Crafter.Build/tests/Lint/main.cpp

// 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);
                const 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");
        const 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));
        const bool one = std::any_of(rep.findings.begin(), rep.findings.end(), [](const LintFinding& f) { return f.rule == "one"; });
        const 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");
        const 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));
        const 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));
        const bool flagged = std::any_of(rep.findings.begin(), rep.findings.end(), [](const LintFinding& f) { return f.message == "flagged"; });
        const 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));
        const bool line2Silent = std::none_of(sum.findings.begin(), sum.findings.end(), [](const LintFinding& f) { return f.line == 2 && f.rule != "trim"; });
        const 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");
        const 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));
        const 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");
    }

    // ---------------- token layer ----------------
    //
    // The source is spelled with escaped literals rather than a raw string so
    // that this file stays lintable by the very rules under test; the scratch
    // file it writes does contain a genuine multi-line raw string.
    {
        constexpr std::string_view Source =
            "#ifdef CRAFTER_LINT_NEVER_DEFINED\n"   // 1
            "void HiddenBranch();\n"                // 2
            "#endif\n"                              // 3
            "// a real comment\n"                   // 4
            "int url = 1; // https://example.com\n" // 5
            "auto raw = R\"raw(spans lines\n"       // 6
            "  // not a comment\n"                  // 7
            "  int notADecl;\n"                     // 8
            ")raw\";\n";                            // 9

        Scratch s("tokens");
        s.Write("f", Source);
        Configuration cfg = s.Config({"f"});
        cfg.AddLintRule("tokens", [](LintContext& ctx) {
            std::span<const LintToken> toks = ctx.Tokens();
            Check(!toks.empty(), "tokens: file lexes to a non-empty stream");

            // Every token's offset/length must address its own bytes, or a
            // transform editing at an offset would corrupt the file.
            bool offsetsSound = true;
            for (const LintToken& t : toks) {
                if (t.offset + t.length > ctx.content.size() || ctx.TokenText(t).empty()) offsetsSound = false;
            }
            Check(offsetsSound, "tokens: every offset/length addresses real bytes");

            // Ordered by offset, so binary search in TokensOnLine is valid.
            const bool ordered = std::ranges::is_sorted(toks, {}, &LintToken::offset);
            Check(ordered, "tokens: stream is in source order");

            // Inactive #ifdef branch is still lexed — this is what keeps token
            // rules covering every platform, unlike an AST.
            const bool sawHidden = std::ranges::any_of(toks, [&](const LintToken& t) {
                return t.kind == LintTokenKind::Identifier && ctx.TokenText(t) == "HiddenBranch";
            });
            Check(sawHidden, "tokens: inactive #ifdef branch is lexed");

            // A multi-line raw string is exactly one Literal, comment markers
            // and declarations inside it included.
            auto isRaw = [&](const LintToken& t) { return ctx.TokenText(t).starts_with("R\"raw("); };
            Check(std::ranges::count_if(toks, isRaw) == 1, "tokens: raw string is a single token");
            auto raw = std::ranges::find_if(toks, isRaw);
            if (raw != toks.end()) {
                Check(raw->kind == LintTokenKind::Literal, "tokens: raw string is a Literal");
                Check(raw->line == 6, "tokens: raw string starts on line 6");
                Check(ctx.TokenText(*raw).contains("// not a comment"), "tokens: raw string body kept intact");
                Check(ctx.TokenText(*raw).ends_with(")raw\""), "tokens: raw string spans to its own terminator");
            }

            // The only comments are the two real ones on lines 4 and 5 — the
            // `//` on line 7 lives inside the raw string.
            std::vector<std::size_t> commentLines;
            for (const LintToken& t : toks) {
                if (t.kind == LintTokenKind::Comment) commentLines.push_back(t.line);
            }
            Check(commentLines == std::vector<std::size_t>{4, 5}, "tokens: only real comments are Comment tokens");
            Check(ctx.LineHasComment(4), "tokens: LineHasComment finds a whole-line comment");
            Check(ctx.LineHasComment(5), "tokens: LineHasComment finds a trailing comment");
            Check(!ctx.LineHasComment(7), "tokens: `//` inside a raw string is not a comment");
            Check(!ctx.LineHasComment(2), "tokens: code-only line has no comment");

