Teach pre-commit try-repo to clone uncommitted changes

pre_commit/commands/run.py

@@ -199,11 +199,7 @@ def _run_hooks(config, hooks, args, environ):
         retval |= _run_single_hook(filenames, hook, args, skips, cols)
         if retval and config['fail_fast']:
             break
-    if (
-            retval and
-            args.show_diff_on_failure and
-            subprocess.call(('git', 'diff', '--quiet', '--no-ext-diff')) != 0
-    ):
+    if retval and args.show_diff_on_failure and git.has_diff():
         output.write_line('All changes made by hooks:')
         subprocess.call(('git', '--no-pager', 'diff', '--no-ext-diff'))
     return retval

pre_commit/commands/try_repo.py

@@ -2,6 +2,7 @@ from __future__ import absolute_import
 from __future__ import unicode_literals
 
 import collections
+import logging
 import os.path
 
 from aspy.yaml import ordered_dump
@@ -12,23 +13,50 @@ from pre_commit import output
 from pre_commit.clientlib import load_manifest
 from pre_commit.commands.run import run
 from pre_commit.store import Store
+from pre_commit.util import cmd_output
 from pre_commit.util import tmpdir
 
+logger = logging.getLogger(__name__)
+
+
+def _repo_ref(tmpdir, repo, ref):
+    # if `ref` is explicitly passed, use it
+    if ref:
+        return repo, ref
+
+    ref = git.head_rev(repo)
+    # if it exists on disk, we'll try and clone it with the local changes
+    if os.path.exists(repo) and git.has_diff('HEAD', repo=repo):
+        logger.warning('Creating temporary repo with uncommitted changes...')
+
+        shadow = os.path.join(tmpdir, 'shadow-repo')
+        cmd_output('git', 'clone', repo, shadow)
+        cmd_output('git', 'checkout', ref, '-b', '_pc_tmp', cwd=shadow)
+        idx = git.git_path('index', repo=shadow)
+        objs = git.git_path('objects', repo=shadow)
+        env = dict(os.environ, GIT_INDEX_FILE=idx, GIT_OBJECT_DIRECTORY=objs)
+        cmd_output('git', 'add', '-u', cwd=repo, env=env)
+        git.commit(repo=shadow)
+
+        return shadow, git.head_rev(shadow)
+    else:
+        return repo, ref
+
 
 def try_repo(args):
-    ref = args.ref or git.head_rev(args.repo)
-
     with tmpdir() as tempdir:
+        repo, ref = _repo_ref(tempdir, args.repo, args.ref)
+
         store = Store(tempdir)
         if args.hook:
             hooks = [{'id': args.hook}]
         else:
-            repo_path = store.clone(args.repo, ref)
+            repo_path = store.clone(repo, ref)
             manifest = load_manifest(os.path.join(repo_path, C.MANIFEST_FILE))
             manifest = sorted(manifest, key=lambda hook: hook['id'])
             hooks = [{'id': hook['id']} for hook in manifest]
 
-        items = (('repo', args.repo), ('rev', ref), ('hooks', hooks))
+        items = (('repo', repo), ('rev', ref), ('hooks', hooks))
         config = {'repos': [collections.OrderedDict(items)]}
         config_s = ordered_dump(config, **C.YAML_DUMP_KWARGS)
 

pre_commit/git.py

@@ -4,12 +4,10 @@ import logging
 import os.path
 import sys
 
-from pre_commit.error_handler import FatalError
-from pre_commit.util import CalledProcessError
 from pre_commit.util import cmd_output
 
 
-logger = logging.getLogger('pre_commit')
+logger = logging.getLogger(__name__)
 
 
 def zsplit(s):
@@ -20,14 +18,23 @@ def zsplit(s):
         return []
 
 
+def no_git_env():
+    # Too many bugs dealing with environment variables and GIT:
+    # https://github.com/pre-commit/pre-commit/issues/300
+    # In git 2.6.3 (maybe others), git exports GIT_WORK_TREE while running
+    # pre-commit hooks
+    # In git 1.9.1 (maybe others), git exports GIT_DIR and GIT_INDEX_FILE
+    # while running pre-commit hooks in submodules.
+    # GIT_DIR: Causes git clone to clone wrong thing
+    # GIT_INDEX_FILE: Causes 'error invalid object ...' during commit
+    return {
+        k: v for k, v in os.environ.items()
+        if not k.startswith('GIT_') or k in {'GIT_SSH'}
+    }
+
+
 def get_root():
-    try:
-        return cmd_output('git', 'rev-parse', '--show-toplevel')[1].strip()
-    except CalledProcessError:
-        raise FatalError(
-            'git failed. Is it installed, and are you in a Git repository '
-            'directory?',
-        )
+    return cmd_output('git', 'rev-parse', '--show-toplevel')[1].strip()
 
 
 def get_git_dir(git_root='.'):
@@ -106,6 +113,27 @@ def head_rev(remote):
     return out.split()[0]
 
