precommit
diff --git a/‎pre_commit/languages/all.py‎
Lines changed: 41 additions & 52 deletions b/‎pre_commit/languages/all.py‎
Lines changed: 41 additions & 52 deletions
diff --git a/‎pre_commit/repository.py‎
Lines changed: 1 addition & 0 deletions b/‎pre_commit/repository.py‎
Lines changed: 1 addition & 0 deletions
diff --git a/‎testing/gen-languages-all‎
Lines changed: 27 additions & 0 deletions b/‎testing/gen-languages-all‎
Lines changed: 27 additions & 0 deletions
diff --git a/‎tests/languages/all_test.py‎
Lines changed: 0 additions & 62 deletions b/‎tests/languages/all_test.py‎
Lines changed: 0 additions & 62 deletions
@@ -1,5 +1,9 @@
-from typing import Any
-from typing import Dict
+from typing import Callable
+from typing import NamedTuple
+from typing import Optional
+from typing import Sequence
+from typing import Tuple
+from typing import TYPE_CHECKING
 
 from pre_commit.languages import conda
 from pre_commit.languages import docker
@@ -15,58 +19,43 @@
 from pre_commit.languages import script
 from pre_commit.languages import swift
 from pre_commit.languages import system
+from pre_commit.prefix import Prefix
 
+if TYPE_CHECKING:
+    from pre_commit.repository import Hook
 
-# A language implements the following constant and functions in its module:
-#
-# # Use None for no environment
-# ENVIRONMENT_DIR = 'foo_env'
-#
-# def get_default_version():
-#     """Return a value to replace the 'default' value for language_version.
-#
-#     return 'default' if there is no better option.
-#    """
-#
-# def healthy(prefix, language_version):
-#     """Return whether or not the environment is considered functional."""
-#
-# def install_environment(prefix, version, additional_dependencies):
-#     """Installs a repository in the given repository.  Note that the current
-#     working directory will already be inside the repository.
-#
-#     Args:
-#         prefix - `Prefix` bound to the repository.
-#         version - A version specified in the hook configuration or 'default'.
-#     """
-#
-# def run_hook(hook, file_args, color):
-#     """Runs a hook and returns the returncode and output of running that
-#     hook.
-#
-#     Args:
-#         hook - `Hook`
-#         file_args - The files to be run
-#         color - whether the hook should be given a pty (when supported)
-#
-#     Returns:
-#         (returncode, output)
-#     """
 
