Adding upstream version 2.2.0.upstream/2.2.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 1198 insertions, 0 deletions

diff --git a/pre_commit/commands/__init__.py b/pre_commit/commands/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/pre_commit/commands/__init__.py
diff --git a/pre_commit/commands/autoupdate.py b/pre_commit/commands/autoupdate.py
new file mode 100644
index 0000000..5a9a988
--- /dev/null
+++ b/pre_commit/commands/autoupdate.py
@@ -0,0 +1,182 @@
+import os.path
+import re
+from typing import Any
+from typing import Dict
+from typing import List
+from typing import NamedTuple
+from typing import Optional
+from typing import Sequence
+from typing import Tuple
+
+import pre_commit.constants as C
+from pre_commit import git
+from pre_commit import output
+from pre_commit.clientlib import InvalidManifestError
+from pre_commit.clientlib import load_config
+from pre_commit.clientlib import load_manifest
+from pre_commit.clientlib import LOCAL
+from pre_commit.clientlib import META
+from pre_commit.commands.migrate_config import migrate_config
+from pre_commit.store import Store
+from pre_commit.util import CalledProcessError
+from pre_commit.util import cmd_output
+from pre_commit.util import cmd_output_b
+from pre_commit.util import tmpdir
+from pre_commit.util import yaml_dump
+from pre_commit.util import yaml_load
+
+
+class RevInfo(NamedTuple):
+    repo: str
+    rev: str
+    frozen: Optional[str]
+
+    @classmethod
+    def from_config(cls, config: Dict[str, Any]) -> 'RevInfo':
+        return cls(config['repo'], config['rev'], None)
+
+    def update(self, tags_only: bool, freeze: bool) -> 'RevInfo':
+        if tags_only:
+            tag_cmd = ('git', 'describe', 'FETCH_HEAD', '--tags', '--abbrev=0')
+        else:
+            tag_cmd = ('git', 'describe', 'FETCH_HEAD', '--tags', '--exact')
+
+        with tmpdir() as tmp:
+            git.init_repo(tmp, self.repo)
+            cmd_output_b('git', 'fetch', 'origin', 'HEAD', '--tags', cwd=tmp)
+
+            try:
+                rev = cmd_output(*tag_cmd, cwd=tmp)[1].strip()
+            except CalledProcessError:
+                cmd = ('git', 'rev-parse', 'FETCH_HEAD')
+                rev = cmd_output(*cmd, cwd=tmp)[1].strip()
+
+            frozen = None
+            if freeze:
+                exact = cmd_output('git', 'rev-parse', rev, cwd=tmp)[1].strip()
+                if exact != rev:
+                    rev, frozen = exact, rev
+        return self._replace(rev=rev, frozen=frozen)
+
+
+class RepositoryCannotBeUpdatedError(RuntimeError):
+    pass
+
+
+def _check_hooks_still_exist_at_rev(
+        repo_config: Dict[str, Any],
+        info: RevInfo,
+        store: Store,
+) -> None:
+    try:
+        path = store.clone(repo_config['repo'], info.rev)
+        manifest = load_manifest(os.path.join(path, C.MANIFEST_FILE))
+    except InvalidManifestError as e:
+        raise RepositoryCannotBeUpdatedError(str(e))
+
+    # See if any of our hooks were deleted with the new commits
+    hooks = {hook['id'] for hook in repo_config['hooks']}
+    hooks_missing = hooks - {hook['id'] for hook in manifest}
+    if hooks_missing:
+        raise RepositoryCannotBeUpdatedError(
+            f'Cannot update because the tip of HEAD is missing these hooks:\n'
+            f'{", ".join(sorted(hooks_missing))}',
+        )
+
+
+REV_LINE_RE = re.compile(r'^(\s+)rev:(\s*)([^\s#]+)(.*)(\r?\n)$', re.DOTALL)
+
+
+def _original_lines(
+        path: str,
+        rev_infos: List[Optional[RevInfo]],
+        retry: bool = False,
