mps-pre-commit-hooks

Reusable pre-commit / prek hooks for JetBrains MPS projects.

MPS keeps a lot of its project structure in files that are easy to leave in an inconsistent state by hand or by a bad merge: a module added on disk but never registered in .mps/modules.xml, a model dropped outside every model root, a descriptor renamed but not its folder. MPS silently ignores most of these, so the mistake only surfaces much later. These hooks catch them at commit time.

Usage

Add the repo to your project's .pre-commit-config.yaml:

repos:
  - repo: https://github.com/specificlanguages/mps-pre-commit-hooks
    rev: v0.1.0
    hooks:
      - id: mps-check-orphan-modules
      - id: mps-check-unbuilt-modules
      - id: mps-check-missing-modules
      - id: mps-check-orphan-models
      - id: mps-check-orphan-mpsr-files
      - id: mps-check-zero-sized-xmls
      - id: mps-check-module-naming
      - id: mps-check-path-variables

Then pre-commit install (or just prek install). The hooks work the same under both runners.

Each hook is independent — enable only the ones you want. They all scan the whole repository (not just the staged files), since most of what they check are cross-file relationships. The structural checks (orphans, and missing/dangling references) run on every commit, because the problem they catch is often introduced by a commit that only deletes a file — which pre-commit would otherwise skip them for. The per-file content checks (zero-sized, naming, path variables) run only when a relevant file is added or changed.

Hooks

mps-check-orphan-modules

Reports orphan modules — *.msd / *.mpl / *.devkit / *.mpst files present on disk but not registered in any .mps/modules.xml. MPS opens a project from its modules.xml, so it silently ignores an unregistered module, and the mistake otherwise surfaces only much later.

mps-check-unbuilt-modules

Reports unbuilt modules — modules that are not mentioned in any MPS build script.

Exclude demo and sandbox modules with --exclude:

- id: mps-check-unbuilt-modules
  args: [--exclude=/code/applications, --exclude=_spreferences, --exclude=*.sandbox.msd]

mps-check-missing-modules / mps-fix-missing-modules

The reverse of the orphan-modules check: reports .mps/modules.xml entries whose modulePath points to a file that no longer exists on disk (typically left behind when a module is moved or deleted). Entries addressed through a path variable are ignored.

mps-check-missing-modules is read-only — it reports and fails. mps-fix-missing-modules removes the dangling <modulePath> entries from their modules.xml; use it when you want the hook to repair them for you:

- id: mps-fix-missing-modules

These are defined as separate hooks because the check hook may run in parallel with other read-only hooks whereas the fix hook requires serial execution (require_serial: true).

mps-check-orphan-models

Reports model files (*.mps / *.mpsr / .model) living outside every module's declared default model root. A model outside any root is invisible to MPS — present on disk but never loaded — usually the result of a move that didn't update the owning module, or a stray copy.

mps-check-orphan-mpsr-files

Reports *.mpsr files whose directory has no .model header file alongside them. The header describes the model; without it MPS cannot load the roots, so the model is effectively lost.

mps-check-zero-sized-xmls

Reports tracked MPS XML files that are zero bytes — model files (*.mps / *.mpsr / .model), module descriptors (*.msd / *.mpl / *.devkit / *.mpst), and the per-project .mps/modules.xml / .mps/libraries.xml. A zero-byte file here is almost always the result of a botched save, merge, or checkout; MPS won't load it, silently dropping whatever it held.

mps-check-module-naming

Checks that every module descriptor (*.msd / *.mpl / *.devkit / *.mpst) agrees with its layout on disk. The directory and the file must be named after the full module name: com.example.foo must be located in com.example.foo/com.example.foo.mpl (likewise for other module types).

Modules can be excluded with --exclude, a repeatable glob written like a .gitignore pattern:

- id: mps-check-module-naming
  args: [--exclude=_spreferences, --exclude=some.lang/sandbox]

mps-check-path-variables / mps-fix-path-variables

Reports path variables in .mps/libraries.xml and .mps/modules.xml. Replacing these paths with project-relative paths makes it easier to check out and open the project.

mps-check-path-variables is check-only, it fails if a path variable is found. mps-fix-path-variables rewrites the offending paths in place; use it when you want the hook to repair them for you:

- id: mps-fix-path-variables

These are defined as separate hooks because the check hook may run in parallel with other read-only hooks whereas the fix hook requires serial execution (require_serial: true).

The fix assumes the macro's value is the Git repository root and re-expresses the whole path relative to $PROJECT_DIR$:

${mbeddr.github.core.home}/code/platform/com.mbeddr.doc
→ $PROJECT_DIR$/../../platform/com.mbeddr.doc

Caveat. This assumption holds for the common case where a variable points at the project's own checkout root. In other cases the rewritten path will be incorrect. Like other pre-commit fixers, the hook exits non-zero when it changes files, so you re-stage them deliberately.

License

MIT. See LICENSE.