
+        CRAFTER_API void AddMarchVariants(std::string_view name, std::span<fs::path> interfaces, std::span<const struct MarchTier> tiers);
-                                          std::span<fs::path> interfaces,
+        // Register a lint rule for `crafter-build lint` / `format`. Rules
-                                          std::span<const struct MarchTier> tiers);
+        // registered on any Configuration whose path lies inside the project
+        // root are collected (deduplicated by name, root-first) — attach them
+        // to the lib or the exe config, either works. Rules that call
+        // ctx.SetContent are transforms (see LintContext::SetContent).
+        // Defined in Crafter.Build:Lint.
+        CRAFTER_API void AddLintRule(std::string name, std::function<void(LintContext&)> check);
         // Suffix that uniquely identifies this Configuration's compile state.
         // target+march+mtune are spelled out for readability; the rest
         // (type, debug, sysroot, defines, compileFlags) collapse into a short
@@ -198,7 +284,7 @@ export namespace Crafter {
         // compile state can't clobber each other's outputs.
         std::string VariantId() const {
             std::string compileKey;
-            compileKey += std::to_string(static_cast<int>(type));
+            compileKey += std::to_string(static_cast<std::int32_t>(type));
             compileKey += '|';
             compileKey += debug ? '1' : '0';
             compileKey += '|';

interfaces/Crafter.Build-External.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"
@@ -44,10 +44,7 @@ export namespace Crafter {
         fs::file_time_type latestArtifact = fs::file_time_type::min();
     };
 
-    CRAFTER_API ExternalBuildResult BuildExternal(
+    CRAFTER_API ExternalBuildResult BuildExternal(const ExternalDependency& dep, std::string_view target, std::atomic<bool>& cancelled);
-        const ExternalDependency& dep,
-        std::string_view target,
-        std::atomic<bool>& cancelled);
 
     // Specification for a sibling crafter-build project to fetch and depend on.
     // GitSource picks the revision: leave branch + commit empty for the

interfaces/Crafter.Build-Implementation.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"

interfaces/Crafter.Build-Interface.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"

interfaces/Crafter.Build-Lint.cppm

@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+
+module;
+#include "Crafter.Build-Api.h"
+export module Crafter.Build:Lint;
+import std;
+import :Clang;
+
+export namespace Crafter {
+    enum class LintMode {
+        // `lint`: diagnose only; transform output becomes would-reformat
+        // findings. Never writes. The default.
+        Report,
+        // `format --check`: dry run; record the files that would change.
+        Check,
+        // `format`: rewrite changed files in place.
+        Apply,
+    };
+
+    struct RunLintOptions {
+        // Rule-name globs ('*', '?'); empty = every registered rule.
+        std::vector<std::string> globs;
+        // Enumerate matching rule names without running them.
+        bool listOnly = false;
+        LintMode mode = LintMode::Report;
+        // Absolute path of the loaded project.cpp. It is linted too, and its
+        // parent directory is the project root that decides which dependency
+        // Configurations contribute rules/files (GitProject / cache-dir deps
+        // are foreign code and skipped). Empty => fall back to cfg.path.
+        std::filesystem::path projectFile;
+    };
+
+    struct LintSummary {
+        std::vector<LintFinding> findings;  // sorted by (file, line); filled in every mode
+        // Apply: files rewritten on disk. Report/Check: files a transform
+        // would change. The `format` verb's exit code keys off this in Check
+        // mode; formatting files in Apply mode is success.
+        std::vector<std::filesystem::path> changedFiles;
+        std::size_t filesLinted = 0;
+        std::size_t rulesRun = 0;           // rules remaining after glob filter
+        std::size_t errors = 0;             // rule exceptions + write failures
+        bool noRulesDefined = false;        // project registered no rules at all
+        // Host-side only (like TestSummary::AllPassed), safe as in-class inline.
+        bool Clean() const { return findings.empty() && !noRulesDefined; }
+    };
+
+    // Run the project's lint rules over its own sources: module interfaces
+    // (+ partitions), implementations, cFiles, cuda, shaders, declared tests'
+    // sources, and project.cpp itself — for the root Configuration plus every
+    // transitive dependency whose path lies inside the project root. Rules
+    // run in registration order per file, each seeing the previous rule's
+    // transform output; a rule that throws is reverted and surfaced as a
+    // finding + error. Only Apply mode writes to disk, and only files whose
+    // final content differs from the original. Prints per-mode output:
+    // findings compiler-style (Report), would-change paths (Check), or
+    // formatted paths (Apply), plus a summary line.
+    CRAFTER_API LintSummary RunLint(Configuration& projectCfg, const RunLintOptions& opts);
+}

interfaces/Crafter.Build-Platform.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"
@@ -10,11 +10,11 @@ namespace fs = std::filesystem;
 namespace Crafter {
     struct Configuration;
     struct CommandResult {
-        int exitCode = 0;
+        std::int32_t exitCode = 0;
         std::string output;
         bool crashed = false;
         bool timedOut = false;
-        int signal = 0;
+        std::int32_t signal = 0;
     };
     std::string BuildStdPcm(const Configuration& config, fs::path stdPcm);
     fs::path GetCacheDir();
@@ -27,4 +27,8 @@ namespace Crafter {
     // module sources, wasi-runtime/, etc). Honors CRAFTER_BUILD_HOME; otherwise
     // derives <prefix>/share/crafter-build from the running executable's path.
     export CRAFTER_API fs::path GetCrafterBuildHome();
+    // Wildcard name matching ('*', '?') shared by the test and lint verbs.
+    bool MatchGlob(std::string_view glob, std::string_view name);
+    // Empty `globs` matches everything.
+    bool MatchAny(std::span<const std::string> globs, std::string_view name);
 }

interfaces/Crafter.Build-Progress.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"

interfaces/Crafter.Build-Shader.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"

interfaces/Crafter.Build-Test.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module;
 #include "Crafter.Build-Api.h"
@@ -32,7 +32,7 @@ export namespace Crafter {
         Configuration* parent;
         std::size_t index;
 
-        Test& test() const { return parent->tests[index]; }
+        Test& Ref() const { return parent->tests[index]; }
 
         // Override the path the test's sources resolve against. Defaults to
         // "./" (project root, where tests/<name>/main.cpp lives). Override
@@ -59,7 +59,7 @@ export namespace Crafter {
 
     struct RunTestsOptions {
         std::vector<std::string> globs;
-        int jobs = 0;
+        std::int32_t jobs = 0;
         std::optional<std::chrono::seconds> timeoutOverride;
         bool listOnly = false;
         // Single-target run: only tests whose Configuration::target matches
@@ -76,11 +76,11 @@ export namespace Crafter {
     };
 
     struct TestSummary {
-        int passed = 0;
+        std::int32_t passed = 0;
-        int failed = 0;
+        std::int32_t failed = 0;
-        int crashed = 0;
+        std::int32_t crashed = 0;
-        int timedOut = 0;
+        std::int32_t timedOut = 0;
-        int skipped = 0;
+        std::int32_t skipped = 0;
         std::vector<TestResult> results;
         bool AllPassed() const { return failed == 0 && crashed == 0 && timedOut == 0; }
     };

interfaces/Crafter.Build.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 export module Crafter.Build;
 export import :Clang;
@@ -8,5 +8,6 @@ export import :Implementation;
 export import :Shader;
 export import :External;
 export import :Test;
+export import :Lint;
 export import :Progress;
 export import :Asset;