-languages: Dict[str, Any] = {
-    'conda': conda,
-    'docker': docker,
-    'docker_image': docker_image,
-    'fail': fail,
-    'golang': golang,
-    'node': node,
-    'pygrep': pygrep,
-    'python': python,
-    'python_venv': python_venv,
-    'ruby': ruby,
-    'rust': rust,
-    'script': script,
-    'swift': swift,
-    'system': system,
+class Language(NamedTuple):
+    name: str
+    # Use `None` for no installation / environment
+    ENVIRONMENT_DIR: Optional[str]
+    # return a value to replace `'default` for `language_version`
+    get_default_version: Callable[[], str]
+    # return whether the environment is healthy (or should be rebuilt)
+    healthy: Callable[[Prefix, str], bool]
+    # install a repository for the given language and language_version
+    install_environment: Callable[[Prefix, str, Sequence[str]], None]
+    # execute a hook and return the exit code and output
+    run_hook: 'Callable[[Hook, Sequence[str], bool], Tuple[int, bytes]]'
+
+
+# TODO: back to modules + Protocol: https://github.com/python/mypy/issues/5018
+languages = {
+    # BEGIN GENERATED (testing/gen-languages-all)
+    'conda': Language(name='conda', ENVIRONMENT_DIR=conda.ENVIRONMENT_DIR, get_default_version=conda.get_default_version, healthy=conda.healthy, install_environment=conda.install_environment, run_hook=conda.run_hook),  # noqa: E501
+    'docker': Language(name='docker', ENVIRONMENT_DIR=docker.ENVIRONMENT_DIR, get_default_version=docker.get_default_version, healthy=docker.healthy, install_environment=docker.install_environment, run_hook=docker.run_hook),  # noqa: E501
+    'docker_image': Language(name='docker_image', ENVIRONMENT_DIR=docker_image.ENVIRONMENT_DIR, get_default_version=docker_image.get_default_version, healthy=docker_image.healthy, install_environment=docker_image.install_environment, run_hook=docker_image.run_hook),  # noqa: E501
+    'fail': Language(name='fail', ENVIRONMENT_DIR=fail.ENVIRONMENT_DIR, get_default_version=fail.get_default_version, healthy=fail.healthy, install_environment=fail.install_environment, run_hook=fail.run_hook),  # noqa: E501
+    'golang': Language(name='golang', ENVIRONMENT_DIR=golang.ENVIRONMENT_DIR, get_default_version=golang.get_default_version, healthy=golang.healthy, install_environment=golang.install_environment, run_hook=golang.run_hook),  # noqa: E501
+    'node': Language(name='node', ENVIRONMENT_DIR=node.ENVIRONMENT_DIR, get_default_version=node.get_default_version, healthy=node.healthy, install_environment=node.install_environment, run_hook=node.run_hook),  # noqa: E501
+    'pygrep': Language(name='pygrep', ENVIRONMENT_DIR=pygrep.ENVIRONMENT_DIR, get_default_version=pygrep.get_default_version, healthy=pygrep.healthy, install_environment=pygrep.install_environment, run_hook=pygrep.run_hook),  # noqa: E501
+    'python': Language(name='python', ENVIRONMENT_DIR=python.ENVIRONMENT_DIR, get_default_version=python.get_default_version, healthy=python.healthy, install_environment=python.install_environment, run_hook=python.run_hook),  # noqa: E501
+    'python_venv': Language(name='python_venv', ENVIRONMENT_DIR=python_venv.ENVIRONMENT_DIR, get_default_version=python_venv.get_default_version, healthy=python_venv.healthy, install_environment=python_venv.install_environment, run_hook=python_venv.run_hook),  # noqa: E501
+    'ruby': Language(name='ruby', ENVIRONMENT_DIR=ruby.ENVIRONMENT_DIR, get_default_version=ruby.get_default_version, healthy=ruby.healthy, install_environment=ruby.install_environment, run_hook=ruby.run_hook),  # noqa: E501
+    'rust': Language(name='rust', ENVIRONMENT_DIR=rust.ENVIRONMENT_DIR, get_default_version=rust.get_default_version, healthy=rust.healthy, install_environment=rust.install_environment, run_hook=rust.run_hook),  # noqa: E501
+    'script': Language(name='script', ENVIRONMENT_DIR=script.ENVIRONMENT_DIR, get_default_version=script.get_default_version, healthy=script.healthy, install_environment=script.install_environment, run_hook=script.run_hook),  # noqa: E501
+    'swift': Language(name='swift', ENVIRONMENT_DIR=swift.ENVIRONMENT_DIR, get_default_version=swift.get_default_version, healthy=swift.healthy, install_environment=swift.install_environment, run_hook=swift.run_hook),  # noqa: E501
+    'system': Language(name='system', ENVIRONMENT_DIR=system.ENVIRONMENT_DIR, get_default_version=system.get_default_version, healthy=system.healthy, install_environment=system.install_environment, run_hook=system.run_hook),  # noqa: E501
+    # END GENERATED
 }
 all_languages = sorted(languages)
@@ -113,6 +113,7 @@ def install(self) -> None:
         logger.info('This may take a few minutes...')
 
         lang = languages[self.language]
+        assert lang.ENVIRONMENT_DIR is not None
         venv = environment_dir(lang.ENVIRONMENT_DIR, self.language_version)
 
         # There's potentially incomplete cleanup from previous runs
 
@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+import sys
+
+LANGUAGES = [
+    'conda', 'docker', 'docker_image', 'fail', 'golang', 'node', 'pygrep',
+    'python', 'python_venv', 'ruby', 'rust', 'script', 'swift', 'system',
+]
+FIELDS = [
+    'ENVIRONMENT_DIR', 'get_default_version', 'healthy', 'install_environment',
+    'run_hook',
+]
+
+
+def main() -> int:
+    print(f'    # BEGIN GENERATED ({sys.argv[0]})')
+    for lang in LANGUAGES:
+        parts = [f'    {lang!r}: Language(name={lang!r}']
+        for k in FIELDS:
+            parts.append(f', {k}={lang}.{k}')
+        parts.append('),  # noqa: E501')
+        print(''.join(parts))
+    print('    # END GENERATED')
+    return 0
+
+
+if __name__ == '__main__':
+    exit(main())