Crafter.Build/lint-rules.h
Jorijn van der Graaf 649d64ae12 fix(lint): constexpr-constant asks clang's evaluator, not the initialiser tokens
The first cut scanned the initialiser's tokens and required every one to be a
literal or an operator. That is exactly the kind of approximation this work has
been removing, and it was wrong in both directions:

  const int A = sizeof(Big);   missed — `sizeof` is a keyword
  const int B = Base + 1;      missed — `Base` is an identifier
  const auto C = 5_notConstexpr;  would have been reported, wrongly

clang_Cursor_Evaluate answers the question directly. Evaluating a variable
declaration evaluates its initialiser, so anything that folds is recognised and
a call result still is not. Costs nothing measurable — lint stays at ~15s.

Found one real case the token version could not see: an EShMessages fold over
three glslang enum constants in Crafter.Build-Shader.cpp. Promoting it to
constexpr then made `naming` ask for constant naming, since a constexpr
variable is a compile-time constant — so it is `Messages` now. Two rules
agreeing on the same declaration is the intended behaviour.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-31 02:05:37 +02:00

971 lines
50 KiB
C++

// 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;
}
// clang spells a pointer type "int *"; house style attaches the star to the
// type. Only affects spelling, never which type is meant.
inline std::string NormalisePointerSpelling(std::string_view type) {
std::string out;
out.reserve(type.size());
for (char c : type) {
if ((c == '*' || c == '&') && out.ends_with(' ')) out.pop_back();
out += c;
}
return out;
}
// True for a pointer to char, as clang spells a type: "char *",
// "const char *", "char **". Deliberately not signed/unsigned char, which are
// byte buffers rather than text and were never the target.
inline bool IsCharPointer(std::string_view type) {
std::size_t star = type.find('*');
if (star == std::string_view::npos) return false;
std::string_view base = Trim(type.substr(0, star));
if (base.starts_with("const ")) base.remove_prefix(6);
if (base.starts_with("volatile ")) base.remove_prefix(9);
return base == "char";
}
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: types and functions PascalCase, variables camelCase, with
// statics, namespace-scope globals and constexpr constants PascalCase.
//
// Reads the AST. The previous version needed four std::regex, a hand-rolled
// {/} scope stack, a cumulative paren-depth counter to avoid mistaking a
// wrapped parameter list for a declaration, a keyword denylist, and a
// "function-shaped line" guess whose own comment conceded it was heuristic.
// All of it existed to answer two questions clang answers directly: what
// kind of declaration is this, and what encloses it.
cfg.AddAstLintRule("naming", [](LintContext& ctx) {
if (!IsCppFile(ctx)) return;
using Kind = Crafter::LintDeclKind;
std::span<const Crafter::LintDecl> decls = ctx.Decls();
for (const Crafter::LintDecl& decl : decls) {
if (decl.name.empty()) continue; // anonymous namespace, unnamed struct
// A declaration with C language linkage is named by the C library
// it mirrors — `extern "C" int setenv(...)` is not ours to rename.
if (decl.isExternC) continue;
// Namespace scope is now a lookup rather than a brace count, and it
// is exact for a local declared inside a function body.
bool atNamespaceScope = decl.parent == Crafter::LintNoParent
|| decls[decl.parent].kind == Kind::Namespace;
switch (decl.kind) {
case Kind::Class:
case Kind::Struct:
case Kind::Union:
case Kind::Enum:
if (!IsPascalCase(decl.name)) {
ctx.Report(decl.line, std::format("type '{}' should be PascalCase", decl.name));
}
break;
case Kind::TypeAlias:
if (!IsPascalCase(decl.name)) {
ctx.Report(decl.line, std::format("type alias '{}' should be PascalCase", decl.name));
}
break;
case Kind::Function:
case Kind::Method:
// main is spelled by the language; operators by their
// symbol. Constructors and destructors take their type's
// name and are separate kinds, so they never arrive here.
if (decl.name == "main" || decl.name.starts_with("operator")) break;
if (!IsPascalCase(decl.name)) {
ctx.Report(decl.line, std::format("function '{}' should be PascalCase", decl.name));
}
break;
case Kind::Variable:
// constexpr variables are compile-time constants and take
// constant naming, like statics and globals.
