Some minor fixups

pre_commit/meta_hooks/check_useless_excludes.py

@@ -4,11 +4,15 @@ import argparse
 import re
 
 import pre_commit.constants as C
+from pre_commit import git
 from pre_commit.clientlib import load_config
-from pre_commit.git import get_all_files
+from pre_commit.clientlib import MANIFEST_HOOK_DICT
+from pre_commit.schema import apply_defaults
 
 
 def exclude_matches_any(filenames, include, exclude):
+    if exclude == '^$':
+        return True
     include_re, exclude_re = re.compile(include), re.compile(exclude)
     for filename in filenames:
         if include_re.search(filename) and exclude_re.search(filename):
@@ -18,28 +22,31 @@ def exclude_matches_any(filenames, include, exclude):
 
 def check_useless_excludes(config_file):
     config = load_config(config_file)
-    files = get_all_files()
-    useless_excludes = False
+    files = git.get_all_files()
+    retv = 0
 
-    exclude = config.get('exclude')
-    if exclude != '^$' and not exclude_matches_any(files, '', exclude):
+    exclude = config['exclude']
+    if not exclude_matches_any(files, '', exclude):
         print(
             'The global exclude pattern {!r} does not match any files'
             .format(exclude),
         )
-        useless_excludes = True
+        retv = 1
 
     for repo in config['repos']:
         for hook in repo['hooks']:
-            include, exclude = hook.get('files', ''), hook.get('exclude')
-            if exclude and not exclude_matches_any(files, include, exclude):
+            # Not actually a manifest dict, but this more accurately reflects
+            # the defaults applied during runtime
+            hook = apply_defaults(hook, MANIFEST_HOOK_DICT)
+            include, exclude = hook['files'], hook['exclude']
+            if not exclude_matches_any(files, include, exclude):
                 print(
                     'The exclude pattern {!r} for {} does not match any files'
                     .format(exclude, hook['id']),
                 )
-                useless_excludes = True
+                retv = 1
 
-    return useless_excludes
+    return retv
 
 
 def main(argv=None):