Function loadCppIncludeDirsFromCompileDB

src/resolution/import-resolver.ts:367–433

* Try to load include directories from compile_commands.json. * Returns null if no compilation database is found (so the heuristic * fallback can run). Returns an array (possibly empty) otherwise.

(projectRoot: string)

 * fallback can run). Returns an array (possibly empty) otherwise.
 */
function loadCppIncludeDirsFromCompileDB(projectRoot: string): string[] | null {
  const candidates = [
    path.join(projectRoot, 'compile_commands.json'),
    path.join(projectRoot, 'build', 'compile_commands.json'),
    path.join(projectRoot, 'cmake-build-debug', 'compile_commands.json'),
    path.join(projectRoot, 'cmake-build-release', 'compile_commands.json'),
    path.join(projectRoot, 'out', 'compile_commands.json'),
  ];

  let dbPath: string | undefined;
  for (const c of candidates) {
    try {
      if (fs.existsSync(c)) {
        dbPath = c;
        break;
      }
    } catch {
      // ignore
    }
  }
  if (!dbPath) return null;

  try {
    const content = fs.readFileSync(dbPath, 'utf-8');
    const entries = JSON.parse(content) as Array<{
      directory: string;
      command?: string;
      arguments?: string[];
    }>;
    if (!Array.isArray(entries)) return null;

    const dirSet = new Set<string>();
    for (const entry of entries) {
      const dir = entry.directory || projectRoot;
      const args = entry.arguments || (entry.command ? shlexSplit(entry.command) : []);
      for (let i = 0; i < args.length; i++) {
        const arg = args[i]!;
        let includeDir: string | undefined;
        // -I<dir> (no space)
        if (arg.startsWith('-I') && arg.length > 2) {
          includeDir = arg.substring(2);
        }
        // -isystem <dir> (space-separated)
        else if ((arg === '-isystem' || arg === '-I') && i + 1 < args.length) {
          includeDir = args[i + 1];
          i++; // skip next arg
        }
        if (includeDir) {
          // Normalize: resolve relative to the compilation directory
          const absPath = path.isAbsolute(includeDir)
            ? includeDir
            : path.resolve(dir, includeDir);
          const relPath = path.relative(projectRoot, absPath).replace(/\\/g, '/');
          // Skip system directories and paths outside the project
          // (relative paths starting with .. or absolute paths like
          // /usr/include or C:\usr on Windows)
          if (!relPath.startsWith('..') && relPath.length > 0 && !path.isAbsolute(relPath)) {
            dirSet.add(relPath);