 
+def has_diff(*args, **kwargs):
+    repo = kwargs.pop('repo', '.')
+    assert not kwargs, kwargs
+    cmd = ('git', 'diff', '--quiet', '--no-ext-diff') + args
+    return cmd_output(*cmd, cwd=repo, retcode=None)[0]
+
+
+def commit(repo='.'):
+    env = no_git_env()
+    name, email = 'pre-commit', 'asottile+pre-commit@umich.edu'
+    env['GIT_AUTHOR_NAME'] = env['GIT_COMMITTER_NAME'] = name
+    env['GIT_AUTHOR_EMAIL'] = env['GIT_COMMITTER_EMAIL'] = email
+    cmd = ('git', 'commit', '--no-edit', '--no-gpg-sign', '-n', '-minit')
+    cmd_output(*cmd, cwd=repo, env=env)
+
+
+def git_path(name, repo='.'):
+    _, out, _ = cmd_output('git', 'rev-parse', '--git-path', name, cwd=repo)
+    return os.path.join(repo, out.strip())
+
+
 def check_for_cygwin_mismatch():
     """See https://github.com/pre-commit/pre-commit/issues/354"""
     if sys.platform in ('cygwin', 'win32'):  # pragma: no cover (windows)

pre_commit/main.py

@@ -19,8 +19,10 @@ from pre_commit.commands.run import run
 from pre_commit.commands.sample_config import sample_config
 from pre_commit.commands.try_repo import try_repo
 from pre_commit.error_handler import error_handler
+from pre_commit.error_handler import FatalError
 from pre_commit.logging_handler import add_logging_handler
 from pre_commit.store import Store
+from pre_commit.util import CalledProcessError
 
 
 logger = logging.getLogger('pre_commit')
@@ -97,7 +99,13 @@ def _adjust_args_and_chdir(args):
     if args.command == 'try-repo' and os.path.exists(args.repo):
         args.repo = os.path.abspath(args.repo)
 
-    os.chdir(git.get_root())
+    try:
+        os.chdir(git.get_root())
+    except CalledProcessError:
+        raise FatalError(
+            'git failed. Is it installed, and are you in a Git repository '
+            'directory?',
+        )
 
     args.config = os.path.relpath(args.config)
     if args.command in {'run', 'try-repo'}:

pre_commit/store.py

@@ -9,9 +9,9 @@ import tempfile
 
 import pre_commit.constants as C
 from pre_commit import file_lock
+from pre_commit import git
 from pre_commit.util import clean_path_on_failure
 from pre_commit.util import cmd_output
-from pre_commit.util import no_git_env
 from pre_commit.util import resource_text
 
 
@@ -135,7 +135,7 @@ class Store(object):
     def clone(self, repo, ref, deps=()):
         """Clone the given url and checkout the specific ref."""
         def clone_strategy(directory):
-            env = no_git_env()
+            env = git.no_git_env()
 
             cmd = ('git', 'clone', '--no-checkout', repo, directory)
             cmd_output(*cmd, env=env)
@@ -160,10 +160,7 @@ class Store(object):
                 with io.open(os.path.join(directory, resource), 'w') as f:
                     f.write(contents)
 
-            env = no_git_env()
-            name, email = 'pre-commit', 'asottile+pre-commit@umich.edu'
-            env['GIT_AUTHOR_NAME'] = env['GIT_COMMITTER_NAME'] = name
-            env['GIT_AUTHOR_EMAIL'] = env['GIT_COMMITTER_EMAIL'] = email
+            env = git.no_git_env()
 
             # initialize the git repository so it looks more like cloned repos
             def _git_cmd(*args):
@@ -172,7 +169,7 @@ class Store(object):
             _git_cmd('init', '.')
             _git_cmd('config', 'remote.origin.url', '<<unknown>>')
             _git_cmd('add', '.')
-            _git_cmd('commit', '--no-edit', '--no-gpg-sign', '-n', '-minit')
+            git.commit(repo=directory)
 
         return self._new_repo(
             'local', C.LOCAL_REPO_VERSION, deps, make_local_strategy,

pre_commit/util.py

@@ -64,21 +64,6 @@ def noop_context():
     yield
 
 
-def no_git_env():
-    # Too many bugs dealing with environment variables and GIT:
-    # https://github.com/pre-commit/pre-commit/issues/300
-    # In git 2.6.3 (maybe others), git exports GIT_WORK_TREE while running
-    # pre-commit hooks
-    # In git 1.9.1 (maybe others), git exports GIT_DIR and GIT_INDEX_FILE
-    # while running pre-commit hooks in submodules.
-    # GIT_DIR: Causes git clone to clone wrong thing
-    # GIT_INDEX_FILE: Causes 'error invalid object ...' during commit
-    return {
-        k: v for k, v in os.environ.items()
-        if not k.startswith('GIT_') or k in {'GIT_SSH'}
-    }
-
-
 @contextlib.contextmanager
 def tmpdir():
     """Contextmanager to create a temporary directory.  It will be cleaned up