+) -> Tuple[List[str], List[int]]:
+    """detect `rev:` lines or reformat the file"""
+    with open(path) as f:
+        original = f.read()
+
+    lines = original.splitlines(True)
+    idxs = [i for i, line in enumerate(lines) if REV_LINE_RE.match(line)]
+    if len(idxs) == len(rev_infos):
+        return lines, idxs
+    elif retry:
+        raise AssertionError('could not find rev lines')
+    else:
+        with open(path, 'w') as f:
+            f.write(yaml_dump(yaml_load(original)))
+        return _original_lines(path, rev_infos, retry=True)
+
+
+def _write_new_config(path: str, rev_infos: List[Optional[RevInfo]]) -> None:
+    lines, idxs = _original_lines(path, rev_infos)
+
+    for idx, rev_info in zip(idxs, rev_infos):
+        if rev_info is None:
+            continue
+        match = REV_LINE_RE.match(lines[idx])
+        assert match is not None
+        new_rev_s = yaml_dump({'rev': rev_info.rev})
+        new_rev = new_rev_s.split(':', 1)[1].strip()
+        if rev_info.frozen is not None:
+            comment = f'  # frozen: {rev_info.frozen}'
+        elif match[4].strip().startswith('# frozen:'):
+            comment = ''
+        else:
+            comment = match[4]
+        lines[idx] = f'{match[1]}rev:{match[2]}{new_rev}{comment}{match[5]}'
+
+    with open(path, 'w') as f:
+        f.write(''.join(lines))
+
+
+def autoupdate(
+        config_file: str,
+        store: Store,
+        tags_only: bool,
+        freeze: bool,
+        repos: Sequence[str] = (),
+) -> int:
+    """Auto-update the pre-commit config to the latest versions of repos."""
+    migrate_config(config_file, quiet=True)
+    retv = 0
+    rev_infos: List[Optional[RevInfo]] = []
+    changed = False
+
+    config = load_config(config_file)
+    for repo_config in config['repos']:
+        if repo_config['repo'] in {LOCAL, META}:
+            continue
+
+        info = RevInfo.from_config(repo_config)
+        if repos and info.repo not in repos:
+            rev_infos.append(None)
+            continue
+
+        output.write(f'Updating {info.repo} ... ')
+        new_info = info.update(tags_only=tags_only, freeze=freeze)
+        try:
+            _check_hooks_still_exist_at_rev(repo_config, new_info, store)
+        except RepositoryCannotBeUpdatedError as error:
+            output.write_line(error.args[0])
+            rev_infos.append(None)
+            retv = 1
+            continue
+
+        if new_info.rev != info.rev:
+            changed = True
+            if new_info.frozen:
+                updated_to = f'{new_info.frozen} (frozen)'
+            else:
+                updated_to = new_info.rev
+            msg = f'updating {info.rev} -> {updated_to}.'
+            output.write_line(msg)
+            rev_infos.append(new_info)
+        else:
+            output.write_line('already up to date.')
+            rev_infos.append(None)
+
+    if changed:
+        _write_new_config(config_file, rev_infos)
+
+    return retv
diff --git a/pre_commit/commands/clean.py b/pre_commit/commands/clean.py
new file mode 100644
index 0000000..2be6c16
--- /dev/null
+++ b/pre_commit/commands/clean.py
@@ -0,0 +1,14 @@
+import os.path
+
+from pre_commit import output
+from pre_commit.store import Store
+from pre_commit.util import rmtree
+
+
+def clean(store: Store) -> int:
+    legacy_path = os.path.expanduser('~/.pre-commit')
+    for directory in (store.directory, legacy_path):
+        if os.path.exists(directory):
+            rmtree(directory)
+            output.write_line(f'Cleaned {directory}.')
