The extension → language table was hardcoded, so a codebase using a
non-standard extension for a supported language (e.g. `.dota_lua` for Lua)
had those files silently skipped — no way to opt them in short of patching
the source.
Add an opt-in, project-scoped `codegraph.json` at the repo root:
{ "extensions": { ".dota_lua": "lua", ".tpl": "php" } }
Mappings merge on top of the built-in defaults and take precedence (so a
built-in can be re-pointed, e.g. `.h` → `cpp`). Absent or malformed config
is the zero-config default — byte-identical to prior behavior; an invalid
target language or unparseable file is warned-and-skipped, never fatal.
Implementation:
- New `src/project-config.ts` — `loadExtensionOverrides(rootDir)`, validated
against `isLanguageSupported`, mtime-cached per root.
- `detectLanguage` / `isSourceFile` gain an optional `overrides` arg
(omitting it is the existing behavior).
- Overrides threaded per-operation through every extraction call site
(scan/walk gates, git change-detection, grammar selection, extraction,
the file watcher), resolved from the project root — no process-global
state, so the multi-project daemon stays isolated. The parse worker
receives the resolved language in its message.
Tests: 13 new cases (unit, loader validation/normalization/caching, and a
full-index integration proving a custom-extension file is extracted while
the zero-config path indexes nothing). Worker path smoke-tested via the
built CLI.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