if (decl.isStatic || decl.isConstexpr || atNamespaceScope) {
if (!IsPascalCase(decl.name)) {
ctx.Report(decl.line, std::format("{} '{}' should be PascalCase",
decl.isStatic ? "static variable"
: decl.isConstexpr ? "constexpr constant"
: "global variable", decl.name));
}
} else if (!IsCamelCase(decl.name)) {
ctx.Report(decl.line, std::format("variable '{}' should be camelCase", decl.name));
}
break;
case Kind::Field:
if (decl.isStatic || decl.isConstexpr) {
if (!IsPascalCase(decl.name)) {
ctx.Report(decl.line, std::format("static member '{}' should be PascalCase", decl.name));
}
} else if (!IsCamelCase(decl.name)) {
ctx.Report(decl.line, std::format("member '{}' should be camelCase", decl.name));
}
break;
default:
break;
}
}
});
// Scoped enums only. Kept on tokens rather than moved to the AST, even
// though LintDecl carries an exact isScopedEnum: an AST is one
// configuration's slice, so a plain enum inside a preprocessor branch that
// is inactive for the host would stop being reported. Tokens are lexed
// without evaluating #if, so every platform's code stays covered.
cfg.AddLintRule("enum-class", [](LintContext& ctx) {
if (!IsCppFile(ctx)) return;
std::span<const Crafter::LintToken> tokens = ctx.Tokens();
for (std::size_t i = 0; i < tokens.size(); ++i) {
if (tokens[i].kind != Crafter::LintTokenKind::Keyword) continue;
if (ctx.TokenText(tokens[i]) != "enum") continue;
// Asking for the next TOKEN rather than the rest of the line means a
// declaration split across lines reads identically to one that is
// not — the regex this replaced required the name to follow `enum`
// on the same line, so `enum\n Color {` went unreported.
std::string_view next = i + 1 < tokens.size() ? ctx.TokenText(tokens[i + 1]) : std::string_view{};
if (next == "class" || next == "struct") continue;
ctx.Report(tokens[i].line, "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* in our own declarations.
//
// Reads the AST rather than the text, which retires the substring denylist
// this rule used to carry (argv, getenv, setenv, dlerror, c_str, .data(,
// reinterpret_cast, extern "). Every entry was a patch for one interop
// site, the list could only grow, and it disabled the rule for a whole LINE
// whenever one appeared. The question is now asked directly: whose header
// dictates this spelling? A declaration with C language linkage, or one
// that binds to an entity declared outside the project, is somebody else's
// API and keeps its spelling.
//
// Only declarations are considered. A char* inside a cast or an expression
// is not an interface, and reinterpret_cast<char*> for binary IO — the case
// the denylist existed to permit — is no longer a finding to suppress.
cfg.AddAstLintRule("no-char-pointer", [](LintContext& ctx) {
if (!IsCppFile(ctx)) return;
std::span<const Crafter::LintDecl> decls = ctx.Decls();
for (const Crafter::LintDecl& decl : decls) {
// main's signature is fixed by the language, so its argv is no more
// ours to modernise than a C API's is.
if (decl.parent != Crafter::LintNoParent && decls[decl.parent].name == "main") continue;
if (decl.kind == Crafter::LintDeclKind::Function && decl.name == "main") continue;
switch (decl.kind) {
case Crafter::LintDeclKind::Variable:
case Crafter::LintDeclKind::Parameter:
case Crafter::LintDeclKind::Field:
case Crafter::LintDeclKind::TypeAlias:
case Crafter::LintDeclKind::Function:
case Crafter::LintDeclKind::Method:
break;
default:
continue;
}
if (decl.isExternC || decl.isForeignApi) continue;
if (!IsCharPointer(decl.type)) continue;
ctx.Report(decl.line, std::format("prefer std::string / std::string_view over char* ('{}' is '{}')", decl.name, decl.type));
}
});
// 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.
// A local that is never written should say so. Restricted to SCALARS —
// integers, bools, enums, pointers, floating types — which is what makes
// the answer exact rather than a guess: a scalar has no member functions,
// so the only ways to write one are assignment, ++/--, having its address
// taken, or binding to a non-const reference, and the AST layer tracks all
// four. For a class type, a non-const method call could mutate it and
// deciding that needs the whole-program analysis clang-tidy does.