+    return 0
diff --git a/pre_commit/commands/gc.py b/pre_commit/commands/gc.py
new file mode 100644
index 0000000..7f6d311
--- /dev/null
+++ b/pre_commit/commands/gc.py
@@ -0,0 +1,90 @@
+import os.path
+from typing import Any
+from typing import Dict
+from typing import Set
+from typing import Tuple
+
+import pre_commit.constants as C
+from pre_commit import output
+from pre_commit.clientlib import InvalidConfigError
+from pre_commit.clientlib import InvalidManifestError
+from pre_commit.clientlib import load_config
+from pre_commit.clientlib import load_manifest
+from pre_commit.clientlib import LOCAL
+from pre_commit.clientlib import META
+from pre_commit.store import Store
+
+
+def _mark_used_repos(
+        store: Store,
+        all_repos: Dict[Tuple[str, str], str],
+        unused_repos: Set[Tuple[str, str]],
+        repo: Dict[str, Any],
+) -> None:
+    if repo['repo'] == META:
+        return
+    elif repo['repo'] == LOCAL:
+        for hook in repo['hooks']:
+            deps = hook.get('additional_dependencies')
+            unused_repos.discard((
+                store.db_repo_name(repo['repo'], deps), C.LOCAL_REPO_VERSION,
+            ))
+    else:
+        key = (repo['repo'], repo['rev'])
+        path = all_repos.get(key)
+        # can't inspect manifest if it isn't cloned
+        if path is None:
+            return
+
+        try:
+            manifest = load_manifest(os.path.join(path, C.MANIFEST_FILE))
+        except InvalidManifestError:
+            return
+        else:
+            unused_repos.discard(key)
+            by_id = {hook['id']: hook for hook in manifest}
+
+        for hook in repo['hooks']:
+            if hook['id'] not in by_id:
+                continue
+
+            deps = hook.get(
+                'additional_dependencies',
+                by_id[hook['id']]['additional_dependencies'],
+            )
+            unused_repos.discard((
+                store.db_repo_name(repo['repo'], deps), repo['rev'],
+            ))
+
+
+def _gc_repos(store: Store) -> int:
+    configs = store.select_all_configs()
+    repos = store.select_all_repos()
+
+    # delete config paths which do not exist
+    dead_configs = [p for p in configs if not os.path.exists(p)]
+    live_configs = [p for p in configs if os.path.exists(p)]
+
+    all_repos = {(repo, ref): path for repo, ref, path in repos}
+    unused_repos = set(all_repos)
+    for config_path in live_configs:
+        try:
+            config = load_config(config_path)
+        except InvalidConfigError:
+            dead_configs.append(config_path)
+            continue
+        else:
+            for repo in config['repos']:
+                _mark_used_repos(store, all_repos, unused_repos, repo)
+
+    store.delete_configs(dead_configs)
+    for db_repo_name, ref in unused_repos:
+        store.delete_repo(db_repo_name, ref, all_repos[(db_repo_name, ref)])
+    return len(unused_repos)
+
+
+def gc(store: Store) -> int:
+    with store.exclusive_lock():
+        repos_removed = _gc_repos(store)
+    output.write_line(f'{repos_removed} repo(s) removed.')
+    return 0
diff --git a/pre_commit/commands/hook_impl.py b/pre_commit/commands/hook_impl.py
new file mode 100644
index 0000000..5ff4555
--- /dev/null
+++ b/pre_commit/commands/hook_impl.py
@@ -0,0 +1,187 @@
+import argparse
+import os.path
+import subprocess
+import sys
+from typing import Optional
+from typing import Sequence
+from typing import Tuple
+
+from pre_commit.commands.run import run
+from pre_commit.envcontext import envcontext
+from pre_commit.parse_shebang import normalize_cmd
+from pre_commit.store import Store
+
+Z40 = '0' * 40
+
+
+def _run_legacy(
+        hook_type: str,
+        hook_dir: str,
+        args: Sequence[str],
+) -> Tuple[int, bytes]:
+    if os.environ.get('PRE_COMMIT_RUNNING_LEGACY'):
+        raise SystemExit(
+            f"bug: pre-commit's script is installed in migration mode\n"
+            f'run `pre-commit install -f --hook-type {hook_type}` to fix '
+            f'this\n\n'
+            f'Please report this bug at '
+            f'https://github.com/pre-commit/pre-commit/issues',
+        )
+
+    if hook_type == 'pre-push':
+        stdin = sys.stdin.buffer.read()
+    else:
+        stdin = b''
+
+    # not running in legacy mode
+    legacy_hook = os.path.join(hook_dir, f'{hook_type}.legacy')
+    if not os.access(legacy_hook, os.X_OK):
+        return 0, stdin
+
+    with envcontext((('PRE_COMMIT_RUNNING_LEGACY', '1'),)):
+        cmd = normalize_cmd((legacy_hook, *args))
+        return subprocess.run(cmd, input=stdin).returncode, stdin
+
+
+def _validate_config(
+        retv: int,
+        config: str,
+        skip_on_missing_config: bool,
+) -> None:
+    if not os.path.isfile(config):
+        if skip_on_missing_config or os.getenv('PRE_COMMIT_ALLOW_NO_CONFIG'):
+            print(f'`{config}` config file not found. Skipping `pre-commit`.')