            // TokensOnLine brackets by starting line.
            std::span<const LintToken> line2 = ctx.TokensOnLine(2);
            Check(!line2.empty() && ctx.TokenText(line2.front()) == "void", "tokens: TokensOnLine starts at the line's first token");
            Check(std::ranges::all_of(line2, [](const LintToken& t) { return t.line == 2; }), "tokens: TokensOnLine stays on its line");

            // SetContent must invalidate the cache, or offsets point into a
            // buffer that no longer exists.
            ctx.SetContent("int replaced;\n");
            std::span<const LintToken> after = ctx.Tokens();
            Check(!after.empty() && ctx.TokenText(after.front()) == "int", "tokens: re-lexed after SetContent");
            Check(std::ranges::none_of(after, [&](const LintToken& t) { return ctx.TokenText(t) == "HiddenBranch"; }), "tokens: stale tokens are dropped after SetContent");
        });
        RunLint(cfg, Mode(LintMode::Report));
    }

    // CommentStripped over a raw string holding an ODD number of quotes. The
    // character-scanning version treated R"( as an ordinary string open, so the
    // quote inside the body closed it early and every following line was
    // swallowed as literal text — code after the raw string vanished from the
    // stripped view. Lexing gets the extent right.
    {
        constexpr std::string_view Source =
            "auto banner = R\"(he said \"hi)\";\n" // 1: one quote inside the body
            "int afterRaw = 2;\n"                  // 2: must survive as code
            "// MARKER comment\n"                  // 3
            "auto plain = \"MARKER text\";\n";     // 4

        Scratch s("strip-rawstring");
        s.Write("f", Source);
        Configuration cfg = s.Config({"f"});
        cfg.AddLintRule("strip", [](LintContext& ctx) {
            const std::string& code = ctx.CommentStripped();
            Check(code.size() == ctx.content.size(), "strip: byte length preserved");
            Check(std::ranges::count(code, '\n') == std::ranges::count(ctx.content, '\n'), "strip: newlines preserved");
            Check(code.contains("afterRaw"), "strip: code after an odd-quoted raw string survives");
            Check(!code.contains("he said"), "strip: raw string body is blanked");
            Check(!code.contains("MARKER"), "strip: comment and literal bodies are blanked");
            Check(code.contains("auto plain ="), "strip: code around a literal survives");
            // The raw string collapses to R"…" — exactly two quotes, so rules
            // that bracket a literal by counting quotes still work.
            std::string_view line1 = std::string_view(code).substr(0, code.find('\n'));
            Check(std::ranges::count(line1, '"') == 2, "strip: raw string leaves exactly two quotes");
        });
        RunLint(cfg, Mode(LintMode::Report));
    }

    // Non-C++ extensions are not lexed: GLSL through a C++ lexer would produce
    // plausible-looking nonsense rather than an honest refusal.
    {
        Scratch s("tokens-foreign");
        fs::path shader = s.dir / "f.frag";
        {
            std::ofstream f(shader, std::ios::binary | std::ios::trunc);
            f << "#version 450\nvoid main() { }\n";
        }
        Configuration cfg = s.Config({});
        cfg.shaders.emplace_back(fs::path(shader), "main", ShaderType::Fragment);
        cfg.AddLintRule("no-lex", [](LintContext& ctx) {
            Check(ctx.Tokens().empty(), "tokens: shaders are not lexed as C++");
        });
        RunLint(cfg, Mode(LintMode::Report));
    }

    // ---------------- AST layer ----------------
    //
    // A standalone source with no imports, so it parses without this project's
    // PCMs and the case stays a unit test.
    {
        constexpr std::string_view Source =
            "#include <string>\n"                         // 1
            "namespace Demo {\n"                          // 2
            "    enum class Scoped { A, B };\n"           // 3
            "    enum Plain { C, D };\n"                  // 4
            "    struct Widget {\n"                       // 5
            "        int count;\n"                        // 6
            "        std::string name;\n"                 // 7
            "    };\n"                                    // 8
            "    static int GlobalCounter = 0;\n"         // 9
            "    constexpr int Limit = 10;\n"             // 10
            "    int Compute(int input) {\n"              // 11
            "        int local = input;\n"                // 12
            "        return local;\n"                     // 13
            "    }\n"                                     // 14
            "}\n";                                        // 15

