add warning for deprecated stages values in default_stages

pre_commit/clientlib.py

@@ -125,6 +125,32 @@ class DeprecatedStagesWarning(NamedTuple):
         raise NotImplementedError
 
 
+class DeprecatedDefaultStagesWarning(NamedTuple):
+    key: str
+
+    def check(self, dct: dict[str, Any]) -> None:
+        if self.key not in dct:
+            return
+
+        val = dct[self.key]
+        cfgv.check_array(cfgv.check_any)(val)
+
+        legacy_stages = [stage for stage in val if stage in _STAGES]
+        if legacy_stages:
+            logger.warning(
+                f'top-level `default_stages` uses deprecated stage names '
+                f'({", ".join(legacy_stages)}) which will be removed in a '
+                f'future version.  '
+                f'run: `pre-commit migrate-config` to automatically fix this.',
+            )
+
+    def apply_default(self, dct: dict[str, Any]) -> None:
+        pass
+
+    def remove_default(self, dct: dict[str, Any]) -> None:
+        raise NotImplementedError
+
+
 MANIFEST_HOOK_DICT = cfgv.Map(
     'Hook', 'id',
 
@@ -398,6 +424,7 @@ CONFIG_SCHEMA = cfgv.Map(
         'default_language_version', DEFAULT_LANGUAGE_VERSION, {},
     ),
     StagesMigration('default_stages', STAGES),
+    DeprecatedDefaultStagesWarning('default_stages'),
     cfgv.Optional('files', check_string_regex, ''),
     cfgv.Optional('exclude', check_string_regex, '^$'),
     cfgv.Optional('fail_fast', cfgv.check_bool, False),

tests/clientlib_test.py

@@ -335,6 +335,30 @@ def test_no_warning_for_non_deprecated_stages(caplog):
     assert caplog.record_tuples == []
 
 
+def test_warning_for_deprecated_default_stages(caplog):
+    cfg = {'default_stages': ['commit', 'push'], 'repos': []}
+
+    cfgv.validate(cfg, CONFIG_SCHEMA)
+
+    assert caplog.record_tuples == [
+        (
+            'pre_commit',
+            logging.WARNING,
+            'top-level `default_stages` uses deprecated stage names '
+            '(commit, push) which will be removed in a future version.  '
+            'run: `pre-commit migrate-config` to automatically fix this.',
+        ),
+    ]
+
+
+def test_no_warning_for_non_deprecated_default_stages(caplog):
+    cfg = {'default_stages': ['pre-commit', 'pre-push'], 'repos': []}
+
+    cfgv.validate(cfg, CONFIG_SCHEMA)
+
+    assert caplog.record_tuples == []
+
+
 @pytest.mark.parametrize(
     'manifest_obj',
     (