+            raise SystemExit(retv)
+        else:
+            print(
+                f'No {config} file was found\n'
+                f'- To temporarily silence this, run '
+                f'`PRE_COMMIT_ALLOW_NO_CONFIG=1 git ...`\n'
+                f'- To permanently silence this, install pre-commit with the '
+                f'--allow-missing-config option\n'
+                f'- To uninstall pre-commit run `pre-commit uninstall`',
+            )
+            raise SystemExit(1)
+
+
+def _ns(
+        hook_type: str,
+        color: bool,
+        *,
+        all_files: bool = False,
+        from_ref: Optional[str] = None,
+        to_ref: Optional[str] = None,
+        remote_name: Optional[str] = None,
+        remote_url: Optional[str] = None,
+        commit_msg_filename: Optional[str] = None,
+        checkout_type: Optional[str] = None,
+) -> argparse.Namespace:
+    return argparse.Namespace(
+        color=color,
+        hook_stage=hook_type.replace('pre-', ''),
+        from_ref=from_ref,
+        to_ref=to_ref,
+        remote_name=remote_name,
+        remote_url=remote_url,
+        commit_msg_filename=commit_msg_filename,
+        all_files=all_files,
+        checkout_type=checkout_type,
+        files=(),
+        hook=None,
+        verbose=False,
+        show_diff_on_failure=False,
+    )
+
+
+def _rev_exists(rev: str) -> bool:
+    return not subprocess.call(('git', 'rev-list', '--quiet', rev))
+
+
+def _pre_push_ns(
+        color: bool,
+        args: Sequence[str],
+        stdin: bytes,
+) -> Optional[argparse.Namespace]:
+    remote_name = args[0]
+    remote_url = args[1]
+
+    for line in stdin.decode().splitlines():
+        _, local_sha, _, remote_sha = line.split()
+        if local_sha == Z40:
+            continue
+        elif remote_sha != Z40 and _rev_exists(remote_sha):
+            return _ns(
+                'pre-push', color,
+                from_ref=remote_sha, to_ref=local_sha,
+                remote_name=remote_name, remote_url=remote_url,
+            )
+        else:
+            # ancestors not found in remote
+            ancestors = subprocess.check_output((
+                'git', 'rev-list', local_sha, '--topo-order', '--reverse',
+                '--not', f'--remotes={remote_name}',
+            )).decode().strip()
+            if not ancestors:
+                continue
+            else:
+                first_ancestor = ancestors.splitlines()[0]
+                cmd = ('git', 'rev-list', '--max-parents=0', local_sha)
+                roots = set(subprocess.check_output(cmd).decode().splitlines())
+                if first_ancestor in roots:
+                    # pushing the whole tree including root commit
+                    return _ns(
+                        'pre-push', color,
+                        all_files=True,
+                        remote_name=remote_name, remote_url=remote_url,
+                    )
+                else:
+                    rev_cmd = ('git', 'rev-parse', f'{first_ancestor}^')
+                    source = subprocess.check_output(rev_cmd).decode().strip()
+                    return _ns(
+                        'pre-push', color,
+                        from_ref=source, to_ref=local_sha,
+                        remote_name=remote_name, remote_url=remote_url,
+                    )
+
+    # nothing to push
+    return None
+
+
+def _run_ns(
+        hook_type: str,
+        color: bool,
+        args: Sequence[str],
+        stdin: bytes,
+) -> Optional[argparse.Namespace]:
+    if hook_type == 'pre-push':
+        return _pre_push_ns(color, args, stdin)
+    elif hook_type in {'prepare-commit-msg', 'commit-msg'}:
+        return _ns(hook_type, color, commit_msg_filename=args[0])
+    elif hook_type in {'pre-merge-commit', 'pre-commit'}:
+        return _ns(hook_type, color)
+    elif hook_type == 'post-checkout':
+        return _ns(
+            hook_type, color,
+            from_ref=args[0], to_ref=args[1], checkout_type=args[2],
+        )
+    else:
+        raise AssertionError(f'unexpected hook type: {hook_type}')
+
+
+def hook_impl(
+        store: Store,
+        *,
+        config: str,
+        color: bool,
+        hook_type: str,
+        hook_dir: str,
+        skip_on_missing_config: bool,
+        args: Sequence[str],
+) -> int:
+    retv, stdin = _run_legacy(hook_type, hook_dir, args)
+    _validate_config(retv, config, skip_on_missing_config)
+    ns = _run_ns(hook_type, color, args, stdin)
+    if ns is None:
+        return retv
+    else:
+        return retv | run(config, store, ns)
diff --git a/pre_commit/commands/init_templatedir.py b/pre_commit/commands/init_templatedir.py
new file mode 100644
index 0000000..f676fb1
--- /dev/null
+++ b/pre_commit/commands/init_templatedir.py
@@ -0,0 +1,33 @@
+import logging
+import os.path
+from typing import Sequence
+
+from pre_commit.commands.install_uninstall import install
+from pre_commit.store import Store
+from pre_commit.util import CalledProcessError
+from pre_commit.util import cmd_output
+
+logger = logging.getLogger('pre_commit')
+
+
+def init_templatedir(
+        config_file: str,
+        store: Store,
+        directory: str,
+        hook_types: Sequence[str],
+) -> int:
+    install(
+        config_file, store, hook_types=hook_types,
+        overwrite=True, skip_on_missing_config=True, git_dir=directory,
+    )
+    try:
+        _, out, _ = cmd_output('git', 'config', 'init.templateDir')
+    except CalledProcessError:
+        configured_path = None
+    else:
+        configured_path = os.path.realpath(os.path.expanduser(out.strip()))
+    dest = os.path.realpath(directory)
+    if configured_path != dest:
+        logger.warning('`init.templateDir` not set to the target directory')
+        logger.warning(f'maybe `git config --global init.templateDir {dest}`?')