lint-rules.h

@@ -0,0 +1,858 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+#pragma once
+
+// This repo's house-style lint rules. Deliberately project-local — the rule
+// set is NOT part of the crafter-build library, so downstream consumers are
+// never nudged toward one team's style. Include from project.cpp AFTER
+// `import std;` and `import Crafter.Build;` (the header uses both and has no
+// includes of its own), then call AddProjectLintRules(cfg).
+//
+// Report-only rules are registered first so their file:line numbers always
+// match the on-disk file; transforms run last because each one sees the
+// previous transform's output, which can shift line numbers.
+//
+// All detection runs on ctx.CommentStripped() — comments and string/char
+// literal bodies are blanked to spaces with newlines preserved, so byte
+// offsets and line numbers in the stripped text are valid in ctx.content.
+// Transforms use that property directly: find in stripped, edit in content.
+
+namespace ProjectLint {
+
+inline bool IsCppFile(const Crafter::LintContext& ctx) {
+    std::string ext = ctx.file.extension().string();
+    return ext == ".cpp" || ext == ".cppm" || ext == ".h";
+}
+
+inline std::vector<std::string_view> Lines(std::string_view text) {
+    std::vector<std::string_view> lines;
+    std::size_t start = 0;
+    while (start <= text.size()) {
+        std::size_t end = text.find('\n', start);
+        if (end == std::string_view::npos) {
+            if (start < text.size()) lines.push_back(text.substr(start));
+            break;
+        }
+        lines.push_back(text.substr(start, end - start));
+        start = end + 1;
+    }
+    return lines;
+}
+
+inline std::string_view Trim(std::string_view s) {
+    while (!s.empty() && (s.front() == ' ' || s.front() == '\t' || s.front() == '\r')) s.remove_prefix(1);
+    while (!s.empty() && (s.back() == ' ' || s.back() == '\t' || s.back() == '\r')) s.remove_suffix(1);
+    return s;
+}
+
+inline bool IsWordChar(char c) {
+    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '_';
+}
+
+// Net '(' minus ')' on one stripped line.
+inline std::int64_t ParenDelta(std::string_view s) {
+    std::int64_t d = 0;
+    for (char c : s) {
+        if (c == '(') ++d;
+        if (c == ')') --d;
+    }
+    return d;
+}
+
+inline bool IsPascalCase(std::string_view name) {
+    return !name.empty() && name[0] >= 'A' && name[0] <= 'Z' && !name.contains('_');
+}
+
+inline bool IsCamelCase(std::string_view name) {
+    // One trailing underscore is the member-shadowing-a-keyword convention
+    // (requires_, label_) — allowed.
+    if (name.ends_with('_')) name.remove_suffix(1);
+    return !name.empty() && ((name[0] >= 'a' && name[0] <= 'z') || name[0] == '_') && name.find('_', 1) == std::string_view::npos;
+}
+
+// The identifier ending right before position `pos` (exclusive), or empty.
+inline std::string_view WordBefore(std::string_view s, std::size_t pos) {
+    std::size_t end = pos;
+    while (end > 0 && (s[end - 1] == ' ' || s[end - 1] == '\t')) --end;
+    std::size_t begin = end;
+    while (begin > 0 && (IsWordChar(s[begin - 1]) || s[begin - 1] == '~')) --begin;
+    return s.substr(begin, end - begin);
+}
+
+inline void AddProjectLintRules(Crafter::Configuration& cfg) {
+    using Crafter::LintContext;
+
+    // ---------------- report-only rules ----------------
+
+    // License header: SPDX identifier on line 1, copyright on line 2, blank
+    // line 3.
+    cfg.AddLintRule("spdx-header", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        if (!ctx.Line(1).starts_with("// SPDX-License-Identifier:")) {
+            ctx.Report(1, "first line must be // SPDX-License-Identifier: ...");
+        }
+        if (!ctx.Line(2).starts_with("// SPDX-FileCopyrightText:")) {
+            ctx.Report(2, "second line must be // SPDX-FileCopyrightText: ...");
+        }
+        if (ctx.lines.size() >= 3 && !Trim(ctx.Line(3)).empty()) {
+            ctx.Report(3, "third line must be blank (separates the license header)");
+        }
+    });
+
+    cfg.AddLintRule("no-tabs", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {
+            if (ctx.Line(n).contains('\t')) ctx.Report(n, "tab character (use spaces)");
+        }
+    });
+
+    // Naming: functions/types PascalCase, variables camelCase, statics and
+    // namespace-scope globals PascalCase. A line-based scope tracker decides
+    // whether a declaration sits at namespace scope (global) or inside a
+    // function/type (local/member). Heuristic by nature — report-only.
+    cfg.AddLintRule("naming", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        std::vector<std::string_view> lines = Lines(ctx.CommentStripped());
+
+        enum class Scope { Namespace, Type, Function, Other };
+        std::vector<Scope> stack;
+        auto currentScope = [&]() { return stack.empty() ? Scope::Namespace : stack.back(); };
+
+        static const std::regex typeDecl(R"(\b(?:class|struct|union)\s+(?:CRAFTER_API\s+)?([A-Za-z_]\w*))");
+        static const std::regex enumDecl(R"(\benum\s+(?:class\s+|struct\s+)?([A-Za-z_]\w*))");
+        static const std::regex usingDecl(R"(^\s*using\s+([A-Za-z_]\w*)\s*=)");
+        static const std::regex varDecl(
+            R"(^\s*((?:static|constexpr|const|inline|mutable|thread_local|export|CRAFTER_API)\s+)*)"
+            R"((?:std::)?[A-Za-z_][\w:]*(?:<[^;={]*>)?(?:\s*[&*])*\s+([A-Za-z_]\w*)\s*(=|;|\{))");
+        static const std::unordered_set<std::string_view> keywords = {
+            "if", "for", "while", "switch", "catch", "return", "else", "do", "case", "goto",
+            "new", "delete", "throw", "using", "namespace", "template", "typedef", "friend",
+            "public", "private", "protected", "class", "struct", "enum", "union", "import",
+            "module", "export", "break", "continue", "co_return", "co_await", "co_yield",
+            "sizeof", "alignof", "decltype", "static_assert", "operator", "try", "requires",
+        };
+
+        // Cumulative paren depth at the start of each line: declaration and
+        // function checks only run at depth 0, so wrapped parameter lists and
+        // continuation lines (`) {` closers) never look like declarations.
+        std::int64_t parenDepth = 0;
+        for (std::size_t i = 0; i < lines.size(); ++i) {
+            std::string_view trimmed = Trim(lines[i]);
+            std::string lineStr(lines[i]);
+            std::smatch m;
+            bool atDepth0 = parenDepth == 0;
+            parenDepth = std::max<std::int64_t>(0, parenDepth + ParenDelta(lines[i]));
+
+            if (!trimmed.starts_with('#') && atDepth0) {
+                // Type / alias names must be PascalCase.
+                if (std::regex_search(lineStr, m, typeDecl) || std::regex_search(lineStr, m, enumDecl)) {
+                    std::string name = m[1].str();
+                    if (!keywords.contains(name) && !IsPascalCase(name)) {
+                        ctx.Report(i + 1, std::format("type '{}' should be PascalCase", name));
+                    }
+                }
+                if (std::regex_search(lineStr, m, usingDecl) && !IsPascalCase(m[1].str())) {
+                    ctx.Report(i + 1, std::format("type alias '{}' should be PascalCase", m[1].str()));
+                }
+
+                // Function definitions: identifier before the first '(' on a
+                // line that ends where a body opens or closes — a multi-line
+                // def's trailing '{' or a one-liner's trailing '}'. Statement
+                // calls with inline lambda arguments look similar
+                // (`bool x = std::any_of(..., [](T v) { ... });`) but end in
+                // ';' and/or carry '=' before the name — both excluded.
+                // Lambdas ("](") and control keywords are skipped; ctors/
+                // dtors pass the Pascal check by construction; `main` and
+                // operators exempt.
+                std::size_t bodyBrace = trimmed.find('{');
+                bool functionShaped = trimmed.ends_with('{') || trimmed.ends_with('}');
+                if (functionShaped && currentScope() != Scope::Function && !trimmed.starts_with("return")) {
+                    std::size_t paren = trimmed.find('(');
+                    if (paren != std::string_view::npos && paren > 0 && paren < bodyBrace) {
+                        std::string_view name = WordBefore(trimmed, paren);
+                        char before = trimmed[paren - 1];
+                        bool looksLikeDef = !name.empty() && IsWordChar(before)
+                            && !keywords.contains(name) && name != "main"
+                            && !name.starts_with('~');
+                        // Require a type token before the name (or a
+                        // qualified Class::Name), with no '=' in front —
+                        // plain calls and initializations don't match.
+                        if (looksLikeDef) {
+                            std::size_t nameStart = trimmed.rfind(name, paren);
+                            std::string_view prefix = Trim(trimmed.substr(0, nameStart));
+                            looksLikeDef = !prefix.empty() && !prefix.contains('=')
+                                && (IsWordChar(prefix.back()) || prefix.back() == '>'
+                                    || prefix.back() == '*' || prefix.back() == '&'
+                                    || prefix.ends_with("::"));
+                        }
+                        if (looksLikeDef && !IsPascalCase(name)) {
+                            ctx.Report(i + 1, std::format("function '{}' should be PascalCase", name));
+                        }
+                    }
+                }
+
+                // Variable declarations: camelCase locally, PascalCase for
+                // statics and namespace-scope globals.
+                if (std::regex_search(lineStr, m, varDecl)) {
+                    std::string name = m[2].str();
+                    std::string_view typeToken = Trim(std::string_view(lineStr).substr(0, static_cast<std::size_t>(m.position(2))));
+                    std::string_view firstWord = typeToken.substr(0, typeToken.find_first_of(" \t<"));
+                    if (!keywords.contains(firstWord) && !keywords.contains(name)) {
+                        bool isStatic = lineStr.contains("static ");
+                        // constexpr variables are compile-time constants —
+                        // constant naming (PascalCase) like statics/globals.
+                        bool isConstexpr = lineStr.contains("constexpr ");
+                        bool global = currentScope() == Scope::Namespace;
+                        if ((isStatic || global || isConstexpr) && !IsPascalCase(name)) {
+                            ctx.Report(i + 1, std::format("{} '{}' should be PascalCase",
+                                                          isStatic ? "static variable"
+                                                          : isConstexpr ? "constexpr constant"
+                                                          : "global variable", name));
+                        } else if (!isStatic && !global && !isConstexpr && !IsCamelCase(name)) {
+                            ctx.Report(i + 1, std::format("variable '{}' should be camelCase", name));
+                        }
+                    }
+                }
+            }
+
+            // Scope tracking: classify each '{' opened on this line; pop on '}'.
+            for (std::size_t c = 0; c < lines[i].size(); ++c) {
+                if (lines[i][c] == '{') {
+                    Scope kind = Scope::Other;
+                    std::string_view upTo = Trim(lines[i].substr(0, c));
+                    if (trimmed.starts_with("namespace") || upTo.contains("namespace ")) {
+                        kind = Scope::Namespace;
+                    } else if (std::regex_search(lineStr, typeDecl) || std::regex_search(lineStr, enumDecl)) {
+                        kind = Scope::Type;
+                    } else if (upTo.ends_with(')') || upTo.ends_with("const") || upTo.ends_with("noexcept")
+                               || upTo.ends_with("->") || trimmed.starts_with("extern")) {
+                        kind = Scope::Function; // function/lambda/control body — all non-global
+                    }
+                    stack.push_back(kind);
+                } else if (lines[i][c] == '}') {
+                    if (!stack.empty()) stack.pop_back();
+                }
+            }
+        }
+    });
+
+    cfg.AddLintRule("enum-class", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        std::vector<std::string_view> lines = Lines(ctx.CommentStripped());
+        static const std::regex plainEnum(R"(\benum\s+(?!class\b|struct\b)[A-Za-z_])");
+        for (std::size_t i = 0; i < lines.size(); ++i) {
+            std::string lineStr(lines[i]);
+            if (std::regex_search(lineStr, plainEnum)) {
+                ctx.Report(i + 1, "use enum class instead of plain enum");
+            }
+        }
+    });
+
+    cfg.AddLintRule("no-iostream-print", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        std::vector<std::string_view> lines = Lines(ctx.CommentStripped());
+        for (std::size_t i = 0; i < lines.size(); ++i) {
+            if (lines[i].contains("std::cout")) {
+                ctx.Report(i + 1, "use std::println instead of std::cout");
+            } else if (lines[i].contains("std::cerr") && lines[i].contains("<<")) {
+                ctx.Report(i + 1, "use std::println(std::cerr, ...) instead of streaming to std::cerr");
+            }
+        }
+    });
+
+    // Prefer std::string / std::string_view over char*. OS interop stays:
+    // getenv returns char*, argv is char**, extern "C" prototypes mirror C.
+    cfg.AddLintRule("no-char-pointer", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        std::vector<std::string_view> lines = Lines(ctx.CommentStripped());
+        static const std::regex charPtr(R"(\bchar\s*\*)");
+        for (std::size_t i = 0; i < lines.size(); ++i) {
+            std::string lineStr(lines[i]);
+            // C-interop stays char*: argv, getenv/setenv, dlerror, C APIs fed
+            // by c_str()/data(), binary IO reinterpret_casts, extern "C"
+            // prototypes. (extern " matches with the literal body blanked.)
+            if (lineStr.contains("argv") || lineStr.contains("getenv") || lineStr.contains("setenv")
+                || lineStr.contains("dlerror") || lineStr.contains("c_str") || lineStr.contains(".data(")
+                || lineStr.contains("reinterpret_cast") || lineStr.contains("extern \"")) continue;
+            if (std::regex_search(lineStr, charPtr)) {
+                ctx.Report(i + 1, "prefer std::string / std::string_view over char*");
+            }
+        }
+    });
+
+    // String building via `+` with a literal operand → std::format. Plain
+    // `a += b` accumulation (builder pattern) stays legal. Single-line chains
+    // of simple operands (identifier / member / call chains, parenthesized
+    // groups, literals) are REWRITTEN automatically; anything the operand
+    // scanner can't prove safe — raw-string lines, ternaries, mixed
+    // operators, multi-line expressions — is reported for a human instead.
+    cfg.AddLintRule("format-concat", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        const std::string& code = ctx.CommentStripped();
+        std::vector<std::string_view> stripped = Lines(code);
+
+        // Walk one operand leftwards from `from` (exclusive). Returns the
+        // operand's begin, or npos when the shape isn't a simple postfix
+        // chain (then the whole chain bails to a report).
+        auto operandLeft = [](std::string_view s, std::size_t from) -> std::size_t {
+            std::size_t i = from;
+            while (i > 0 && (s[i - 1] == ' ' || s[i - 1] == '\t')) --i;
+            bool any = false;
+            for (;;) {
+                if (i == 0) break;
+                char c = s[i - 1];
+                if (c == ')' || c == ']') {
+                    char open = c == ')' ? '(' : '[';
+                    std::size_t depth = 0;
+                    do {
+                        --i;
+                        if (s[i] == c) ++depth;
+                        if (s[i] == open) --depth;
+                        if (depth == 0) break;
+                    } while (i > 0);
+                    if (depth != 0) return std::string_view::npos;
+                    any = true;
+                    // A group directly preceded by an identifier (or another
+                    // group) is a call/index postfix — keep consuming the
+                    // callee: `path.string()` is ONE operand, not `()`.
+                    if (i > 0 && (IsWordChar(s[i - 1]) || s[i - 1] == ')' || s[i - 1] == ']')) continue;
+                } else if (c == '"') {
+                    --i; // closing quote; interior is blanked, find the opener
+                    while (i > 0 && s[i - 1] != '"') --i;
+                    if (i == 0) return std::string_view::npos;
+                    --i;
+                    any = true;
+                } else if (IsWordChar(c)) {
+                    while (i > 0 && IsWordChar(s[i - 1])) --i;
+                    any = true;
+                } else if (c == '.' && any) {
+                    --i;
+                    continue;
+                } else if (c == ':' && i > 1 && s[i - 2] == ':' && any) {
+                    i -= 2;
+                    continue;
+                } else if (c == '>' && i > 1 && s[i - 2] == '-' && any) {
+                    i -= 2;
+                    continue;
+                } else {
+                    break;
+                }
+                // After a primary, only connectors continue the operand.
+                if (i > 0 && (s[i - 1] == '.' || (s[i - 1] == ':' && i > 1 && s[i - 2] == ':')
+                              || (s[i - 1] == '>' && i > 1 && s[i - 2] == '-'))) continue;
+                break;
+            }
+            if (!any) return std::string_view::npos;
+            // A unary operator, ternary, or other-precedence operator in
+            // front means expression structure we don't reason about — bail.
+            std::size_t b = i;
+            while (b > 0 && (s[b - 1] == ' ' || s[b - 1] == '\t')) --b;
+            if (b > 0 && std::string_view("!*&~-?:<>/%^|").contains(s[b - 1])) return std::string_view::npos;
+            return i;
+        };
+
+        // Walk one operand rightwards from `from` (inclusive). Returns one
+        // past the operand's end, or npos on bail.
+        auto operandRight = [](std::string_view s, std::size_t from) -> std::size_t {
+            std::size_t i = from;
+            while (i < s.size() && (s[i] == ' ' || s[i] == '\t')) ++i;
+            bool any = false;
+            for (;;) {
+                if (i >= s.size()) break;
+                char c = s[i];
+                if (c == '(' || c == '[') {
+                    char close = c == '(' ? ')' : ']';
+                    std::size_t depth = 0;
+                    while (i < s.size()) {
+                        if (s[i] == c) ++depth;
+                        if (s[i] == close && --depth == 0) { ++i; break; }
+                        ++i;
+                    }
+                    if (depth != 0) return std::string_view::npos;
+                    any = true;
+                } else if (c == '"') {
+                    ++i;
+                    while (i < s.size() && s[i] != '"') ++i;
+                    if (i >= s.size()) return std::string_view::npos;
+                    ++i;
+                    any = true;
+                } else if (IsWordChar(c)) {
+                    while (i < s.size() && IsWordChar(s[i])) ++i;
+                    any = true;
+                } else if (any && c == '.') {
+                    ++i;
+                    continue;
+                } else if (any && c == ':' && i + 1 < s.size() && s[i + 1] == ':') {
+                    i += 2;
+                    continue;
+                } else if (any && c == '-' && i + 1 < s.size() && s[i + 1] == '>') {
+                    i += 2;
+                    continue;
+                } else {
+                    break;
+                }
+                if (i < s.size() && (s[i] == '(' || s[i] == '[' || s[i] == '.'
+                                     || (s[i] == ':' && i + 1 < s.size() && s[i + 1] == ':')
+                                     || (s[i] == '-' && i + 1 < s.size() && s[i + 1] == '>'))) continue;
+                break;
+            }
+            return any ? i : std::string_view::npos;
+        };
+
+        struct Edit { std::size_t begin; std::size_t end; std::string replacement; };
+        std::vector<Edit> edits; // offsets into ctx.content
+        std::size_t lineStart = 0;
+        for (std::size_t li = 0; li < stripped.size(); ++li) {
+            std::string_view line = stripped[li];
+            std::size_t lineOff = lineStart;
+            lineStart += line.size() + 1;
+            std::string_view trimmed = Trim(line);
+            if (trimmed.starts_with('#')) continue;
+            // Raw strings defeat the comment stripper's quote tracking; any
+            // literal-+ pattern on such a line is a manual fix.
+            bool hasRaw = std::string_view(ctx.content).substr(lineOff, line.size()).contains("R\"");
+
+            std::size_t searchFrom = 0;
+            while (searchFrom < line.size()) {
+                // A candidate `+` that isn't ++ / += and touches a literal.
+                std::size_t plus = line.find('+', searchFrom);
+                if (plus == std::string_view::npos) break;
+                searchFrom = plus + 1;
+                if (plus + 1 < line.size() && (line[plus + 1] == '+' || line[plus + 1] == '=')) { ++searchFrom; continue; }
+                if (plus > 0 && line[plus - 1] == '+') continue;
+                std::size_t leftEnd = plus;
+                while (leftEnd > 0 && (line[leftEnd - 1] == ' ' || line[leftEnd - 1] == '\t')) --leftEnd;
+                std::size_t rightBegin = plus + 1;
+                while (rightBegin < line.size() && (line[rightBegin] == ' ' || line[rightBegin] == '\t')) ++rightBegin;
+                bool literalAdjacent = (leftEnd > 0 && line[leftEnd - 1] == '"')
+                    || (rightBegin < line.size() && line[rightBegin] == '"');
+                if (!literalAdjacent) continue;
+                if (hasRaw) {
+                    ctx.Report(li + 1, "use std::format instead of string concatenation with + (raw-string line, fix manually)");
+                    break;
+                }
+
+                // Expand to the full chain: operands joined by `+`.
+                std::size_t chainBegin = operandLeft(line, plus);