//
// Report-only. Adding const is a judgement about intent as much as
// mechanics, and a wrong suggestion should cost a glance, not a build.
cfg.AddAstLintRule("const-local", [](LintContext& ctx) {
if (!IsCppFile(ctx)) return;
std::span<const Crafter::LintDecl> decls = ctx.Decls();
for (const Crafter::LintDecl& decl : decls) {
if (decl.kind != Crafter::LintDeclKind::Variable) continue;
if (decl.parent == Crafter::LintNoParent) continue;
// Locals only: a namespace-scope or static variable may be written
// from a translation unit this parse cannot see.
Crafter::LintDeclKind enclosing = decls[decl.parent].kind;
bool isLocal = enclosing == Crafter::LintDeclKind::Function || enclosing == Crafter::LintDeclKind::Method
|| enclosing == Crafter::LintDeclKind::Constructor || enclosing == Crafter::LintDeclKind::Destructor;
if (!isLocal || decl.isStatic) continue;
if (decl.isConst || decl.isConstexpr) continue;
if (!decl.isScalar || decl.isMutated) continue;
if (decl.name.empty()) continue;
// A range-for binding is not what a reader pictures as an
// assignable variable, and `for (T* const x : …)` is not a spelling
// anybody writes.
if (decl.isLoopVariable) continue;
// Likewise `T* const p` — the useful constness for a pointer local
// is almost always on the pointee, which this rule cannot advise
// on. Restricting to value types keeps the advice actionable.
if (decl.type.contains('*')) continue;
ctx.Report(decl.line, std::format("'{}' is never modified — declare it const", decl.name));
}
});
// A constant whose value is already a constant expression can be constexpr,
// which moves it into the type system instead of leaving it to the
// optimiser. Constant-ness of the initialiser is decided by clang's own
// evaluator, so `sizeof(T)`, a fold over other constants and anything else
// that folds all qualify, while `Compute()` does not.
//
// Restricted to scalars on purpose: for a class type, constexpr may be
// unavailable even when the initialiser folds (a std::string constant
// cannot be constexpr at namespace scope), and the evaluator answering
// "this folds" is not the same question as "constexpr is legal here".
cfg.AddAstLintRule("constexpr-constant", [](LintContext& ctx) {
if (!IsCppFile(ctx)) return;
for (const Crafter::LintDecl& decl : ctx.Decls()) {
if (decl.kind != Crafter::LintDeclKind::Variable && decl.kind != Crafter::LintDeclKind::Field) continue;
if (!decl.isConst || decl.isConstexpr || !decl.isScalar) continue;
// A pointer's value is an address, which is rarely a constant
// expression and never an interesting one to promote.
if (decl.type.contains('*')) continue;
if (!decl.isConstantInitialised) continue;
if (decl.name.empty()) continue;
ctx.Report(decl.line, std::format("'{}' has a constant initialiser — declare it constexpr", decl.name));
}
});
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;
// A chain is read within one line, so a literal that spans lines
// would be sliced in half by chainEnd. Single-line raw strings are
// fine: they reduce to R"…" in the stripped view, so they fail the
// "is a plain literal" test below and travel through as an
// argument, spelling and all.
bool spansLines = ctx.LineHasMultiLineToken(li + 1);
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 (spansLines) {
ctx.Report(li + 1, "use std::format instead of string concatenation with + (multi-line literal, 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.AddAstLintRule("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;
// Byte ranges whose integer spelling is not ours to change. A wrong
// rewrite here does not merely over-report — it produces code that no
// longer matches the API it is calling — so this is derived from the
// AST rather than from substrings on the line.
//
// Replaces the old per-LINE textual exemption (`int main`, `argc`,
// `argv`, `extern "`), which both missed cases and disabled the rule
// for everything else sharing a line with one of those words.
std::vector<std::pair<std::size_t, std::size_t>> protectedRanges;
for (const Crafter::LintDecl& decl : ctx.Decls()) {
if (decl.isExternC || decl.isForeignApi) {
protectedRanges.emplace_back(decl.begin, decl.end);
continue;
}
// main's signature is fixed by the language. Only the signature:
// its body is ordinary code, and the declaration's extent covers
// the whole function.