+    return 0
diff --git a/pre_commit/commands/install_uninstall.py b/pre_commit/commands/install_uninstall.py
new file mode 100644
index 0000000..c8b7633
--- /dev/null
+++ b/pre_commit/commands/install_uninstall.py
@@ -0,0 +1,175 @@
+import itertools
+import logging
+import os.path
+import shutil
+import sys
+from typing import Optional
+from typing import Sequence
+from typing import Tuple
+
+from pre_commit import git
+from pre_commit import output
+from pre_commit.clientlib import load_config
+from pre_commit.repository import all_hooks
+from pre_commit.repository import install_hook_envs
+from pre_commit.store import Store
+from pre_commit.util import make_executable
+from pre_commit.util import resource_text
+
+
+logger = logging.getLogger(__name__)
+
+# This is used to identify the hook file we install
+PRIOR_HASHES = (
+    '4d9958c90bc262f47553e2c073f14cfe',
+    'd8ee923c46731b42cd95cc869add4062',
+    '49fd668cb42069aa1b6048464be5d395',
+    '79f09a650522a87b0da915d0d983b2de',
+    'e358c9dae00eac5d06b38dfdb1e33a8c',
+)
+CURRENT_HASH = '138fd403232d2ddd5efb44317e38bf03'
+TEMPLATE_START = '# start templated\n'
+TEMPLATE_END = '# end templated\n'
+# Homebrew/homebrew-core#35825: be more timid about appropriate `PATH`
+# #1312 os.defpath is too restrictive on BSD
+POSIX_SEARCH_PATH = ('/usr/local/bin', '/usr/bin', '/bin')
+SYS_EXE = os.path.basename(os.path.realpath(sys.executable))
+
+
+def _hook_paths(
+        hook_type: str,
+        git_dir: Optional[str] = None,
+) -> Tuple[str, str]:
+    git_dir = git_dir if git_dir is not None else git.get_git_dir()
+    pth = os.path.join(git_dir, 'hooks', hook_type)
+    return pth, f'{pth}.legacy'
+
+
+def is_our_script(filename: str) -> bool:
+    if not os.path.exists(filename):  # pragma: win32 no cover (symlink)
+        return False
+    with open(filename) as f:
+        contents = f.read()
+    return any(h in contents for h in (CURRENT_HASH,) + PRIOR_HASHES)
+
+
+def shebang() -> str:
+    if sys.platform == 'win32':
+        py = SYS_EXE
+    else:
+        exe_choices = [
+            f'python{sys.version_info[0]}.{sys.version_info[1]}',
+            f'python{sys.version_info[0]}',
+        ]
+        # avoid searching for bare `python` as it's likely to be python 2
+        if SYS_EXE != 'python':
+            exe_choices.append(SYS_EXE)
+        for path, exe in itertools.product(POSIX_SEARCH_PATH, exe_choices):
+            if os.access(os.path.join(path, exe), os.X_OK):
+                py = exe
+                break
+        else:
+            py = SYS_EXE
+    return f'#!/usr/bin/env {py}'
+
+
+def _install_hook_script(
+        config_file: str,
+        hook_type: str,
+        overwrite: bool = False,
