Apply defaults to all of the configs. Much fewer .get()s

pre_commit/clientlib/validate_base.py

@@ -4,6 +4,8 @@ import jsonschema.exceptions
 import os.path
 import yaml
 
+from pre_commit.jsonschema_extensions import apply_defaults
+
 
 def get_validator(
     json_schema,
@@ -39,6 +41,8 @@ def get_validator(
                 'File {0} is not a valid file'.format(filename), e,
             )
 
+        obj = apply_defaults(obj, json_schema)
+
         additional_validation_strategy(obj)
 
         return obj

pre_commit/clientlib/validate_config.py

@@ -28,10 +28,10 @@ CONFIG_JSON_SCHEMA = {
                     'properties': {
                         'id': {'type': 'string'},
                         'files': {'type': 'string'},
-                        'exclude': {'type': 'string'},
+                        'exclude': {'type': 'string', 'default': '^$'},
                         'args': {
                             'type': 'array',
-                            'minItems': 1,
+                            'default': [],
                             'items': {'type': 'string'},
                         },
                     },
@@ -59,7 +59,7 @@ def validate_config_extra(config):
     for repo in config:
         for hook in repo['hooks']:
             try_regex(repo, hook['id'], hook['files'], 'files')
-            try_regex(repo, hook['id'], hook.get('exclude', ''), 'exclude')
+            try_regex(repo, hook['id'], hook['exclude'], 'exclude')
 
 
 load_config = get_validator(

pre_commit/clientlib/validate_manifest.py

@@ -20,10 +20,10 @@ MANIFEST_JSON_SCHEMA = {
         'properties': {
             'id': {'type': 'string'},
             'name': {'type': 'string'},
-            'description': {'type': 'string'},
+            'description': {'type': 'string', 'default': ''},
             'entry': {'type': 'string'},
             'language': {'type': 'string'},
-            'expected_return_value': {'type': 'number'},
+            'expected_return_value': {'type': 'number', 'default': 0},
         },
         'required': ['id', 'name', 'entry', 'language'],
     },
@@ -32,11 +32,9 @@ MANIFEST_JSON_SCHEMA = {
 
 def additional_manifest_check(obj):
     for hook_config in obj:
-        language = hook_config.get('language')
+        language = hook_config['language']
 
-        if language is not None and not any(
-            language.startswith(lang) for lang in all_languages
-        ):
+        if not any(language.startswith(lang) for lang in all_languages):
             raise InvalidManifestError(
                 'Expected language {0} for {1} to start with one of {2!r}'.format(
                     hook_config['id'],

pre_commit/languages/helpers.py

@@ -2,7 +2,7 @@
 
 def run_hook(env, hook, file_args):
     return env.run(
-        ' '.join(['xargs', hook['entry']] + hook.get('args', [])),
+        ' '.join(['xargs', hook['entry']] + hook['args']),
         stdin='\n'.join(list(file_args) + ['']),
         retcode=None,
     )

pre_commit/languages/script.py

@@ -6,7 +6,7 @@ def install_environment(repo_cmd_runner):
 
 def run_hook(repo_cmd_runner, hook, file_args):
     return repo_cmd_runner.run(
-        ['xargs', '{{prefix}}{0}'.format(hook['entry'])] + hook.get('args', []),
+        ['xargs', '{{prefix}}{0}'.format(hook['entry'])] + hook['args'],
         # TODO: this is duplicated in pre_commit/languages/helpers.py
         stdin='\n'.join(list(file_args) + ['']),
         retcode=None,

pre_commit/languages/system.py

@@ -6,7 +6,7 @@ def install_environment(repo_cmd_runner):
 
 def run_hook(repo_cmd_runner, hook, file_args):
     return repo_cmd_runner.run(
-        ['xargs', hook['entry']] + hook.get('args', []),
+        ['xargs', hook['entry']] + hook['args'],
         # TODO: this is duplicated in pre_commit/languages/helpers.py
         stdin='\n'.join(list(file_args) + ['']),
         retcode=None,

pre_commit/repository.py

@@ -27,9 +27,7 @@ class Repository(object):
 
     @cached_property
     def languages(self):
-        return set(filter(None, (
-            hook.get('language') for hook in self.hooks.values()
-        )))
+        return set(hook['language'] for hook in self.hooks.values())
 
     @cached_property
     def hooks(self):

pre_commit/run.py

@@ -38,7 +38,7 @@ def _run_single_hook(runner, repository, hook_id, all_files=False):
         get_filenames(hook['files']),
     )
 
-    if retcode != repository.hooks[hook_id].get('expected_return_value', 0):
+    if retcode != repository.hooks[hook_id]['expected_return_value']:
         output = '\n'.join([stdout, stderr]).strip()
         retcode = 1
         color = RED