+                std::size_t chainEnd = operandRight(line, plus + 1);
+                bool bail = chainBegin == std::string_view::npos || chainEnd == std::string_view::npos;
+                while (!bail) {
+                    std::size_t b = chainBegin;
+                    while (b > 0 && (line[b - 1] == ' ' || line[b - 1] == '\t')) --b;
+                    if (b > 0 && line[b - 1] == '+' && !(b > 1 && line[b - 2] == '+')) {
+                        std::size_t prev = operandLeft(line, b - 1);
+                        if (prev == std::string_view::npos) { bail = true; break; }
+                        chainBegin = prev;
+                    } else break;
+                }
+                while (!bail) {
+                    std::size_t e = chainEnd;
+                    while (e < line.size() && (line[e] == ' ' || line[e] == '\t')) ++e;
+                    if (e < line.size() && line[e] == '+' && !(e + 1 < line.size() && (line[e + 1] == '+' || line[e + 1] == '='))) {
+                        std::size_t next = operandRight(line, e + 1);
+                        if (next == std::string_view::npos) { bail = true; break; }
+                        chainEnd = next;
+                    } else break;
+                }
+                if (bail) {
+                    ctx.Report(li + 1, "use std::format instead of string concatenation with + (not auto-fixable)");
+                    break;
+                }
+
+                // Split the chain at depth-0 '+' into parts; literals feed the
+                // format string, everything else becomes an argument.
+                std::string_view chain = line.substr(chainBegin, chainEnd - chainBegin);
+                std::string_view rawChain = std::string_view(ctx.content).substr(lineOff + chainBegin, chainEnd - chainBegin);
+                std::string fmt;
+                std::vector<std::string_view> args;
+                std::size_t partBegin = 0;
+                std::int64_t depth = 0;
+                bool inLit = false;
+                for (std::size_t p = 0; p <= chain.size(); ++p) {
+                    if (p < chain.size()) {
+                        char c = chain[p];
+                        if (c == '"') inLit = !inLit;
+                        if (inLit) continue;
+                        if (c == '(' || c == '[') ++depth;
+                        if (c == ')' || c == ']') --depth;
+                        if (!(c == '+' && depth == 0)) continue;
+                    }
+                    std::string_view part = Trim(chain.substr(partBegin, p - partBegin));
+                    std::string_view rawPart = Trim(rawChain.substr(partBegin, p - partBegin));
+                    if (part.starts_with('"') && part.ends_with('"') && part.size() >= 2
+                        && std::count(part.begin(), part.end(), '"') == 2) {
+                        for (char c : rawPart.substr(1, rawPart.size() - 2)) {
+                            fmt += c;
+                            if (c == '{') fmt += '{';
+                            if (c == '}') fmt += '}';
+                        }
+                    } else if (part.contains('"') && part.contains('+')) {
+                        bail = true; // nested concat inside an operand — human territory
+                        break;
+                    } else {
+                        fmt += "{}";
+                        args.push_back(rawPart);
+                    }
+                    partBegin = p + 1;
+                }
+                if (bail || args.empty()) {
+                    ctx.Report(li + 1, "use std::format instead of string concatenation with + (not auto-fixable)");
+                    break;
+                }
+                std::string replacement = std::format("std::format(\"{}\"", fmt);
+                for (std::string_view a : args) replacement += std::format(", {}", a);
+                replacement += ")";
+                edits.push_back({lineOff + chainBegin, lineOff + chainEnd, std::move(replacement)});
+                searchFrom = chainEnd;
+            }
+        }
+        if (edits.empty()) return;
+        std::string out = ctx.content;
+        std::sort(edits.begin(), edits.end(), [](const Edit& a, const Edit& b) { return a.begin > b.begin; });
+        for (const Edit& e : edits) out.replace(e.begin, e.end - e.begin, e.replacement);
+        ctx.SetContent(std::move(out));
+    });
+
+    // ---------------- transforms (auto-fixed by `crafter-build format`) ----------------
+
+    // short/int/long → fixed-width types. Lines mentioning main/argc/argv or
+    // extern "C" keep their C-conventional ints.
+    cfg.AddLintRule("fixed-width-types", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        const std::string& code = ctx.CommentStripped();
+        struct Rep { std::size_t pos; std::size_t len; std::string to; };
+        std::vector<Rep> reps;
+        // Builtin integer type specifiers combine in any order (`unsigned
+        // long`, `long unsigned int`, ...), so match whole RUNS of these
+        // keywords and classify the run, rather than the words one by one.
+        static const std::unordered_set<std::string_view> IntWords = {
+            "unsigned", "signed", "short", "long", "int", "char",
+        };
+        std::size_t lineStart = 0;
+        while (lineStart <= code.size()) {
+            std::size_t lineEnd = code.find('\n', lineStart);
+            if (lineEnd == std::string::npos) lineEnd = code.size();
+            std::string_view line(code.data() + lineStart, lineEnd - lineStart);
+            // `int main` / argc / argv keep their C-conventional type; so do
+            // extern "C" prototypes (the literal body is blanked in the
+            // stripped text, so match `extern "`).
+            bool exempt = line.contains("int main") || line.contains("argc") || line.contains("argv")
+                || line.contains("extern \"");
+            std::size_t pos = 0;
+            while (!exempt && pos < line.size()) {
+                if (!IsWordChar(line[pos])) { ++pos; continue; }
+                std::size_t wordEnd = pos;
+                while (wordEnd < line.size() && IsWordChar(line[wordEnd])) ++wordEnd;
+                if (!IntWords.contains(line.substr(pos, wordEnd - pos))) { pos = wordEnd; continue; }
+
+                // Extend the run over consecutive specifier keywords.
+                std::size_t runBegin = pos;
+                std::size_t runEnd = wordEnd;
+                bool hasUnsigned = false;
+                bool hasSigned = false;
+                bool hasShort = false;
+                bool hasChar = false;
+                bool hasLong = false;
+                std::string_view nextWord;
+                for (;;) {
+                    std::string_view word = line.substr(pos, wordEnd - pos);
+                    if (word == "unsigned") hasUnsigned = true;
+                    else if (word == "signed") hasSigned = true;
+                    else if (word == "short") hasShort = true;
+                    else if (word == "char") hasChar = true;
+                    else if (word == "long") hasLong = true;
+                    runEnd = wordEnd;
+                    pos = wordEnd;
+                    while (pos < line.size() && (line[pos] == ' ' || line[pos] == '\t')) ++pos;
+                    wordEnd = pos;
+                    while (wordEnd < line.size() && IsWordChar(line[wordEnd])) ++wordEnd;
+                    nextWord = line.substr(pos, wordEnd - pos);
+                    if (!IntWords.contains(nextWord)) break;
+                }
+                pos = runEnd;
+
+                // Bare `char` is text, not an integer — only signed/unsigned
+                // char is byte arithmetic. `long double` is a floating type.
+                if (hasChar && !hasUnsigned && !hasSigned) continue;
+                if (nextWord == "double") continue;
+
+                std::string_view width = hasChar ? "8" : hasShort ? "16" : hasLong ? "64" : "32";
+                reps.push_back({lineStart + runBegin, runEnd - runBegin,
+                                std::format("std::{}int{}_t", hasUnsigned ? "u" : "", width)});
+            }
+            lineStart = lineEnd + 1;
+        }
+        if (reps.empty()) return;
+        std::string out = ctx.content;
+        std::sort(reps.begin(), reps.end(), [](const Rep& a, const Rep& b) { return a.pos > b.pos; });
+        for (const Rep& r : reps) out.replace(r.pos, r.len, r.to);
+        ctx.SetContent(std::move(out));
+    });
+
+    // One declaration per statement. Auto-splits the simple initialized form
+    // `Type a = x, b = y;`; anything with pointers/references, parens, or
+    // templates in the declarators is only reported (splitting `int* a, b;`
+    // would change b's type).
+    cfg.AddLintRule("single-declaration", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        std::vector<std::string_view> stripped = Lines(ctx.CommentStripped());
+        // The declarator char class excludes quotes: string-literal bodies are
+        // blanked in the stripped text, so reconstructing them would corrupt
+        // the file — those lines are left alone.
+        static const std::regex simpleMulti(
+            R"(^(\s*)((?:std::)?[A-Za-z_][\w:]*)\s+([A-Za-z_]\w*\s*=\s*[^,;()<>*&"]+(?:,\s*[A-Za-z_]\w*\s*=\s*[^,;()<>*&"]+)+);\s*$)");
+        std::string out;
+        bool changed = false;
+        for (std::size_t i = 0; i < stripped.size(); ++i) {
+            std::string lineStr(stripped[i]);
+            std::smatch m;
+            std::string_view raw = i + 1 <= ctx.lines.size() ? ctx.Line(i + 1) : std::string_view{};
+            if (!raw.contains("//") && !ctx.Suppressed("single-declaration", i + 1)
+                && std::regex_match(lineStr, m, simpleMulti)) {
+                std::string indent = m[1].str(), type = m[2].str(), decls = m[3].str();
+                std::size_t start = 0;
+                bool first = true;
+                while (start < decls.size()) {
+                    std::size_t comma = decls.find(',', start);
+                    std::string_view d = Trim(std::string_view(decls).substr(start, comma == std::string::npos ? std::string::npos : comma - start));
+                    if (!first) out += '\n';
+                    out += std::format("{}{} {};", indent, type, d);
+                    first = false;
+                    if (comma == std::string::npos) break;
+                    start = comma + 1;
+                }
+                changed = true;
+            } else {
+                out += raw;
+            }
+            if (i + 1 < stripped.size() || ctx.content.ends_with('\n')) out += '\n';
+        }
+        if (changed) ctx.SetContent(std::move(out));
+    });
+
+    // K&R braces: `{` on its own line after a `)`/else/do/try header joins
+    // onto the header line. Standalone scope blocks (previous line ends with
+    // `;`, `{`, a comment, …) are intentional and stay.
+    cfg.AddLintRule("brace-style", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        std::vector<std::string_view> stripped = Lines(ctx.CommentStripped());
+        std::vector<std::string> outLines;
+        outLines.reserve(ctx.lines.size());
+        bool changed = false;
+        for (std::size_t i = 0; i < ctx.lines.size(); ++i) {
+            std::string_view trimmed = Trim(stripped[i]);
+            if (trimmed == "{" && !outLines.empty()) {
+                std::string_view prevTrim = i > 0 ? Trim(stripped[i - 1]) : std::string_view{};
+                bool headerBefore = prevTrim.ends_with(')') || prevTrim == "else" || prevTrim == "do" || prevTrim == "try";
+                bool hasComment = ctx.Line(i + 1).contains("//") || (i > 0 && ctx.Line(i).contains("//"));
+                bool suppressed = ctx.Suppressed("brace-style", i) || ctx.Suppressed("brace-style", i + 1);
+                if (headerBefore && !hasComment && !suppressed) {
+                    std::string& prev = outLines.back();
+                    while (!prev.empty() && (prev.back() == ' ' || prev.back() == '\t')) prev.pop_back();
+                    prev += " {";
+                    changed = true;
+                    continue;
+                }
+            }
+            outLines.emplace_back(ctx.Line(i + 1));
+        }
+        if (!changed) return;
+        std::string out;
+        for (std::size_t i = 0; i < outLines.size(); ++i) {
+            out += outLines[i];
+            if (i + 1 < outLines.size() || ctx.content.ends_with('\n')) out += '\n';
+        }
+        ctx.SetContent(std::move(out));
+    });
+
+    // Single-statement if bodies join onto the if line: `if (x)\n  y;` →
+    // `if (x) y;` — when the condition's parens balance on one line, the body
+    // is one `;`-terminated statement, neither line carries a comment, and
+    // the joined line stays ≤ 250 columns.
+    cfg.AddLintRule("if-single-line", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        std::vector<std::string_view> stripped = Lines(ctx.CommentStripped());
+        static const std::regex ifHeader(R"(^\s*(?:\}?\s*else\s+)?if\s*\(.*\)\s*$)");
+        std::vector<std::string> outLines;
+        bool changed = false;
+        for (std::size_t i = 0; i < ctx.lines.size(); ++i) {
+            std::string lineStr(stripped[i]);
+            if (i + 1 < ctx.lines.size() && std::regex_match(lineStr, ifHeader) && ParenDelta(stripped[i]) == 0) {
+                std::string_view body = Trim(stripped[i + 1]);
+                bool joinable = !body.empty() && body != "{" && !body.starts_with("if") && body.ends_with(';')
+                    && !ctx.Line(i + 1).contains("//") && !ctx.Line(i + 2).contains("//")
+                    && !ctx.Suppressed("if-single-line", i + 1) && !ctx.Suppressed("if-single-line", i + 2);
+                std::string joined = std::string(ctx.Line(i + 1));
+                while (!joined.empty() && (joined.back() == ' ' || joined.back() == '\t')) joined.pop_back();
+                joined += " ";
+                joined += Trim(ctx.Line(i + 2));
+                if (joinable && joined.size() <= 250) {
+                    outLines.push_back(std::move(joined));
+                    ++i; // consume the body line
+                    changed = true;
+                    continue;
+                }
+            }
+            outLines.emplace_back(ctx.Line(i + 1));
+        }
+        if (!changed) return;
+        std::string out;
+        for (std::size_t i = 0; i < outLines.size(); ++i) {
+            out += outLines[i];
+            if (i + 1 < outLines.size() || ctx.content.ends_with('\n')) out += '\n';
+        }
+        ctx.SetContent(std::move(out));
+    });
+
+    // Wrapped call arguments join back onto one line when the whole
+    // expression fits in 250 columns. Lambda bodies (lines ending `{`),
+    // comments, raw strings, and preprocessor lines are left alone.
+    // Operator-style continuations (next line starts with && / || / |) join
+    // under the same length limit.
+    cfg.AddLintRule("wrap-join", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        // Fixpoint loop: a join can enable another (joining an inner paren
+        // wrap balances the line an operator continuation hangs off), so one
+        // pass is not idempotent. Iterate until a pass changes nothing; the
+        // cap is a safety net — joins strictly reduce the line count, so
+        // termination is guaranteed anyway.
+        for (std::int32_t pass = 0; pass < 16; ++pass) {
+        std::vector<std::string_view> stripped = Lines(ctx.CommentStripped());
+        std::vector<std::string> outLines;
+        bool changed = false;
+        for (std::size_t i = 0; i < ctx.lines.size(); ++i) {
+            std::string_view trimmed = Trim(stripped[i]);
+            std::int64_t delta = ParenDelta(stripped[i]);
+            bool candidate = delta > 0 && !trimmed.empty() && !trimmed.starts_with('#')
+                && !trimmed.ends_with('{') && !ctx.Line(i + 1).contains("//") && !ctx.Line(i + 1).contains("R\"");
+            if (candidate) {
+                std::string joined(ctx.Line(i + 1));
+                std::size_t j = i + 1;
+                bool ok = true;
+                while (delta > 0 && j < ctx.lines.size() && j - i <= 4) {
+                    std::string_view next = Trim(stripped[j]);
+                    // A `{`-ending line is fine when it closes the expression
+                    // (a control header's `) {`); mid-expression it means a
+                    // lambda body starts — leave those wrapped.
+                    bool closes = delta + ParenDelta(stripped[j]) <= 0;
+                    if (next.empty() || (next.ends_with('{') && !closes)
+                        || ctx.Line(j + 1).contains("//") || ctx.Line(j + 1).contains("R\"")) {
+                        ok = false;
+                        break;
+                    }
+                    while (!joined.empty() && (joined.back() == ' ' || joined.back() == '\t')) joined.pop_back();
+                    std::string_view fragment = Trim(ctx.Line(j + 1));
+                    // No separator right after an opening paren or before a
+                    // closing one — joining must not manufacture `( x` / `x )`.
+                    if (!joined.ends_with('(') && !fragment.starts_with(')') && !fragment.starts_with(',')) joined += " ";
+                    joined += fragment;
+                    delta += ParenDelta(stripped[j]);
+                    ++j;
+                }
+                for (std::size_t l = i + 1; ok && l <= j; ++l) ok = !ctx.Suppressed("wrap-join", l);
+                if (ok && delta <= 0 && joined.size() <= 250) {
+                    outLines.push_back(std::move(joined));
+                    i = j - 1; // consumed through line j-1 (0-based i)
+                    changed = true;
+                    continue;
+                }
+            } else if (delta == 0 && i + 1 < ctx.lines.size() && !trimmed.starts_with('#')
+                       && !ctx.Line(i + 1).contains("//") && !ctx.Line(i + 1).contains("R\"")) {
+                auto isOpStart = [](std::string_view s) {
+                    return s.starts_with("&&") || s.starts_with("||") || s.starts_with("| ");
+                };
+                // Operator-style continuation chain (`a\n && b\n && c`).
+                // Joined when the WHOLE chain stays within 250 columns —
+                // longer conditions legitimately wrap. Same mechanics as the
+                // paren join: chain lines must be comment-free, raw-string
+                // free, and paren-balanced.
+                if (isOpStart(Trim(stripped[i + 1])) && !isOpStart(trimmed)) {
+                    std::string joined(ctx.Line(i + 1));
+                    std::size_t j = i + 1;
+                    bool ok = true;
+                    while (j < ctx.lines.size() && isOpStart(Trim(stripped[j]))) {
+                        if (ParenDelta(stripped[j]) != 0 || ctx.Line(j + 1).contains("//") || ctx.Line(j + 1).contains("R\"")) {
+                            ok = false;
+                            break;
+                        }
+                        while (!joined.empty() && (joined.back() == ' ' || joined.back() == '\t')) joined.pop_back();
+                        joined += " ";
+                        joined += Trim(ctx.Line(j + 1));
+                        ++j;
+                    }
+                    for (std::size_t l = i + 1; ok && l <= j; ++l) ok = !ctx.Suppressed("wrap-join", l);
+                    if (ok && joined.size() <= 250) {
+                        outLines.push_back(std::move(joined));
+                        i = j - 1; // consumed the chain
+                        changed = true;
+                        continue;
+                    }
+                }
+            }
+            outLines.emplace_back(ctx.Line(i + 1));
+        }
+        if (!changed) return;
+        std::string out;
+        for (std::size_t i = 0; i < outLines.size(); ++i) {
+            out += outLines[i];
+            if (i + 1 < outLines.size() || ctx.content.ends_with('\n')) out += '\n';
+        }
+        ctx.SetContent(std::move(out));
+        }
+    });
+
+    // No space padding inside parens: `( x` / `x )` → `(x` / `x)`. Only
+    // intra-line (a line legitimately ends with '(' when a call wraps);
+    // string/comment interiors are excluded via the stripped text.
+    cfg.AddLintRule("paren-spacing", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        const std::string& code = ctx.CommentStripped();
+        std::vector<std::pair<std::size_t, std::size_t>> cuts; // [begin, end) spans of spaces to delete
+        for (std::size_t i = 0; i < code.size(); ++i) {
+            if (code[i] == '(' ) {
+                std::size_t j = i + 1;
+                while (j < code.size() && code[j] == ' ') ++j;
+                if (j > i + 1 && j < code.size() && code[j] != '\n' && code[j] != '\r') cuts.push_back({i + 1, j});
+            } else if (code[i] == ')') {
+                std::size_t j = i;
+                while (j > 0 && code[j - 1] == ' ') --j;
+                // Only single-space padding: multi-space runs are usually
+                // deliberate alignment columns.
+                if (j == i - 1 && j > 0 && code[j - 1] != '\n' && code[j - 1] != ',') cuts.push_back({j, i});
+            }
+        }
+        if (cuts.empty()) return;
+        std::string out = ctx.content;
+        for (auto it = cuts.rbegin(); it != cuts.rend(); ++it) out.erase(it->first, it->second - it->first);
+        ctx.SetContent(std::move(out));
+    });
+
+    cfg.AddLintRule("trim-trailing-ws", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        std::string out;
+        out.reserve(ctx.content.size());
+        for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {
+            std::string_view line = ctx.Line(n);
+            // Byte fidelity on CRLF files: peel the \r, trim, put it back.
+            bool crlf = line.ends_with('\r');
+            if (crlf) line.remove_suffix(1);
+            while (line.ends_with(' ') || line.ends_with('\t')) line.remove_suffix(1);
+            out += line;
+            if (crlf) out += '\r';
+            // The last line only had a newline if the file ended with one —
+            // preserve that byte exactly so this rule doesn't shadow
+            // final-newline.
+            if (n < ctx.lines.size() || ctx.content.ends_with('\n')) out += '\n';
+        }
+        ctx.SetContent(std::move(out));
+    });
+
+    cfg.AddLintRule("final-newline", [](LintContext& ctx) {
+        if (!IsCppFile(ctx)) return;
+        if (!ctx.content.empty() && !ctx.content.ends_with('\n')) {
+            ctx.SetContent(ctx.content + '\n');
+        }
+    });
+}
+
+} // namespace ProjectLint