+        skip_on_missing_config: bool = False,
+        git_dir: Optional[str] = None,
+) -> None:
+    hook_path, legacy_path = _hook_paths(hook_type, git_dir=git_dir)
+
+    os.makedirs(os.path.dirname(hook_path), exist_ok=True)
+
+    # If we have an existing hook, move it to pre-commit.legacy
+    if os.path.lexists(hook_path) and not is_our_script(hook_path):
+        shutil.move(hook_path, legacy_path)
+
+    # If we specify overwrite, we simply delete the legacy file
+    if overwrite and os.path.exists(legacy_path):
+        os.remove(legacy_path)
+    elif os.path.exists(legacy_path):
+        output.write_line(
+            f'Running in migration mode with existing hooks at {legacy_path}\n'
+            f'Use -f to use only pre-commit.',
+        )
+
+    args = ['hook-impl', f'--config={config_file}', f'--hook-type={hook_type}']
+    if skip_on_missing_config:
+        args.append('--skip-on-missing-config')
+    params = {'INSTALL_PYTHON': sys.executable, 'ARGS': args}
+
+    with open(hook_path, 'w') as hook_file:
+        contents = resource_text('hook-tmpl')
+        before, rest = contents.split(TEMPLATE_START)
+        to_template, after = rest.split(TEMPLATE_END)
+
+        before = before.replace('#!/usr/bin/env python3', shebang())
+
+        hook_file.write(before + TEMPLATE_START)
+        for line in to_template.splitlines():
+            var = line.split()[0]
+            hook_file.write(f'{var} = {params[var]!r}\n')
+        hook_file.write(TEMPLATE_END + after)
+    make_executable(hook_path)
+
+    output.write_line(f'pre-commit installed at {hook_path}')
+
+
+def install(
+        config_file: str,
+        store: Store,
+        hook_types: Sequence[str],
+        overwrite: bool = False,
+        hooks: bool = False,
+        skip_on_missing_config: bool = False,
+        git_dir: Optional[str] = None,
+) -> int:
+    if git_dir is None and git.has_core_hookpaths_set():
+        logger.error(
+            'Cowardly refusing to install hooks with `core.hooksPath` set.\n'
+            'hint: `git config --unset-all core.hooksPath`',
+        )
+        return 1
+
+    for hook_type in hook_types:
+        _install_hook_script(
+            config_file, hook_type,
+            overwrite=overwrite,
+            skip_on_missing_config=skip_on_missing_config,
+            git_dir=git_dir,
+        )
+
+    if hooks:
+        install_hooks(config_file, store)
+
+    return 0
+
+
+def install_hooks(config_file: str, store: Store) -> int:
+    install_hook_envs(all_hooks(load_config(config_file), store), store)
+    return 0
+
+
+def _uninstall_hook_script(hook_type: str) -> None:
+    hook_path, legacy_path = _hook_paths(hook_type)
+
+    # If our file doesn't exist or it isn't ours, gtfo.
