Function addIncludeIgnoredPatterns

src/project-config.ts:359–396

(rootDir: string, patterns: string[])

 * index in the same process sees the new patterns.
 */
export function addIncludeIgnoredPatterns(rootDir: string, patterns: string[]): number {
  const file = path.join(rootDir, PROJECT_CONFIG_FILENAME);
  let config: Record<string, unknown> = {};
  let raw: string | null = null;
  try {
    raw = fs.readFileSync(file, 'utf-8');
  } catch {
    raw = null; // missing file — create a fresh one below
  }
  if (raw !== null) {
    let parsed: unknown;
    try {
      parsed = JSON.parse(raw);
    } catch {
      throw new Error(`${PROJECT_CONFIG_FILENAME} is not valid JSON — fix it by hand, then re-run.`);
    }
    if (parsed && typeof parsed === 'object' && !Array.isArray(parsed)) {
      config = parsed as Record<string, unknown>;
    }
  }

  const existing = Array.isArray(config.includeIgnored)
    ? (config.includeIgnored as unknown[]).filter((p): p is string => typeof p === 'string')
    : [];
  const merged = [...existing];
  const seen = new Set(existing);
  let added = 0;
  for (const p of patterns) {
    if (seen.has(p)) continue;
    seen.add(p);
    merged.push(p);
    added++;
  }
  config.includeIgnored = merged;
  fs.writeFileSync(file, JSON.stringify(config, null, 2) + '\n');
  clearProjectConfigCache();
  return added;
}