if (decl.kind == Crafter::LintDeclKind::Function && decl.name == "main") {
std::size_t bodyBrace = ctx.content.find('{', decl.begin);
protectedRanges.emplace_back(decl.begin, bodyBrace == std::string::npos ? decl.end : bodyBrace);
}
}
auto isProtected = [&protectedRanges](std::size_t offset) {
return std::any_of(protectedRanges.begin(), protectedRanges.end(),
[offset](const std::pair<std::size_t, std::size_t>& range) {
return offset >= range.first && offset < range.second;
});
};
// 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);
std::size_t pos = 0;
while (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;
if (isProtected(lineStart + runBegin)) 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.AddAstLintRule("single-declaration", [](LintContext& ctx) {
if (!IsCppFile(ctx)) return;
std::span<const Crafter::LintDecl> decls = ctx.Decls();
std::span<const Crafter::LintToken> tokens = ctx.Tokens();
struct Edit { std::size_t begin; std::size_t end; std::string text; };
std::vector<Edit> edits;
for (std::size_t i = 0; i < decls.size(); ++i) {
const Crafter::LintDecl& head = decls[i];
if (head.kind != Crafter::LintDeclKind::Variable && head.kind != Crafter::LintDeclKind::Field) continue;
// A group head owns the shared type, so its extent starts before
// its name. Continuation declarators start AT their name.
if (head.begin == head.nameOffset) continue;
std::size_t last = i;
while (last + 1 < decls.size()) {
const Crafter::LintDecl& next = decls[last + 1];
if (next.kind != head.kind || next.parent != head.parent) break;
if (next.begin != next.nameOffset) break; // starts a new statement
++last;
}
if (last == i) continue; // a single declarator: nothing to split
// The statement runs to the ';' after the final declarator.
auto semicolon = std::ranges::find_if(tokens, [&](const Crafter::LintToken& t) {
return t.offset >= decls[last].end && ctx.TokenText(t) == ";";
});
if (semicolon == tokens.end()) continue;
std::size_t stmtEnd = semicolon->offset + 1;
// A comment anywhere inside the statement would be swallowed by the
// rewrite. One AFTER the ';' is outside the replaced range and
// survives, which the line-based version could not manage — it
// refused the whole line.
bool hasInnerComment = std::ranges::any_of(tokens, [&](const Crafter::LintToken& t) {
return t.kind == Crafter::LintTokenKind::Comment && t.offset >= head.begin && t.offset < stmtEnd;
});
if (hasInnerComment) continue;
if (ctx.Suppressed("single-declaration", head.line)) continue;
// Indent from the head's own line, so a statement that starts
// mid-line is left alone rather than reflowed.
std::size_t lineBegin = ctx.content.rfind('\n', head.begin);
lineBegin = lineBegin == std::string::npos ? 0 : lineBegin + 1;
if (!Trim(std::string_view(ctx.content).substr(lineBegin, head.begin - lineBegin)).empty()) continue;
std::string indent(std::string_view(ctx.content).substr(lineBegin, head.begin - lineBegin));
std::string replacement;
for (std::size_t d = i; d <= last; ++d) {
// Each declarator gets its OWN type. This is the whole reason
// this rule needed the AST: copying the head's type prefix
// turns `int* a, b;` into `int* a; int* b;` and silently
// changes b's type. clang has already resolved b as plain int.
std::string type = NormalisePointerSpelling(decls[d].type);
std::string_view declarator = std::string_view(ctx.content).substr(decls[d].nameOffset, decls[d].end - decls[d].nameOffset);
if (d > i) replacement += std::format("\n{}", indent);
// NormalisePointerSpelling already attached the star to the
// type, so the separator is always a single space: `int* a`.
replacement += std::format("{} {};", type, Trim(declarator));
}
edits.push_back({head.begin, stmtEnd, std::move(replacement)});
i = last;
}
if (edits.empty()) return;
std::string out = ctx.content;
std::ranges::sort(edits, [](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.text);
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.LineHasComment(i + 1) || (i > 0 && ctx.LineHasComment(i));
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.LineHasComment(i + 1) && !ctx.LineHasComment(i + 2)
&& !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.LineHasComment(i + 1) && !ctx.LineHasMultiLineToken(i + 1);
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.LineHasComment(j + 1) || ctx.LineHasMultiLineToken(j + 1)) {
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.LineHasComment(i + 1) && !ctx.LineHasMultiLineToken(i + 1)) {
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.LineHasComment(j + 1) || ctx.LineHasMultiLineToken(j + 1)) {
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