project.cpp

@@ -1,8 +1,9 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
+#include "lint-rules.h"
 namespace fs = std::filesystem;
 using namespace Crafter;
 
@@ -17,22 +18,22 @@ extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> a
         .args = depArgs,
     });
 
-    static auto crafterBuildLib = std::make_unique<Configuration>();
+    static auto CrafterBuildLib = std::make_unique<Configuration>();
-    crafterBuildLib->path = "./";
+    CrafterBuildLib->path = "./";
-    crafterBuildLib->name = "crafter.build-lib";
+    CrafterBuildLib->name = "crafter.build-lib";
-    crafterBuildLib->outputName = "crafter-build";
+    CrafterBuildLib->outputName = "crafter-build";
-    ApplyStandardArgs(*crafterBuildLib, args);
+    ApplyStandardArgs(*CrafterBuildLib, args);
     // Windows builds (native msvc via build.cmd or cross-compiled mingw from
     // Linux) need a DLL + import lib + launcher exe so LoadProject can
     // compile project.cpp against a stable ABI boundary. Linux is monolithic.
-    crafterBuildLib->type = (crafterBuildLib->target == "x86_64-w64-mingw32" || crafterBuildLib->target == "x86_64-pc-windows-msvc")
+    CrafterBuildLib->type = (CrafterBuildLib->target == "x86_64-w64-mingw32" || CrafterBuildLib->target == "x86_64-pc-windows-msvc")
         ? ConfigurationType::LibraryDynamic
         : ConfigurationType::LibraryStatic;
 
-    crafterBuildLib->dependencies = { math, asset };
+    CrafterBuildLib->dependencies = { math, asset };
-    crafterBuildLib->defines.push_back({"CRAFTER_BUILD_HAS_ASSET", ""});
+    CrafterBuildLib->defines.push_back({"CRAFTER_BUILD_HAS_ASSET", ""});
     {
-        std::array<fs::path, 10> interfaces = {
+        std::array<fs::path, 11> interfaces = {
             "interfaces/Crafter.Build",
             "interfaces/Crafter.Build-Shader",
             "interfaces/Crafter.Build-Platform",
@@ -41,10 +42,11 @@ extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> a
             "interfaces/Crafter.Build-External",
             "interfaces/Crafter.Build-Clang",
             "interfaces/Crafter.Build-Test",
+            "interfaces/Crafter.Build-Lint",
             "interfaces/Crafter.Build-Progress",
             "interfaces/Crafter.Build-Asset",
         };
-        std::array<fs::path, 9> implementations = {
+        std::array<fs::path, 10> implementations = {
             "implementations/Crafter.Build-Shader",
             "implementations/Crafter.Build-Platform",
             "implementations/Crafter.Build-Interface",
@@ -52,12 +54,13 @@ extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> a
             "implementations/Crafter.Build-External",
             "implementations/Crafter.Build-Clang",
             "implementations/Crafter.Build-Test",
+            "implementations/Crafter.Build-Lint",
             "implementations/Crafter.Build-Progress",
             "implementations/Crafter.Build-Asset",
         };
-        crafterBuildLib->GetInterfacesAndImplementations(interfaces, implementations);
+        CrafterBuildLib->GetInterfacesAndImplementations(interfaces, implementations);
     }
-    ExternalDependency& glslang = crafterBuildLib->externalDependencies.emplace_back();
+    ExternalDependency& glslang = CrafterBuildLib->externalDependencies.emplace_back();
     glslang.name = "glslang";
     glslang.source.url = "https://github.com/KhronosGroup/glslang.git";
     glslang.source.branch = "main";
@@ -66,7 +69,7 @@ extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> a
     // mingw cross-build: skip the standalone executable. We only consume the
     // libraries, and glslang.exe pulls in libgcc_eh which needs pthread that
     // mingw-w64 doesn't link by default.
-    if (crafterBuildLib->target == "x86_64-w64-mingw32") {
+    if (CrafterBuildLib->target == "x86_64-w64-mingw32") {
         glslang.options.push_back("-DENABLE_GLSLANG_BINARIES=OFF");
     }
     glslang.includeDirs = { "" };
@@ -78,7 +81,7 @@ extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> a
     cfg.outputName = "crafter-build";
     ApplyStandardArgs(cfg, args);
     cfg.type = ConfigurationType::Executable;
-    cfg.dependencies = { crafterBuildLib.get() };
+    cfg.dependencies = { CrafterBuildLib.get() };
     {
         std::array<fs::path, 0> interfaces = {};
         std::array<fs::path, 1> implementations = { "implementations/main" };
@@ -90,35 +93,42 @@ extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> a
     }
     if (cfg.target == "x86_64-w64-mingw32" || cfg.target == "x86_64-pc-windows-msvc") {
         // winsock for the -r wasm port probe (bind/WSAStartup).
-        crafterBuildLib->linkFlags.push_back("-lws2_32");
+        CrafterBuildLib->linkFlags.push_back("-lws2_32");
     }
 