        Scratch s("ast");
        s.Write("f", Source);
        Configuration cfg = s.Config({"f"});
        cfg.AddAstLintRule("ast", [](LintContext& ctx) {
            Check(ctx.AstAvailable(), std::format("ast: parse succeeded ({})", ctx.AstUnavailableReason()));
            std::span<const LintDecl> decls = ctx.Decls();
            Check(!decls.empty(), "ast: declarations found");

            auto find = [&](LintDeclKind kind, std::string_view name) -> const LintDecl* {
                auto it = std::ranges::find_if(decls, [&](const LintDecl& d) { return d.kind == kind && d.name == name; });
                return it == decls.end() ? nullptr : &*it;
            };
            auto parentOf = [&](const LintDecl& d) -> const LintDecl* {
                return d.parent == LintNoParent ? nullptr : &decls[d.parent];
            };

            // Only this file's declarations: <string> drags in thousands and
            // none of them may appear here.
            Check(std::ranges::none_of(decls, [](const LintDecl& d) { return d.name == "basic_string"; }), "ast: declarations from #included headers are excluded");

            const LintDecl* demo = find(LintDeclKind::Namespace, "Demo");
            Check(demo != nullptr && demo->line == 2, "ast: namespace found at its own line");

            // The whole point for enum-class: an exact query, not a regex.
            const LintDecl* scoped = find(LintDeclKind::Enum, "Scoped");
            const LintDecl* plain = find(LintDeclKind::Enum, "Plain");
            Check(scoped != nullptr && scoped->isScopedEnum, "ast: enum class is scoped");
            Check(plain != nullptr && !plain->isScopedEnum, "ast: plain enum is not scoped");
            Check(scoped != nullptr && parentOf(*scoped) == demo, "ast: enum's parent is the namespace");

            // The whole point for naming: scope without a brace stack.
            const LintDecl* widget = find(LintDeclKind::Struct, "Widget");
            const LintDecl* count = find(LintDeclKind::Field, "count");
            Check(widget != nullptr, "ast: struct found");
            Check(count != nullptr && parentOf(*count) == widget, "ast: field's parent is its struct");
            Check(count != nullptr && count->type == "int", "ast: field carries a resolved type");
            const LintDecl* name = find(LintDeclKind::Field, "name");
            Check(name != nullptr && name->type.contains("string"), "ast: library type resolves");

            const LintDecl* global = find(LintDeclKind::Variable, "GlobalCounter");
            Check(global != nullptr && global->isStatic, "ast: static storage class reported");
            const LintDecl* limit = find(LintDeclKind::Variable, "Limit");
            Check(limit != nullptr && limit->isConstexpr, "ast: constexpr reported");
            Check(global != nullptr && !global->isConstexpr, "ast: non-constexpr not misreported");

            const LintDecl* compute = find(LintDeclKind::Function, "Compute");
            const LintDecl* local = find(LintDeclKind::Variable, "local");
            const LintDecl* input = find(LintDeclKind::Parameter, "input");
            Check(compute != nullptr && compute->isDefinition, "ast: function definition reported");
            Check(input != nullptr && parentOf(*input) == compute, "ast: parameter's parent is its function");
            // A local's parent is the function, not the namespace — which is
            // exactly the distinction the brace stack was approximating.
            Check(local != nullptr && parentOf(*local) == compute, "ast: local's parent is its function");
            Check(global != nullptr && parentOf(*global) == demo, "ast: namespace-scope variable's parent is the namespace");

            // Extents must address the declaration's own bytes so a transform
            // can mark a region untouchable.
            Check(widget != nullptr && widget->end > widget->begin && widget->end <= ctx.content.size(), "ast: extent is in range");
            if (count != nullptr) {
                Check(std::string_view(ctx.content).substr(count->begin, count->end - count->begin) == "int count", "ast: extent brackets exactly the declaration");
            }
        });
        RunLint(cfg, Mode(LintMode::Report));
    }

