introduce install state v2 to replace v1

the v1 state is unnecessary since new repos are created for new additional_dependencies

pre_commit/constants.py

@@ -5,8 +5,6 @@ import importlib.metadata
 CONFIG_FILE = '.pre-commit-config.yaml'
 MANIFEST_FILE = '.pre-commit-hooks.yaml'
 
-# Bump when installation changes in a backwards / forwards incompatible way
-INSTALLED_STATE_VERSION = '1'
 # Bump when modifying `empty_template`
 LOCAL_REPO_VERSION = '1'
 

pre_commit/repository.py

@@ -23,16 +23,20 @@ from pre_commit.util import rmtree
 logger = logging.getLogger('pre_commit')
 
 
+def _state_filename_v1(venv: str) -> str:
+    return os.path.join(venv, '.install_state_v1')
+
+
+def _state_filename_v2(venv: str) -> str:
+    return os.path.join(venv, '.install_state_v2')
+
+
 def _state(additional_deps: Sequence[str]) -> object:
     return {'additional_dependencies': sorted(additional_deps)}
 
 
-def _state_filename(venv: str) -> str:
-    return os.path.join(venv, f'.install_state_v{C.INSTALLED_STATE_VERSION}')
-
-
 def _read_state(venv: str) -> object | None:
-    filename = _state_filename(venv)
+    filename = _state_filename_v1(venv)
     if not os.path.exists(filename):
         return None
     else:
@@ -51,7 +55,10 @@ def _hook_installed(hook: Hook) -> bool:
         hook.language_version,
     )
     return (
-        _read_state(venv) == _state(hook.additional_dependencies) and
+        (
+            os.path.exists(_state_filename_v2(venv)) or
+            _read_state(venv) == _state(hook.additional_dependencies)
+        ) and
         not lang.health_check(hook.prefix, hook.language_version)
     )
 
@@ -87,14 +94,18 @@ def _hook_install(hook: Hook) -> None:
                 f'your environment\n\n'
                 f'more info:\n\n{health_error}',
             )
+
+        # TODO: remove v1 state writing, no longer needed after pre-commit 3.0
         # Write our state to indicate we're installed
-        state_filename = _state_filename(venv)
+        state_filename = _state_filename_v1(venv)
         staging = f'{state_filename}staging'
         with open(staging, 'w') as state_file:
             state_file.write(json.dumps(_state(hook.additional_dependencies)))
         # Move the file into place atomically to indicate we've installed
         os.replace(staging, state_filename)
 
+        open(_state_filename_v2(venv), 'a+').close()
+
 
 def _hook(
         *hook_dicts: dict[str, Any],

tests/repository_test.py

@@ -23,6 +23,7 @@ from pre_commit.languages import ruby
 from pre_commit.languages import rust
 from pre_commit.languages.all import languages
 from pre_commit.prefix import Prefix
+from pre_commit.repository import _hook_installed
 from pre_commit.repository import all_hooks
 from pre_commit.repository import install_hook_envs
 from pre_commit.util import cmd_output
@@ -562,6 +563,21 @@ def test_additional_dependencies_roll_forward(tempdir_factory, store):
         assert 'mccabe' not in cmd_output('pip', 'freeze', '-l')[1]
 
 
+@pytest.mark.parametrize('v', ('v1', 'v2'))
+def test_repository_state_compatibility(tempdir_factory, store, v):
+    path = make_repo(tempdir_factory, 'python_hooks_repo')
+
+    config = make_config_from_repo(path)
+    hook = _get_hook(config, store, 'foo')
+    envdir = helpers.environment_dir(
+        hook.prefix,
+        python.ENVIRONMENT_DIR,
+        hook.language_version,
+    )
+    os.remove(os.path.join(envdir, f'.install_state_{v}'))
+    assert _hook_installed(hook) is True
+
+
 def test_additional_ruby_dependencies_installed(tempdir_factory, store):
     path = make_repo(tempdir_factory, 'ruby_hooks_repo')
     config = make_config_from_repo(path)