     // Self-tests link the local crafter-build library and exercise it in
     // process. The harness (whichever crafter-build invokes `test`) compiles
     // these against the *installed* share/crafter-build .cppm files, then
-    // links each test exe against crafterBuildLib built from the local
+    // links each test exe against CrafterBuildLib built from the local
     // sources — so the code under test is whatever's in this checkout.
     // Mirrors how downstream consumers link their own libraries into tests.
     if (cfg.target == "x86_64-pc-linux-gnu") {
-        cfg.AddTest("HelloWorld").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("HelloWorld").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("StaticLib").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("StaticLib").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("ModuleInterface").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("ModuleInterface").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("DependencyLink").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("DependencyLink").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("ShaderCompile").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("ShaderCompile").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("StandardArgs").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("StandardArgs").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("TestRunnerSpec").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("TestRunnerSpec").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("VariantId").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("VariantId").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("WasiBrowserRuntime").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("WasiBrowserRuntime").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("WasmVariants").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("WasmVariants").Dependencies({ CrafterBuildLib.get() });
-        cfg.AddTest("RunSingleTestExit").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("RunSingleTestExit").Dependencies({ CrafterBuildLib.get() });
         // LoadProject dlopens the synthesized project.so, which references
         // Crafter:: symbols (HostTarget, Configuration ctors) that have to be
         // visible from the test exe — same wiring crafter-build itself uses
         // for project.so.
-        cfg.AddTest("ConcurrentCacheRace").Dependencies({ crafterBuildLib.get() })
+        cfg.AddTest("ConcurrentCacheRace").Dependencies({ CrafterBuildLib.get() })
             .LinkFlag("-Wl,--export-dynamic").LinkFlag("-ldl");
-        cfg.AddTest("ConcurrentDependencyReset").Dependencies({ crafterBuildLib.get() });
+        cfg.AddTest("ConcurrentDependencyReset").Dependencies({ CrafterBuildLib.get() });
+        cfg.AddTest("Lint").Dependencies({ CrafterBuildLib.get() });
+        cfg.AddTest("HouseRules").Dependencies({ CrafterBuildLib.get() });
     }
 
+    // Dogfood: this repo's house-style rules (see lint-rules.h). Report
+    // rules gate `crafter-build lint`; transform rules also auto-fix under
+    // `crafter-build format`.
+    ProjectLint::AddProjectLintRules(cfg);
+
     return cfg;
 }

tests/ConcurrentCacheRace/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 #include <stdlib.h>
 import std;
@@ -27,7 +27,7 @@ namespace {
         if (const char* env = std::getenv("CRAFTER_BUILD_HOME"); env && *env) {
             return env;
         }
-        for (const char* candidate : {
+        for (std::string_view candidate : {
             "/usr/local/share/crafter-build",
             "/usr/share/crafter-build",
         }) {
@@ -47,8 +47,7 @@ namespace {
 int main() {
     fs::path home = FindCrafterBuildHome();
     if (home.empty()) {
-        std::println(std::cerr,
+        std::println(std::cerr, "SKIP: no installed share/crafter-build found and CRAFTER_BUILD_HOME unset");
-            "SKIP: no installed share/crafter-build found and CRAFTER_BUILD_HOME unset");
         return 77;
     }
     setenv("CRAFTER_BUILD_HOME", home.string().c_str(), 1);
@@ -64,9 +63,9 @@ int main() {
     fs::create_directories(cacheDir);
     setenv("XDG_CACHE_HOME", cacheDir.string().c_str(), 1);
 
-    constexpr int N = 4;
+    constexpr std::int32_t N = 4;
     std::vector<fs::path> projects;
-    for (int i = 0; i < N; ++i) {
+    for (std::int32_t i = 0; i < N; ++i) {
         fs::path dir = scratch / std::format("p{}", i);
         fs::create_directories(dir);
         WriteFile(dir / "project.cpp", std::format(
@@ -89,7 +88,7 @@ int main() {
     std::array<std::string, N> errors;
     std::vector<std::thread> threads;
     threads.reserve(N);
-    for (int i = 0; i < N; ++i) {
+    for (std::int32_t i = 0; i < N; ++i) {
         threads.emplace_back([&, i]() {
             try {
                 std::array<std::string_view, 0> args = {};
@@ -101,8 +100,8 @@ int main() {
     }
     for (std::thread& t : threads) t.join();
 
-    int failures = 0;
+    std::int32_t failures = 0;
-    for (int i = 0; i < N; ++i) {
+    for (std::int32_t i = 0; i < N; ++i) {
         if (!errors[i].empty()) {
             std::println(std::cerr, "FAIL p{}: {}", i, errors[i]);
             ++failures;
@@ -112,9 +111,7 @@ int main() {
     fs::remove_all(scratch, ec);
 
     if (failures > 0) {
-        std::println(std::cerr,
+        std::println(std::cerr, "{}/{} concurrent LoadProject() invocations failed (host-cache race)", failures, N);
-            "{}/{} concurrent LoadProject() invocations failed (host-cache race)",
-            failures, N);
         return 1;
     }
     return 0;

tests/ConcurrentDependencyReset/fixture/app/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import DepMod;

tests/ConcurrentDependencyReset/fixture/deplib/DepMod-impl.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 module DepMod;
 

tests/ConcurrentDependencyReset/fixture/deplib/DepMod.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 export module DepMod;
 export int dep_value();

tests/ConcurrentDependencyReset/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
@@ -101,10 +101,7 @@ int main() {
         // reset the (cached, never-rebuilt) dependency's module flag. Before the
         // fix this was false and an intra-config waiter would have deadlocked.
         if (!dep.interfaces[0]->compiled.load()) {
-            std::println(std::cerr,
+            std::println(std::cerr, "FAIL: consumer build reset a cached dependency's module 'compiled' " "flag (issue #16 regression) — this is the state that deadlocks a " "concurrent build");
-                "FAIL: consumer build reset a cached dependency's module 'compiled' "
-                "flag (issue #16 regression) — this is the state that deadlocks a "
-                "concurrent build");
             return 1;
         }
 
@@ -115,8 +112,7 @@ int main() {
         }
         auto run = RunCommandWithTimeout(bin.string(), std::chrono::seconds(10));
         if (run.exitCode != 0 || run.timedOut || run.crashed) {
-            std::println(std::cerr, "consumer exe did not exit cleanly: exit={} output={}",
+            std::println(std::cerr, "consumer exe did not exit cleanly: exit={} output={}", run.exitCode, run.output);
-                run.exitCode, run.output);
             return 1;
         }
         if (run.output != "42") {

tests/DependencyLink/fixture/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Calc;

tests/DependencyLink/fixture/mathlib/Calc.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 export module Calc;
 import std;

tests/DependencyLink/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
@@ -44,18 +44,15 @@ int main() {
     }
     // The import resolves to the dependency's interface, not a local one.
     if (!app.implementations[0].moduleDependencies.empty()) {
-        std::println(std::cerr, "expected no local module deps, got {}",
+        std::println(std::cerr, "expected no local module deps, got {}", app.implementations[0].moduleDependencies.size());
-            app.implementations[0].moduleDependencies.size());
         return 1;
     }
     if (app.implementations[0].externalModuleDependencies.size() != 1) {
-        std::println(std::cerr, "expected 1 external module dep, got {}",
+        std::println(std::cerr, "expected 1 external module dep, got {}", app.implementations[0].externalModuleDependencies.size());
-            app.implementations[0].externalModuleDependencies.size());
         return 1;
     }
     if (app.implementations[0].externalModuleDependencies[0].first->name != "Calc") {
-        std::println(std::cerr, "expected external dep 'Calc', got '{}'",
+        std::println(std::cerr, "expected external dep 'Calc', got '{}'", app.implementations[0].externalModuleDependencies[0].first->name);
-            app.implementations[0].externalModuleDependencies[0].first->name);
         return 1;
     }
 
@@ -81,8 +78,7 @@ int main() {
 
     auto run = RunCommandWithTimeout(bin.string(), std::chrono::seconds(10));
     if (run.exitCode != 0 || run.timedOut || run.crashed) {
-        std::println(std::cerr, "exe did not exit cleanly: exit={} output={}",
+        std::println(std::cerr, "exe did not exit cleanly: exit={} output={}", run.exitCode, run.output);
-            run.exitCode, run.output);
         return 1;
     }
     if (run.output != "7") {

tests/HelloWorld/fixture/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 int main() { return 0; }

tests/HelloWorld/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;

