Make the config validator more strict for correct regexes

example_pre-commit-config.yaml

@@ -5,10 +5,10 @@
     hooks:
         -
             id: pyflakes
-            files: '*.py'
+            files: '\.py$'
         -
             id: jslint
-            files: '*.js'
+            files: '\.js$'
         -
             id: trim_trailing_whitespace
-            files: '*.py'
+            files: '\.py$'

pre_commit/clientlib/validate_config.py

@@ -2,6 +2,7 @@
 from __future__ import print_function
 
 import argparse
+import re
 
 import pre_commit.constants as C
 from pre_commit.clientlib.validate_base import get_validator
@@ -41,10 +42,24 @@ CONFIG_JSON_SCHEMA = {
 }
 
 
+def validate_config_extra(config):
+    for repo in config:
+        for hook in repo['hooks']:
+            try:
+                re.compile(hook['files'])
+            except re.error:
+                raise InvalidConfigError(
+                    'Invalid file regex at {0}, {1}: {2}'.format(
+                        repo['repo'], hook['id'], hook['files'],
+                    )
+                )
+
+
 validate_config = get_validator(
     C.CONFIG_FILE,
     CONFIG_JSON_SCHEMA,
     InvalidConfigError,
+    additional_validation_strategy=validate_config_extra,
 )
 
 
@@ -69,4 +84,4 @@ def run(argv):
             print(str(e.args[1]))
         return 1
 
-    return 0
+    return 0

tests/clientlib/validate_config_test.py

@@ -4,7 +4,9 @@ import jsonschema.exceptions
 import pytest
 
 from pre_commit.clientlib.validate_config import CONFIG_JSON_SCHEMA
+from pre_commit.clientlib.validate_config import InvalidConfigError
 from pre_commit.clientlib.validate_config import run
+from pre_commit.clientlib.validate_config import validate_config_extra
 
 
 def test_returns_0_for_valid_config():
@@ -18,6 +20,7 @@ def test_returns_0_for_out_manifest():
 def test_returns_1_for_failing():
     assert run(['tests/data/valid_yaml_but_invalid_config.yaml']) == 1
 
+
 def is_valid_according_to_schema(obj, schema):
     try:
         jsonschema.validate(obj, schema)
@@ -58,4 +61,18 @@ def is_valid_according_to_schema(obj, schema):
 ))
 def test_is_valid_according_to_schema(manifest_obj, expected):
     ret = is_valid_according_to_schema(manifest_obj, CONFIG_JSON_SCHEMA)
-    assert ret is expected
+    assert ret is expected
+
+
+def test_config_with_failing_regexes_fails():
+    with pytest.raises(InvalidConfigError):
+        # Note the regex '(' is invalid (unbalanced parens)
+        validate_config_extra(
+            [{'repo': 'foo', 'hooks': [{'id': 'hook_id', 'files': '('}]}]
+        )
+
+
+def test_config_with_ok_regexes_passes():
+    validate_config_extra(
+        [{'repo': 'foo', 'hooks': [{'id': 'hook_id', 'files': '\.py$'}]}]
+    )