    // A module interface unit. libclang reports `export namespace X { … }` as a
    // childless CXCursor_UnexposedDecl and refuses to descend, so without the
    // export-blanking pass every declaration in it would be invisible — which
    // is five of this repo's own interfaces, 677 lines. Blanking the keyword is
    // byte-length preserving, so the lines reported here must match the file.
    //
    // The source lives in fixture/ExportNamespace.cppm.in rather than inline:
    // an `export module` spelled in this file's own text would be picked up by
    // the build's module scanner as a real interface of this project.
    {
        Scratch s("ast-module");
        fs::copy_file(fs::current_path() / "tests" / "Lint" / "fixture" / "ExportNamespace.cppm.in", s.dir / "Demo.cppm", fs::copy_options::overwrite_existing);
        Configuration cfg;
        cfg.path = s.dir;
        cfg.name = "ast-module";
        cfg.outputName = "ast-module";
        cfg.target = HostTarget();
        std::array<fs::path, 1> ifaces = { "Demo" };
        std::array<fs::path, 0> impls = {};
        cfg.GetInterfacesAndImplementations(ifaces, impls);
        cfg.AddAstLintRule("ast-module", [](LintContext& ctx) {
            Check(ctx.AstAvailable(), std::format("ast-module: parse succeeded ({})", ctx.AstUnavailableReason()));
            std::span<const LintDecl> decls = ctx.Decls();
            auto find = [&](LintDeclKind kind, std::string_view name) -> const LintDecl* {
                auto it = std::ranges::find_if(decls, [&](const LintDecl& d) { return d.kind == kind && d.name == name; });
                return it == decls.end() ? nullptr : &*it;
            };
            const LintDecl* ns = find(LintDeclKind::Namespace, "Demo");
            const LintDecl* mode = find(LintDeclKind::Enum, "Mode");
            const LintDecl* widget = find(LintDeclKind::Struct, "Widget");
            const LintDecl* count = find(LintDeclKind::Field, "count");
            const LintDecl* exported = find(LintDeclKind::Variable, "Exported");
            Check(ns != nullptr, "ast-module: descends into export namespace");
            Check(mode != nullptr && mode->isScopedEnum, "ast-module: enum inside export namespace is visible");
            Check(widget != nullptr && count != nullptr, "ast-module: struct and field inside export namespace are visible");
            Check(exported != nullptr, "ast-module: per-declaration export is visible");
            // Byte fidelity: blanking must not shift a single line.
            Check(ns != nullptr && ns->line == 15, "ast-module: namespace line matches the unblanked file");
            Check(mode != nullptr && mode->line == 16, "ast-module: enum line matches");
            Check(count != nullptr && count->line == 18, "ast-module: field line matches");
            Check(exported != nullptr && exported->line == 20, "ast-module: exported variable line matches");
        });
        RunLint(cfg, Mode(LintMode::Report));
    }

    // An unavailable AST must fail the run, never look like a clean file. A
    // module unit with no PCMs is the realistic way to hit this.
    {
        Scratch s("ast-unavailable");
        s.Write("f", "import Crafter.DefinitelyNotAModule;\nint Value = 1;\n");
        Configuration cfg = s.Config({"f"});
        bool ran = false;
        cfg.AddAstLintRule("needs-ast", [&ran](LintContext&) { ran = true; });
        LintSummary summary = RunLint(cfg, Mode(LintMode::Report));
        Check(!ran, "ast: rule is skipped when the AST is unavailable");
        Check(summary.errors > 0, "ast: unavailable AST counts as an error");
        Check(!summary.Clean(), "ast: unavailable AST is not Clean");
        // Explained on stderr as one grouped message rather than a finding per
        // (file, rule): a single missing PCM would otherwise bury the one fact
        // that matters. The run still failing is the part that counts, and the
        // two assertions above cover it.
    }

    // --no-ast skips those rules deliberately and exits normally.
    {
        Scratch s("ast-optout");
        s.Write("f", "import Crafter.DefinitelyNotAModule;\nint Value = 1;\n");
        Configuration cfg = s.Config({"f"});
        cfg.AddAstLintRule("needs-ast", [](LintContext& ctx) { ctx.Report(1, "should not run"); });
        RunLintOptions opts = Mode(LintMode::Report);
        opts.noAst = true;
        LintSummary summary = RunLint(cfg, opts);
        Check(summary.errors == 0, "ast: --no-ast does not error");
        Check(summary.Clean(), "ast: --no-ast run is Clean");
    }

    if (Failures > 0) {
        std::println(std::cerr, "{} assertions failed", Failures);
        return 1;
    }
    return 0;
}