tests/HouseRules/main.cpp

@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+
+import std;
+import Crafter.Build;
+#include "../../lint-rules.h"
+namespace fs = std::filesystem;
+using namespace Crafter;
+
+// Validates the house-style ruleset in lint-rules.h — the transforms and
+// reports this repo (and sibling repos that copy the header) rely on. Each
+// case writes a scratch file, runs ONE rule via the glob filter, and asserts
+// the findings and/or rewritten bytes.
+namespace {
+    std::int32_t Failures = 0;
+
+    void Check(bool cond, std::string_view msg) {
+        if (!cond) {
+            std::println(std::cerr, "FAIL: {}", msg);
+            ++Failures;
+        }
+    }
+
+    struct RuleRun {
+        LintSummary summary;
+        std::string text; // file content after the run
+    };
+
+    RuleRun RunRule(std::string_view content, std::string_view rule, LintMode mode) {
+        static std::int32_t Counter = 0;
+        fs::path dir = fs::temp_directory_path() / "crafter-build-house-rules" / std::format("case-{}", Counter++);
+        fs::remove_all(dir);
+        fs::create_directories(dir);
+        {
+            std::ofstream f(dir / "f.cpp", std::ios::binary | std::ios::trunc);
+            f.write(content.data(), static_cast<std::streamsize>(content.size()));
+        }
+        Configuration cfg;
+        cfg.path = dir;
+        cfg.name = "house-fixture";
+        cfg.outputName = "house-fixture";
+        cfg.target = HostTarget();
+        std::array<fs::path, 0> ifaces = {};
+        std::array<fs::path, 1> impls = { "f" };
+        cfg.GetInterfacesAndImplementations(ifaces, impls);
+        ProjectLint::AddProjectLintRules(cfg);
+        RunLintOptions opts;
+        opts.mode = mode;
+        opts.globs = { std::string(rule) };
+        RuleRun run;
+        run.summary = RunLint(cfg, opts);
+        std::ifstream f(dir / "f.cpp", std::ios::binary);
+        std::stringstream buffer;
+        buffer << f.rdbuf();
+        run.text = std::move(buffer).str();
+        return run;
+    }
+
+    bool HasFinding(const LintSummary& s, std::string_view fragment) {
+        return std::any_of(s.findings.begin(), s.findings.end(), [&](const LintFinding& f) { return f.message.contains(fragment); });
+    }
+}
+
+int main() {
+    // fixed-width-types: int/long long convert; main/argc and extern "C" stay.
+    {
+        RuleRun r = RunRule("int Foo(long long v) { int x = 5; return x; }\n" "extern \"C\" int setenv(const char* n, const char* v, int o);\n" "int main(int argc, char** argv) { return 0; }\n", "fixed-width-types", LintMode::Apply);
+        Check(r.text.contains("std::int32_t Foo(std::int64_t v) { std::int32_t x = 5;"), "fixed-width converts int and long long");
+        Check(r.text.contains("extern \"C\" int setenv"), "extern \"C\" prototype keeps int");
+        Check(r.text.contains("int main(int argc"), "main/argc keep int");
+    }
+
+    // fixed-width-types is signed/unsigned aware, in any specifier order;
+    // bare char (text) and long double (floating) are not integers.
+    {
+        RuleRun r = RunRule("void F() {\n"
+                            "    unsigned a = 1;\n"
+                            "    unsigned int b = 2;\n"
+                            "    unsigned long long c = 3;\n"
+                            "    long unsigned int d = 4;\n"
+                            "    unsigned short e = 5;\n"
+                            "    signed f = 6;\n"
+                            "    signed char g = 7;\n"
+                            "    auto h = static_cast<unsigned char>(g);\n"
+                            "    char text = 'x';\n"
+                            "    long double pi = 3.14L;\n"
+                            "}\n",
+                            "fixed-width-types", LintMode::Apply);
+        Check(r.text.contains("std::uint32_t a = 1;"), "bare unsigned -> uint32");
+        Check(r.text.contains("std::uint32_t b = 2;"), "unsigned int -> uint32");
+        Check(r.text.contains("std::uint64_t c = 3;"), "unsigned long long -> uint64");
+        Check(r.text.contains("std::uint64_t d = 4;"), "long unsigned int (reordered) -> uint64");
+        Check(r.text.contains("std::uint16_t e = 5;"), "unsigned short -> uint16");
+        Check(r.text.contains("std::int32_t f = 6;"), "bare signed -> int32");
+        Check(r.text.contains("std::int8_t g = 7;"), "signed char -> int8");
+        Check(r.text.contains("static_cast<std::uint8_t>(g)"), "unsigned char -> uint8");
+        Check(r.text.contains("char text = 'x';"), "bare char stays (text, not an integer)");
+        Check(r.text.contains("long double pi = 3.14L;"), "long double stays (floating type)");
+    }
+
+    // brace-style: Allman brace joins; standalone scope block stays.
+    {
+        RuleRun r = RunRule("void Foo()\n{\n}\n\nvoid Bar() {\n    Baz();\n    {\n        Qux();\n    }\n}\n", "brace-style", LintMode::Apply);
+        Check(r.text.contains("void Foo() {"), "Allman brace joined onto header");
+        Check(r.text.contains("Baz();\n    {"), "scope block brace untouched");
+    }
+
+    // if-single-line: short body joins; braced body stays.
+    {
+        RuleRun r = RunRule("void F(bool b) {\n    if (b)\n        Run();\n    if (b) {\n        Run();\n    }\n}\n", "if-single-line", LintMode::Apply);
+        Check(r.text.contains("if (b) Run();"), "single-statement if body joined");
+        Check(r.text.contains("if (b) {"), "braced if body untouched");
+    }
+
+    // single-declaration: simple multi-decl splits; pointer decl only reports.
+    {
+        RuleRun r = RunRule("void F() {\n    bool a = false, b = true;\n}\n", "single-declaration", LintMode::Apply);
+        Check(r.text.contains("bool a = false;\n    bool b = true;"), "multi-declaration split");
+    }
+
+    // wrap-join: short wrapped call joins; operator chain joins; long stays.
+    {
+        RuleRun r = RunRule("void F() {\n    G(alpha,\n      beta);\n    bool x = alpha\n        && beta;\n}\n", "wrap-join", LintMode::Apply);
+        Check(r.text.contains("G(alpha, beta);"), "wrapped call arguments joined");
+        Check(r.text.contains("bool x = alpha && beta;"), "operator continuation joined");
+    }
+
+    // format-concat: literal-adjacent + rewrites; += RHS rewrites; args survive.
+    {
+        RuleRun r = RunRule("void F(std::string name, std::string cmd) {\n"
+                            "    std::string a = name + \".cpp\";\n"
+                            "    std::string b = \"pre-\" + name + \"-post\";\n"
+                            "    cmd += \" \" + name;\n"
+                            "    std::string keep = name + cmd;\n"
+                            "    fs::path p;\n"
+                            "    std::string c = p.stem().string() + \".pcm\";\n"
+                            "    fs::path d = std::string(cmd) + \".so\";\n"
+                            "}\n",
+                            "format-concat", LintMode::Apply);
+        Check(r.text.contains("std::string a = std::format(\"{}.cpp\", name);"), "trailing literal converts");
+        Check(!r.text.contains("namestd::format"), "replacement splices at the operand boundary");
+        Check(r.text.contains("std::string b = std::format(\"pre-{}-post\", name);"), "sandwich chain converts");
+        Check(r.text.contains("cmd += std::format(\" {}\", name);"), "+= RHS converts");
+        Check(r.text.contains("std::string keep = name + cmd;"), "literal-free + is left alone");
+        Check(r.text.contains("std::string c = std::format(\"{}.pcm\", p.stem().string());"), "call-chain left operand consumed whole (the stringstd regression)");
+        Check(r.text.contains("fs::path d = std::format(\"{}.so\", std::string(cmd));"), "constructor-call left operand consumed whole");
+    }
+    {
+        // Ternary and raw-string lines are reported, never rewritten.
+        RuleRun r = RunRule("std::string F(bool b, std::string n) { return b ? n + \".x\" : n; }\n", "format-concat", LintMode::Report);
+        Check(HasFinding(r.summary, "not auto-fixable"), "ternary concat reports instead of fixing");
+        Check(r.text.contains("n + \".x\""), "ternary concat untouched on disk");
+    }
+
+    // paren-spacing: single-space padding removed; wrapped call ends keep.
+    {
+        RuleRun r = RunRule("void F() {\n    G( x );\n}\n", "paren-spacing", LintMode::Apply);
+        Check(r.text.contains("G(x);"), "paren padding removed");
+    }
+
+    // naming: wrong-case function/type/static/global flagged; camel local passes.
+    {
+        RuleRun r = RunRule("namespace {\n"
+                            "    std::int32_t bad_global = 0;\n"
+                            "    struct lint_thing {};\n"
+                            "}\n"
+                            "void lower_func() {\n"
+                            "    static bool lowerStatic = false;\n"
+                            "    std::int32_t fineLocal = 1;\n"
+                            "}\n",
+                            "naming", LintMode::Report);
+        Check(HasFinding(r.summary, "'bad_global' should be PascalCase"), "lowercase global flagged");
+        Check(HasFinding(r.summary, "'lint_thing' should be PascalCase"), "lowercase type flagged");
+        Check(HasFinding(r.summary, "'lower_func' should be PascalCase"), "lowercase function flagged");
+        Check(HasFinding(r.summary, "'lowerStatic' should be PascalCase"), "camel static flagged");
+        Check(!HasFinding(r.summary, "fineLocal"), "camelCase local passes");
+    }
+    {
+        // Statement calls with inline lambda arguments are NOT function
+        // definitions (the any_of regression); a genuine lowercase one-liner
+        // method still is.
+        RuleRun r = RunRule("struct Holder {\n"
+                            "    bool clean() const { return true; }\n"
+                            "};\n"
+                            "void T(std::vector<std::int32_t>& v) {\n"
+                            "    bool x = std::any_of(v.begin(), v.end(), [](std::int32_t n) { return n > 0; });\n"
+                            "    std::erase_if(v, [](std::int32_t n) { return n < 0; });\n"
+                            "}\n",
+                            "naming", LintMode::Report);
+        Check(!HasFinding(r.summary, "any_of"), "call with lambda argument is not a function definition");
+        Check(!HasFinding(r.summary, "erase_if"), "bare statement call is not a function definition");
+        Check(HasFinding(r.summary, "'clean' should be PascalCase"), "lowercase one-liner method still flagged");
+    }
+
+    // enum-class + no-iostream-print reports.
+    {
+        RuleRun r = RunRule("enum Color { Red };\n", "enum-class", LintMode::Report);
+        Check(HasFinding(r.summary, "enum class"), "plain enum flagged");
+    }
+    {
+        RuleRun r = RunRule("void F() { std::cout << 1; }\n", "no-iostream-print", LintMode::Report);
+        Check(HasFinding(r.summary, "std::println"), "std::cout flagged");
+    }
+
+    // The whole ruleset is idempotent: a second Apply changes nothing.
+    {
+        std::string_view source = "int Foo()\n{\n    std::string s = std::string(\"a\") + \"b\";\n    if (true)\n        return 1;\n    return 0;\n}\n";
+        static constexpr std::string_view AllRules = "*";
+        RuleRun first = RunRule(source, AllRules, LintMode::Apply);
+        RuleRun second = RunRule(first.text, AllRules, LintMode::Apply);
+        Check(second.summary.changedFiles.empty(), "second apply of the full ruleset is a no-op");
+        Check(first.text != source, "first apply actually changed the fixture");
+    }
+
+    // Suppression directives against house transforms: the driver reverts
+    // line-preserving edits (fixed-width) and the count-changing rules check
+    // Suppressed() themselves (wrap-join).
+    {
+        RuleRun r = RunRule("void F() {\n"
+                            "    // lint-disable-next-line fixed-width-types\n"
+                            "    int keep = 1;\n"
+                            "    int convert = 2;\n"
+                            "}\n",
+                            "fixed-width-types", LintMode::Apply);
+        Check(r.text.contains("int keep = 1;"), "next-line directive keeps the suppressed int");
+        Check(r.text.contains("std::int32_t convert = 2;"), "unsuppressed line still converts");
+    }
+    {
+        RuleRun r = RunRule("void F() {\n"
+                            "    // lint-disable-next-line wrap-join\n"
+                            "    G(alpha,\n"
+                            "      beta);\n"
+                            "    H(alpha,\n"
+                            "      beta);\n"
+                            "}\n",
+                            "wrap-join", LintMode::Apply);
+        Check(r.text.contains("G(alpha,\n"), "suppressed wrap stays wrapped");
+        Check(r.text.contains("H(alpha, beta);"), "unsuppressed wrap still joins");
+    }
+
+    // wrap-join converges in ONE run: joining the inner paren wrap balances
+    // the && line, which only then becomes an operator-joinable continuation.
+    {
+        RuleRun r = RunRule("void F() {\n"
+                            "    bool ok = alpha\n"
+                            "        && beta(gamma,\n"
+                            "                delta);\n"
+                            "}\n",
+                            "wrap-join", LintMode::Apply);
+        Check(r.text.contains("bool ok = alpha && beta(gamma, delta);"), "self-enabling joins reach the fixpoint in one apply");
+        RuleRun second = RunRule(r.text, "wrap-join", LintMode::Apply);
+        Check(second.summary.changedFiles.empty(), "wrap-join is idempotent after the fixpoint");
+    }
+
+    if (Failures > 0) {
+        std::println(std::cerr, "{} assertions failed", Failures);
+        return 1;
+    }
+    return 0;
+}

tests/Lint/fixture/clean.cpp

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+
+// Fixture with no lint violations — rules asserting on dirty.cpp must not
+// fire here.
+int CleanAnswer() {
+    return 42;
+}

tests/Lint/fixture/dirty.cpp

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+
+// Fixture with deliberate violations at fixed line numbers —
+// tests/Lint/main.cpp asserts on these exact lines. Do not reflow.
+
+// MARKER inside a comment: must be invisible to CommentStripped() (line 7)
+int DirtyTab() {
+	return 1; // deliberate tab indent (line 9)
+}
+
+const char* dirtyString = "MARKER inside a string literal (line 12)";
+int MARKER_in_code = 13; // identifier survives CommentStripped() (line 13)

