Added the useful thinking bit of the autoupdate and tests.

pre_commit/commands.py

@@ -4,6 +4,10 @@ from __future__ import print_function
 import os
 import pkg_resources
 import stat
+from plumbum import local
+
+from pre_commit.ordereddict import OrderedDict
+from pre_commit.repository import Repository
 
 
 def install(runner):
@@ -29,3 +33,46 @@ def uninstall(runner):
         os.remove(runner.pre_commit_path)
         print('pre-commit uninstalled')
     return 0
+
+
+class RepositoryCannotBeUpdatedError(RuntimeError): pass
+
+
+def _update_repository(repo_config):
+    """Updates a repository to the tip of `master`.  If the repository cannot
+    be updated because a hook that is configured does not exist in `master`,
+    this raises a RepositoryCannotBeUpdatedError
+
+    Args:
+        repo_config - A config for a repository
+    """
+    repo = Repository(repo_config)
+
+    with repo.in_checkout():
+        local['git']['fetch']()
+        head_sha = local['git']['rev-parse', 'origin/master']().strip()
+
+    # Don't bother trying to update if our sha is the same
+    if head_sha == repo_config['sha']:
+        return repo_config
+
+    # Construct a new config with the head sha
+    new_config = OrderedDict(repo_config)
+    new_config['sha'] = head_sha
+    new_repo = Repository(new_config)
+
+    # See if any of our hooks were deleted with the new commits
+    hooks = set(repo.hooks.keys())
+    hooks_missing = hooks - (hooks & set(new_repo.manifest.keys()))
+    if hooks_missing:
+        raise RepositoryCannotBeUpdatedError(
+            'Cannot update because the tip of master is missing these hooks:\n'
+            '{0}'.format(', '.join(sorted(hooks_missing)))
+        )
+
+    return new_config
+
+
+def autoupdate(runner):
+    """Auto-update the pre-commit config to the latest versions of repos."""
+    pass

pre_commit/run.py

@@ -100,14 +100,7 @@ def run(argv):
 
     subparsers.add_parser('uninstall', help='Uninstall the pre-commit script.')
 
-    execute_hook = subparsers.add_parser(
+    subparsers.add_parser('autoupdate', help='Auto-update hooks config.')
-        'execute-hook', help='Run a single hook.'
-    )
-    execute_hook.add_argument('hook', help='The hook-id to run.')
-    execute_hook.add_argument(
-        '--all-files', '-a', action='store_true', default=False,
-        help='Run on all the files in the repo.',
-    )
 
     run = subparsers.add_parser('run', help='Run hooks.')
     run.add_argument('hook', nargs='?', help='A single hook-id to run'),
@@ -130,6 +123,8 @@ def run(argv):
         return commands.install(runner)
     elif args.command == 'uninstall':
         return commands.uninstall(runner)
+    elif args.command == 'autoupdate':
+        return commands.autoupdate(runner)
     elif args.command == 'run':
         if args.hook:
             return run_single_hook(runner, args.hook, all_files=args.all_files)

testing/auto_namedtuple.py

@@ -0,0 +1,11 @@
+
+import collections
+
+def auto_namedtuple(classname='auto_namedtuple', **kwargs):
+    """Returns an automatic namedtuple object.
+
+    Args:
+        classname - The class name for the returned object.
+        **kwargs - Properties to give the returned object.
+    """
+    return (collections.namedtuple(classname, kwargs.keys())(**kwargs))

testing/resources/manifest_without_foo.yaml

@@ -0,0 +1,4 @@
+-   id: bar
+    name: Bar
+    entry: bar
+    language: python

tests/commands_test.py

@@ -1,12 +1,24 @@
 
+import jsonschema
 import os
 import os.path
 import pkg_resources
+import pytest
+import shutil
 import stat
+from plumbum import local
 
+from pre_commit import git
+from pre_commit.clientlib.validate_config import CONFIG_JSON_SCHEMA
+from pre_commit.clientlib.validate_config import validate_config_extra
 from pre_commit.commands import install
+from pre_commit.commands import RepositoryCannotBeUpdatedError
 from pre_commit.commands import uninstall
+from pre_commit.commands import _update_repository
+from pre_commit.ordereddict import OrderedDict
 from pre_commit.runner import Runner
+from testing.auto_namedtuple import auto_namedtuple
+from testing.util import get_resource_path
 
 
 def test_install_pre_commit(empty_git_dir):
@@ -35,3 +47,70 @@ def test_uninstall(empty_git_dir):
     assert os.path.exists(runner.pre_commit_path)
     uninstall(runner)
     assert not os.path.exists(runner.pre_commit_path)
+
+
+@pytest.yield_fixture
+def up_to_date_repo(python_hooks_repo):
+    config = OrderedDict((
+        ('repo', python_hooks_repo),
+        ('sha', git.get_head_sha(python_hooks_repo)),
+        ('hooks', [{'id': 'foo', 'files': ''}]),
+    ))
+    jsonschema.validate([config], CONFIG_JSON_SCHEMA)
+    validate_config_extra([config])
+    yield auto_namedtuple(
+        repo_config=config,
+        python_hooks_repo=python_hooks_repo,
+    )
+
+
+def test_up_to_date_repo(up_to_date_repo):
+    input_sha = up_to_date_repo.repo_config['sha']
+    ret = _update_repository(up_to_date_repo.repo_config)
+    assert ret['sha'] == input_sha
+
+
+@pytest.yield_fixture
+def out_of_date_repo(python_hooks_repo):
+    config = OrderedDict((
+        ('repo', python_hooks_repo),
+        ('sha', git.get_head_sha(python_hooks_repo)),
+        ('hooks', [{'id': 'foo', 'files': ''}]),
+    ))
+    jsonschema.validate([config], CONFIG_JSON_SCHEMA)
+    validate_config_extra([config])
+    local['git']['commit', '--allow-empty', '-m', 'foo']()
+    head_sha = git.get_head_sha(python_hooks_repo)
+    yield auto_namedtuple(
+        repo_config=config,
+        head_sha=head_sha,
+        python_hooks_repo=python_hooks_repo,
+    )
+
+
+def test_out_of_date_repo(out_of_date_repo):
+    ret = _update_repository(out_of_date_repo.repo_config)
+    assert ret['sha'] == out_of_date_repo.head_sha
+
+
+@pytest.yield_fixture
+def hook_disappearing_repo(python_hooks_repo):
+    config = OrderedDict((
+        ('repo', python_hooks_repo),
+        ('sha', git.get_head_sha(python_hooks_repo)),
+        ('hooks', [{'id': 'foo', 'files': ''}]),
+    ))
+    jsonschema.validate([config], CONFIG_JSON_SCHEMA)
+    validate_config_extra([config])
+    shutil.copy(get_resource_path('manifest_without_foo.yaml'), 'manifest.yaml')
+    local['git']['add', '.']()
+    local['git']['commit', '-m', 'Remove foo']()
+    yield auto_namedtuple(
+        repo_config=config,
+        python_hooks_repo=python_hooks_repo,
+    )
+
+
+def test_hook_disppearing_repo_raises(hook_disappearing_repo):
+    with pytest.raises(RepositoryCannotBeUpdatedError):
+        _update_repository(hook_disappearing_repo.repo_config)