tests/Lint/main.cpp

@@ -0,0 +1,435 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+
+import std;
+import Crafter.Build;
+namespace fs = std::filesystem;
+using namespace Crafter;
+
+namespace {
+    std::int32_t Failures = 0;
+
+    void Check(bool cond, std::string_view msg) {
+        if (!cond) {
+            std::println(std::cerr, "FAIL: {}", msg);
+            ++Failures;
+        }
+    }
+
+    // Scratch-dir fixture for transform tests: Apply mode rewrites files, so
+    // these cases must never point at the checked-in fixture/. Each case
+    // writes its own sources into a fresh temp dir.
+    struct Scratch {
+        fs::path dir;
+        explicit Scratch(std::string_view name) {
+            dir = fs::temp_directory_path() / "crafter-build-lint-format" / name;
+            fs::remove_all(dir);
+            fs::create_directories(dir);
+        }
+        void Write(std::string_view stem, std::string_view content) const {
+            std::ofstream f(dir / std::format("{}.cpp", stem), std::ios::binary | std::ios::trunc);
+            f.write(content.data(), static_cast<std::streamsize>(content.size()));
+        }
+        std::string Read(std::string_view stem) const {
+            std::ifstream f(dir / std::format("{}.cpp", stem), std::ios::binary);
+            std::stringstream buffer;
+            buffer << f.rdbuf();
+            return std::move(buffer).str();
+        }
+        Configuration Config(std::vector<fs::path> impls) const {
+            Configuration cfg;
+            cfg.path = dir;
+            cfg.name = "fmt-fixture";
+            cfg.outputName = "fmt-fixture";
+            cfg.target = HostTarget();
+            std::array<fs::path, 0> ifaces = {};
+            cfg.GetInterfacesAndImplementations(ifaces, impls);
+            return cfg;
+        }
+    };
+
+    void AddTrimRule(Configuration& cfg) {
+        cfg.AddLintRule("trim", [](LintContext& ctx) {
+            std::string out;
+            out.reserve(ctx.content.size());
+            for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {
+                std::string_view line = ctx.Line(n);
+                bool crlf = line.ends_with('\r');
+                if (crlf) line.remove_suffix(1);
+                while (line.ends_with(' ') || line.ends_with('\t')) line.remove_suffix(1);
+                out += line;
+                if (crlf) out += '\r';
+                if (n < ctx.lines.size() || ctx.content.ends_with('\n')) out += '\n';
+            }
+            ctx.SetContent(std::move(out));
+        });
+    }
+
+    RunLintOptions Mode(LintMode m) {
+        RunLintOptions opts;
+        opts.mode = m;
+        return opts;
+    }
+
+    // Fresh Configuration over the two fixture sources. Rebuilt per case so
+    // rule registrations don't leak between them.
+    Configuration FixtureConfig() {
+        Configuration cfg;
+        cfg.path = fs::current_path() / "tests" / "Lint" / "fixture";
+        cfg.name = "lint-fixture";
+        cfg.outputName = "lint-fixture";
+        cfg.target = HostTarget();
+        std::array<fs::path, 0> ifaces = {};
+        std::array<fs::path, 2> impls = { "clean", "dirty" };
+        cfg.GetInterfacesAndImplementations(ifaces, impls);
+        return cfg;
+    }
+
+    void AddTabRule(Configuration& cfg) {
+        cfg.AddLintRule("tab-rule", [](LintContext& ctx) {
+            for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {
+                if (ctx.Line(n).contains('\t')) ctx.Report(n, "tab character");
+            }
+        });
+    }
+}
+
+// In-process tests for RunLint: rule registration, file collection over a
+// Configuration, glob filtering, --list, comment stripping, and dedup. Lint
+// only reads sources, so no Build() is needed.
+int main() {
+    // No rules registered → noRulesDefined, not Clean.
+    {
+        Configuration cfg = FixtureConfig();
+        LintSummary s = RunLint(cfg, {});
+        Check(s.noRulesDefined, "no rules -> noRulesDefined");
+        Check(!s.Clean(), "no rules -> not Clean (exit 1)");
+        Check(s.findings.empty(), "no rules -> no findings");
+    }
+
+    // tab-rule fires on dirty.cpp line 9 only; never-fires stays silent.
+    {
+        Configuration cfg = FixtureConfig();
+        AddTabRule(cfg);
+        cfg.AddLintRule("never-fires", [](LintContext&) {});
+        LintSummary s = RunLint(cfg, {});
+        Check(s.rulesRun == 2, "both rules run");
+        Check(s.filesLinted == 2, "both fixture files linted");
+        Check(s.findings.size() == 1, "exactly one finding");
+        Check(!s.Clean(), "findings -> not Clean");
+        if (!s.findings.empty()) {
+            Check(s.findings[0].file.filename() == "dirty.cpp", "finding is in dirty.cpp");
+            Check(s.findings[0].line == 9, "tab reported at line 9");
+            Check(s.findings[0].rule == "tab-rule", "finding attributed to tab-rule");
+        }
+    }
+
+    // Glob filter drops tab-rule → clean run.
+    {
+        Configuration cfg = FixtureConfig();
+        AddTabRule(cfg);
+        cfg.AddLintRule("never-fires", [](LintContext&) {});
+        RunLintOptions opts;
+        opts.globs = { "never-*" };
+        LintSummary s = RunLint(cfg, opts);
+        Check(s.rulesRun == 1, "glob filters to one rule");
+        Check(s.findings.empty(), "filtered run has no findings");
+        Check(s.Clean(), "filtered run is Clean");
+    }
+
+    // listOnly enumerates without running any rule.
+    {
+        Configuration cfg = FixtureConfig();
+        AddTabRule(cfg);
+        RunLintOptions opts;
+        opts.listOnly = true;
+        LintSummary s = RunLint(cfg, opts);
+        Check(s.findings.empty(), "listOnly records no findings");
+        Check(s.filesLinted == 0, "listOnly reads no files");
+        Check(s.rulesRun == 1, "listOnly still counts matching rules");
+    }
+
+    // CommentStripped: MARKER in a comment (line 7) and in a string literal
+    // (line 12) are blanked; the identifier at line 13 survives, and line
+    // numbers computed from the stripped text match the real file.
+    {
+        Configuration cfg = FixtureConfig();
+        cfg.AddLintRule("marker", [](LintContext& ctx) {
+            const std::string& code = ctx.CommentStripped();
+            for (std::size_t pos = code.find("MARKER"); pos != std::string::npos;
+                 pos = code.find("MARKER", pos + 1)) {
+                std::size_t line = 1 + std::count(code.begin(), code.begin() + pos, '\n');
+                ctx.Report(line, "MARKER in code");
+            }
+        });
+        LintSummary s = RunLint(cfg, {});
+        Check(s.findings.size() == 1, "only the code MARKER is found");
+        if (!s.findings.empty()) {
+            Check(s.findings[0].line == 13, "code MARKER reported at line 13");
+            Check(s.findings[0].file.filename() == "dirty.cpp", "MARKER finding is in dirty.cpp");
+        }
+    }
+
+    // Duplicate rule name: first registration wins, second never runs.
+    {
+        Configuration cfg = FixtureConfig();
+        AddTabRule(cfg);
+        cfg.AddLintRule("tab-rule", [](LintContext& ctx) {
+            ctx.Report(1, "duplicate ran");
+        });
+        LintSummary s = RunLint(cfg, {});
+        Check(s.rulesRun == 1, "duplicate name deduplicated");
+        Check(s.findings.size() == 1 && s.findings[0].line == 9, "only the first registration ran");
+    }
+
+    // A throwing rule surfaces as a finding, not an unwind.
+    {
+        Configuration cfg = FixtureConfig();
+        cfg.AddLintRule("throws", [](LintContext& ctx) {
+            if (ctx.file.filename() == "clean.cpp") throw std::runtime_error("boom");
+        });
+        LintSummary s = RunLint(cfg, {});
+        Check(s.findings.size() == 1, "exception becomes a finding");
+        if (!s.findings.empty()) {
+            Check(s.findings[0].message.contains("boom"), "finding carries the exception message");
+            Check(s.findings[0].line == 0, "exception finding is whole-file (line 0)");
+        }
+    }
+
+    // --- Transform (format) cases: scratch dir, never the checked-in fixture ---
+
+    // Report mode: transform diffs become would-reformat findings; disk untouched.
+    {
+        Scratch s("report");
+        s.Write("a", "hello \nworld\n");
+        Configuration cfg = s.Config({"a"});
+        AddTrimRule(cfg);
+        LintSummary sum = RunLint(cfg, Mode(LintMode::Report));
+        Check(sum.findings.size() == 1, "one would-reformat finding");
+        if (!sum.findings.empty()) {
+            Check(sum.findings[0].line == 1, "would-reformat at line 1");
+            Check(sum.findings[0].rule == "trim", "attributed to the transform rule");
+            Check(sum.findings[0].message == "would reformat", "derived message");
+        }
+        Check(sum.changedFiles.size() == 1, "changedFiles populated in Report mode");
+        Check(!sum.Clean(), "would-reformat gates lint");
+        Check(s.Read("a") == "hello \nworld\n", "Report mode never writes");
+    }
+
+    // Apply mode: disk rewritten; a sibling report-only rule's findings are
+    // still recorded (the verb, not the driver, ignores them).
+    {
+        Scratch s("apply");
+        s.Write("a", "hello \nworld\n");
+        Configuration cfg = s.Config({"a"});
+        AddTrimRule(cfg);
+        cfg.AddLintRule("note", [](LintContext& ctx) { ctx.Report(2, "note"); });
+        LintSummary sum = RunLint(cfg, Mode(LintMode::Apply));
+        Check(s.Read("a") == "hello\nworld\n", "Apply rewrites the file");
+        Check(sum.changedFiles.size() == 1, "one file formatted");
+        bool hasNote = std::any_of(sum.findings.begin(), sum.findings.end(), [](const LintFinding& f) { return f.rule == "note"; });
+        Check(hasNote, "report-only findings still recorded in Apply mode");
+        Check(sum.errors == 0, "clean apply has no errors");
+    }
+
+    // Check mode: reported, not written.
+    {
+        Scratch s("check");
+        s.Write("a", "hello \n");
+        Configuration cfg = s.Config({"a"});
+        AddTrimRule(cfg);
+        LintSummary sum = RunLint(cfg, Mode(LintMode::Check));
+        Check(sum.changedFiles.size() == 1, "Check records would-change file");
+        Check(!sum.findings.empty(), "Check records would-reformat findings");
+        Check(s.Read("a") == "hello \n", "Check mode never writes");
+    }
+
+    // Chaining: rule2 sees rule1's output; both attributed in Report mode.
+    {
+        Scratch s("chain");
+        s.Write("a", "AAA\n");
+        Configuration cfg = s.Config({"a"});
+        cfg.AddLintRule("one", [](LintContext& ctx) {
+            std::string c = ctx.content;
+            if (auto p = c.find("AAA"); p != std::string::npos) c.replace(p, 3, "BBB");
+            ctx.SetContent(std::move(c));
+        });
+        cfg.AddLintRule("two", [](LintContext& ctx) {
+            std::string c = ctx.content;
+            if (auto p = c.find("BBB"); p != std::string::npos) c.replace(p, 3, "CCC");
+            ctx.SetContent(std::move(c));
+        });
+        LintSummary rep = RunLint(cfg, Mode(LintMode::Report));
+        bool one = std::any_of(rep.findings.begin(), rep.findings.end(), [](const LintFinding& f) { return f.rule == "one"; });
+        bool two = std::any_of(rep.findings.begin(), rep.findings.end(), [](const LintFinding& f) { return f.rule == "two"; });
+        Check(one && two, "chained transforms both attributed");
+        Check(s.Read("a") == "AAA\n", "Report leaves chain input untouched");
+        LintSummary app = RunLint(cfg, Mode(LintMode::Apply));
+        Check(s.Read("a") == "CCC\n", "Apply composes chained transforms");
+        Check(app.changedFiles.size() == 1, "chain counts as one changed file");
+    }
+
+    // A throwing transform is reverted — half-applied content never lands.
+    {
+        Scratch s("throws");
+        s.Write("a", "keep\n");
+        Configuration cfg = s.Config({"a"});
+        cfg.AddLintRule("bad", [](LintContext& ctx) {
+            ctx.SetContent("garbage");
+            throw std::runtime_error("mid-transform");
+        });
+        LintSummary sum = RunLint(cfg, Mode(LintMode::Apply));
+        Check(s.Read("a") == "keep\n", "throwing transform reverted, disk untouched");
+        Check(sum.errors == 1, "exception counted as error");
+        Check(sum.changedFiles.empty(), "reverted transform is not a change");
+        bool threw = std::any_of(sum.findings.begin(), sum.findings.end(),
+                                 [](const LintFinding& f) {
+                                     return f.line == 0 && f.message.contains("mid-transform");
+                                 });
+        Check(threw, "exception surfaced as line-0 finding");
+    }
+
+    // CRLF byte fidelity + the final-newline whole-file (line 0) diff edge.
+    {
+        Scratch s("bytes");
+        s.Write("crlf", "x \r\ny\r\n");
+        s.Write("noeol", "a\nb");
+        Configuration cfg = s.Config({"crlf", "noeol"});
+        AddTrimRule(cfg);
+        cfg.AddLintRule("final-newline", [](LintContext& ctx) {
+            if (!ctx.content.empty() && !ctx.content.ends_with('\n')) {
+                ctx.SetContent(ctx.content + '\n');
+            }
+        });
+        LintSummary rep = RunLint(cfg, Mode(LintMode::Report));
+        bool wholeFile = std::any_of(rep.findings.begin(), rep.findings.end(),
+                                     [](const LintFinding& f) {
+                                         return f.rule == "final-newline" && f.line == 0;
+                                     });
+        Check(wholeFile, "missing final newline reports as whole-file finding");
+        RunLint(cfg, Mode(LintMode::Apply));
+        Check(s.Read("crlf") == "x\r\ny\r\n", "trim preserves CRLF endings");
+        Check(s.Read("noeol") == "a\nb\n", "final-newline appends exactly one newline");
+    }
+
+    // Mixed rule: Report() and SetContent() from the same rule.
+    {
+        Scratch s("mixed");
+        s.Write("a", "bad \n");
+        Configuration cfg = s.Config({"a"});
+        cfg.AddLintRule("mixed", [](LintContext& ctx) {
+            ctx.Report(1, "flagged");
+            std::string c = ctx.content;
+            if (auto p = c.find(' '); p != std::string::npos) c.erase(p, 1);
+            ctx.SetContent(std::move(c));
+        });
+        LintSummary rep = RunLint(cfg, Mode(LintMode::Report));
+        bool flagged = std::any_of(rep.findings.begin(), rep.findings.end(), [](const LintFinding& f) { return f.message == "flagged"; });
+        bool reformat = std::any_of(rep.findings.begin(), rep.findings.end(), [](const LintFinding& f) { return f.message == "would reformat"; });
+        Check(flagged && reformat, "mixed rule records both finding kinds");
+        RunLint(cfg, Mode(LintMode::Apply));
+        Check(s.Read("a") == "bad\n", "mixed rule's transform applied");
+    }
+
+    // Idempotency: a second Apply is a no-op; identical SetContent bytes are
+    // not a change (compare-by-value, not call-tracking).
+    {
+        Scratch s("idempotent");
+        s.Write("a", "hello \n");
+        Configuration cfg = s.Config({"a"});
+        AddTrimRule(cfg);
+        LintSummary first = RunLint(cfg, Mode(LintMode::Apply));
+        Check(first.changedFiles.size() == 1, "first apply changes the file");
+        LintSummary second = RunLint(cfg, Mode(LintMode::Apply));
+        Check(second.changedFiles.empty(), "second apply is a no-op");
+        Check(second.findings.empty(), "no-op apply has no findings");
+    }
+
+    // --- Suppression directives (engine-level) ---
+
+    // next-line directive with a rule name suppresses that finding only.
+    {
+        Scratch s("suppress-next-line");
+        s.Write("a", "// lint-disable-next-line flag\nbad\nbad\n");
+        Configuration cfg = s.Config({"a"});
+        cfg.AddLintRule("flag", [](LintContext& ctx) {
+            for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {
+                if (ctx.Line(n).contains("bad")) ctx.Report(n, "bad");
+            }
+        });
+        LintSummary sum = RunLint(cfg, Mode(LintMode::Report));
+        Check(sum.findings.size() == 1, "next-line directive suppresses one finding");
+        if (!sum.findings.empty()) Check(sum.findings[0].line == 3, "the unsuppressed line still reports");
+    }
+
+    // next-line suppression also reverts a transform's edit on that line —
+    // `format` must not rewrite what lint is told to ignore.
+    {
+        Scratch s("suppress-transform");
+        s.Write("a", "// lint-disable-next-line trim\nkeep \ntrim \n");
+        Configuration cfg = s.Config({"a"});
+        AddTrimRule(cfg);
+        RunLint(cfg, Mode(LintMode::Apply));
+        Check(s.Read("a") == "// lint-disable-next-line trim\nkeep \ntrim\n",
+              "suppressed line keeps its bytes; the unsuppressed one is fixed");
+    }
+
+    // Multiple rule names on one directive (space- or comma-separated).
+    {
+        Scratch s("suppress-multi");
+        s.Write("a", "// lint-disable-next-line flagA, flagB\nbad \nbad \n");
+        Configuration cfg = s.Config({"a"});
+        cfg.AddLintRule("flagA", [](LintContext& ctx) {
+            for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {
+                if (ctx.Line(n).contains("bad")) ctx.Report(n, "A");
+            }
+        });
+        cfg.AddLintRule("flagB", [](LintContext& ctx) {
+            for (std::size_t n = 1; n <= ctx.lines.size(); ++n) {
+                if (ctx.Line(n).contains("bad")) ctx.Report(n, "B");
+            }
+        });
+        AddTrimRule(cfg);
+        LintSummary sum = RunLint(cfg, Mode(LintMode::Report));
+        bool line2Silent = std::none_of(sum.findings.begin(), sum.findings.end(), [](const LintFinding& f) { return f.line == 2 && f.rule != "trim"; });
+        bool line3Loud = std::count_if(sum.findings.begin(), sum.findings.end(), [](const LintFinding& f) { return f.line == 3; }) >= 2;
+        Check(line2Silent, "both named rules suppressed on the target line");
+        bool trimStillFires = std::any_of(sum.findings.begin(), sum.findings.end(), [](const LintFinding& f) { return f.line == 2 && f.rule == "trim"; });
+        Check(trimStillFires, "unnamed rule still fires on the target line");
+        Check(line3Loud, "unsuppressed line reports from both rules");
+    }
+
+    // file-level all-rules directive silences findings and stops format.
+    {
+        Scratch s("suppress-file");
+        s.Write("a", "// lint-disable-file\nbad \n");
+        Configuration cfg = s.Config({"a"});
+        AddTrimRule(cfg);
+        cfg.AddLintRule("flag", [](LintContext& ctx) { ctx.Report(2, "bad"); });
+        LintSummary rep = RunLint(cfg, Mode(LintMode::Report));
+        Check(rep.findings.empty(), "file-level all directive suppresses every finding");
+        LintSummary app = RunLint(cfg, Mode(LintMode::Apply));
+        Check(app.changedFiles.empty(), "file-level all directive stops format");
+        Check(s.Read("a") == "// lint-disable-file\nbad \n", "file bytes untouched");
+    }
+
+    // file-level with a rule name: that rule is dead, others still act.
+    {
+        Scratch s("suppress-file-rule");
+        s.Write("a", "// lint-disable-file flag\nbad \n");
+        Configuration cfg = s.Config({"a"});
+        AddTrimRule(cfg);
+        cfg.AddLintRule("flag", [](LintContext& ctx) { ctx.Report(2, "bad"); });
+        LintSummary rep = RunLint(cfg, Mode(LintMode::Report));
+        bool onlyTrim = !rep.findings.empty() && std::all_of(rep.findings.begin(), rep.findings.end(), [](const LintFinding& f) { return f.rule == "trim"; });
+        Check(onlyTrim, "file-level rule directive kills that rule, trim still fires");
+        RunLint(cfg, Mode(LintMode::Apply));
+        Check(s.Read("a") == "// lint-disable-file flag\nbad\n", "other rules still format");
+    }
+
+    if (Failures > 0) {
+        std::println(std::cerr, "{} assertions failed", Failures);
+        return 1;
+    }
+    return 0;
+}

tests/ModuleInterface/fixture/Greeter.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 export module Greeter;
 import std;

tests/ModuleInterface/fixture/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Greeter;

tests/ModuleInterface/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
@@ -28,15 +28,11 @@ int main() {
         return 1;
     }
     if (cfg.implementations[0].moduleDependencies.size() != 1) {
-        std::println(std::cerr,
+        std::println(std::cerr, "expected main.cpp to depend on 1 module, got {}", cfg.implementations[0].moduleDependencies.size());
-            "expected main.cpp to depend on 1 module, got {}",
-            cfg.implementations[0].moduleDependencies.size());
         return 1;
     }
     if (cfg.implementations[0].moduleDependencies[0]->name != "Greeter") {
-        std::println(std::cerr,
+        std::println(std::cerr, "expected dep 'Greeter', got '{}'", cfg.implementations[0].moduleDependencies[0]->name);
-            "expected dep 'Greeter', got '{}'",
-            cfg.implementations[0].moduleDependencies[0]->name);
         return 1;
     }
 
@@ -56,8 +52,7 @@ int main() {
 
     auto run = RunCommandWithTimeout(bin.string(), std::chrono::seconds(10));
     if (run.exitCode != 0 || run.timedOut || run.crashed) {
-        std::println(std::cerr, "binary did not exit cleanly: exit={} output={}",
+        std::println(std::cerr, "binary did not exit cleanly: exit={} output={}", run.exitCode, run.output);
-            run.exitCode, run.output);
         return 1;
     }
     if (run.output != "ok-from-module") {

tests/RunSingleTestExit/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
@@ -7,28 +7,24 @@ namespace fs = std::filesystem;
 using namespace Crafter;
 
 namespace {
-    int failures = 0;
+    std::int32_t Failures = 0;
 
     void Check(bool cond, std::string_view msg) {
         if (!cond) {
             std::println(std::cerr, "FAIL: {}", msg);
-            ++failures;
+            ++Failures;
         }
     }
 
     // Write a tiny POSIX shell script that exits with `code` and return its
     // path. The harness invokes `<binary> <args>` through the host shell, so
     // a #!/bin/sh script works as a stand-in for a real test binary.
-    fs::path WriteExitScript(const fs::path& dir, std::string_view stem, int code) {
+    fs::path WriteExitScript(const fs::path& dir, std::string_view stem, std::int32_t code) {
         fs::path script = dir / stem;
         std::ofstream out(script);
         out << "#!/bin/sh\nexit " << code << "\n";
         out.close();
-        fs::permissions(script,
+        fs::permissions(script, fs::perms::owner_read | fs::perms::owner_write | fs::perms::owner_exec | fs::perms::group_read | fs::perms::group_exec | fs::perms::others_read | fs::perms::others_exec, fs::perm_options::replace);
-            fs::perms::owner_read | fs::perms::owner_write | fs::perms::owner_exec
-            | fs::perms::group_read | fs::perms::group_exec
-            | fs::perms::others_read | fs::perms::others_exec,
-            fs::perm_options::replace);
         return script;
     }
 }
@@ -82,8 +78,8 @@ int main() {
 
     fs::remove_all(dir, ec);
 
-    if (failures > 0) {
+    if (Failures > 0) {
-        std::println(std::cerr, "{} assertions failed", failures);
+        std::println(std::cerr, "{} assertions failed", Failures);
         return 1;
     }
     return 0;

tests/ShaderCompile/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;

tests/StandardArgs/main.cpp

@@ -1,17 +1,17 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
 using namespace Crafter;
 
 namespace {
-    int failures = 0;
+    std::int32_t Failures = 0;
 
     void Check(bool cond, std::string_view msg) {
         if (!cond) {
             std::println(std::cerr, "FAIL: {}", msg);
-            ++failures;
+            ++Failures;
         }
     }
 }
@@ -83,8 +83,8 @@ int main() {
         Check(!q.Get("--other=").has_value(), "ArgQuery::Get returns nullopt for absent prefix");
     }
 
-    if (failures > 0) {
+    if (Failures > 0) {
-        std::println(std::cerr, "{} assertions failed", failures);
+        std::println(std::cerr, "{} assertions failed", Failures);
         return 1;
     }
     return 0;

tests/StaticLib/fixture/Greet.cppm

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 export module Greet;
 import std;

tests/StaticLib/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;

tests/TestRunnerSpec/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
@@ -13,12 +13,12 @@ extern "C" int setenv(const char* name, const char* value, int overwrite);
 extern "C" int unsetenv(const char* name);
 
 namespace {
-    int failures = 0;
+    std::int32_t Failures = 0;
 
     void Check(bool cond, std::string_view msg) {
         if (!cond) {
             std::println(std::cerr, "FAIL: {}", msg);
-            ++failures;
+            ++Failures;
         }
     }
 }
@@ -84,8 +84,7 @@ int main() {
         cfg.target = "aarch64-linux-gnu";
         cfg.sysroot = "/opt/alarm-sysroot";
         TestRunner r = TestRunner::ForTarget(cfg);
-        Check(r.exec.find("QEMU_LD_PREFIX=/opt/alarm-sysroot") != std::string::npos,
+        Check(r.exec.find("QEMU_LD_PREFIX=/opt/alarm-sysroot") != std::string::npos, "ForTarget propagates sysroot to QEMU_LD_PREFIX");
-            "ForTarget propagates sysroot to QEMU_LD_PREFIX");
     }
     {
         // From a Linux host the only sensible way to run x86_64-w64-mingw32 is wine.
@@ -101,17 +100,17 @@ int main() {
     {
         // Use a unique fake triple so we don't stomp on a real env var the
         // CI/dev shell may have set.
-        const char* name = "CRAFTER_BUILD_RUNNER_fake_target_for_unit_test";
+        const std::string name = "CRAFTER_BUILD_RUNNER_fake_target_for_unit_test";
-        setenv(name, "cmd:fake-tool", 1);
+        setenv(name.c_str(), "cmd:fake-tool", 1);
         TestRunner r = TestRunner::FromEnv("fake-target-for-unit-test", TestRunner::Local());
         Check(r.name == "cmd:fake-tool", "FromEnv reads CRAFTER_BUILD_RUNNER_<target>");
-        unsetenv(name);
+        unsetenv(name.c_str());
         TestRunner fallback = TestRunner::FromEnv("fake-target-for-unit-test", TestRunner::Local());
         Check(fallback.IsLocal(), "FromEnv falls back when env var is unset");
     }
 
-    if (failures > 0) {
+    if (Failures > 0) {
-        std::println(std::cerr, "{} assertions failed", failures);
+        std::println(std::cerr, "{} assertions failed", Failures);
         return 1;
     }
     return 0;

tests/VariantId/main.cpp

@@ -1,17 +1,17 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
 using namespace Crafter;
 
 namespace {
-    int failures = 0;
+    std::int32_t Failures = 0;
 
     void Check(bool cond, std::string_view msg) {
         if (!cond) {
             std::println(std::cerr, "FAIL: {}", msg);
-            ++failures;
+            ++Failures;
         }
     }
 
@@ -115,8 +115,8 @@ int main() {
         Check(a.BinDir() != b.BinDir(), "different VariantId yields different BinDir");
     }
 
-    if (failures > 0) {
+    if (Failures > 0) {
-        std::println(std::cerr, "{} assertions failed", failures);
+        std::println(std::cerr, "{} assertions failed", Failures);
         return 1;
     }
     return 0;

tests/WasiBrowserRuntime/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
@@ -41,9 +41,7 @@ int main() {
     } else if (fs::exists(systemHome / "wasi-runtime" / "runtime.js")) {
         setenv("CRAFTER_BUILD_HOME", systemHome.c_str(), 1);
     } else {
-        std::println(std::cerr,
+        std::println(std::cerr, "wasi-runtime assets not found near {} or {}", repoWasi.string(), systemHome.string());
-            "wasi-runtime assets not found near {} or {}",
-            repoWasi.string(), systemHome.string());
         return 77;  // skipped — environmental, not a code defect
     }
 

tests/WasmVariants/main.cpp

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 import std;
 import Crafter.Build;
@@ -15,9 +15,9 @@ extern "C" int setenv(const char* name, const char* value, int overwrite);
 // actual multi-.wasm production is exercised by a real wasm build (manual /
 // integration), not here — same boundary the WasiBrowserRuntime test draws.
 namespace {
-    int failures = 0;
+    std::int32_t Failures = 0;
     void Check(bool cond, std::string_view msg) {
-        if (!cond) { std::println(std::cerr, "FAIL: {}", msg); ++failures; }
+        if (!cond) { std::println(std::cerr, "FAIL: {}", msg); ++Failures; }
     }
 }
 
@@ -68,7 +68,7 @@ int main() {
             setenv("CRAFTER_BUILD_HOME", systemHome.c_str(), 1);
         } else {
             std::println(std::cerr, "wasi-runtime assets not found; skipping manifest check");
-            return failures ? 1 : 77;
+            return Failures ? 1 : 77;
         }
 
         Configuration cfg;
@@ -103,15 +103,14 @@ int main() {
             // prefers it when probes pass.
             auto relaxedPos = j.find("relaxed-simd");
             auto baselinePos = j.find("\"wvhelper.wasm\"");
-            Check(relaxedPos != std::string::npos && baselinePos != std::string::npos && relaxedPos < baselinePos,
+            Check(relaxedPos != std::string::npos && baselinePos != std::string::npos && relaxedPos < baselinePos, "relaxed-simd entry precedes baseline");
-                  "relaxed-simd entry precedes baseline");
         }
 
         fs::remove_all(cfg.path, ec);
     }
 
-    if (failures > 0) {
+    if (Failures > 0) {
-        std::println(std::cerr, "{} assertions failed", failures);
+        std::println(std::cerr, "{} assertions failed", Failures);
         return 1;
     }
     return 0;

wasi-runtime/runtime.js

@@ -1,5 +1,5 @@
-//SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-License-Identifier: LGPL-3.0-only
-//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
 // Minimal browser WASI shim. Loaded by index.html, which sets
 // window.CRAFTER_WASM_URL before this script runs so a single runtime.js