+    if not os.path.exists(hook_path) or not is_our_script(hook_path):
+        return
+
+    os.remove(hook_path)
+    output.write_line(f'{hook_type} uninstalled')
+
+    if os.path.exists(legacy_path):
+        os.rename(legacy_path, hook_path)
+        output.write_line(f'Restored previous hooks to {hook_path}')
+
+
+def uninstall(hook_types: Sequence[str]) -> int:
+    for hook_type in hook_types:
+        _uninstall_hook_script(hook_type)
+    return 0
diff --git a/pre_commit/commands/migrate_config.py b/pre_commit/commands/migrate_config.py
new file mode 100644
index 0000000..d83b8e9
--- /dev/null
+++ b/pre_commit/commands/migrate_config.py
@@ -0,0 +1,59 @@
+import re
+
+import yaml
+
+from pre_commit.util import yaml_load
+
+
+def _indent(s: str) -> str:
+    lines = s.splitlines(True)
+    return ''.join(' ' * 4 + line if line.strip() else line for line in lines)
+
+
+def _is_header_line(line: str) -> bool:
+    return line.startswith(('#', '---')) or not line.strip()
+
+
+def _migrate_map(contents: str) -> str:
+    # Find the first non-header line
+    lines = contents.splitlines(True)
+    i = 0
+    # Only loop on non empty configuration file
+    while i < len(lines) and _is_header_line(lines[i]):
+        i += 1
+
+    header = ''.join(lines[:i])
+    rest = ''.join(lines[i:])
+
+    if isinstance(yaml_load(contents), list):
+        # If they are using the "default" flow style of yaml, this operation
+        # will yield a valid configuration
+        try:
+            trial_contents = f'{header}repos:\n{rest}'
+            yaml_load(trial_contents)
+            contents = trial_contents
+        except yaml.YAMLError:
+            contents = f'{header}repos:\n{_indent(rest)}'
+
+    return contents
+
+
+def _migrate_sha_to_rev(contents: str) -> str:
+    return re.sub(r'(\n\s+)sha:', r'\1rev:', contents)
+
+
+def migrate_config(config_file: str, quiet: bool = False) -> int:
+    with open(config_file) as f:
+        orig_contents = contents = f.read()
+
+    contents = _migrate_map(contents)
+    contents = _migrate_sha_to_rev(contents)
+
+    if contents != orig_contents:
+        with open(config_file, 'w') as f:
+            f.write(contents)
+
+        print('Configuration has been migrated.')
+    elif not quiet:
+        print('Configuration is already migrated.')
+    return 0
diff --git a/pre_commit/commands/run.py b/pre_commit/commands/run.py
new file mode 100644
index 0000000..2f74578
--- /dev/null
+++ b/pre_commit/commands/run.py
@@ -0,0 +1,360 @@
+import argparse
+import contextlib
+import functools
+import logging
+import os
+import re
+import subprocess
+import time
+from typing import Any
+from typing import Collection
+from typing import Dict
+from typing import List
+from typing import Sequence
+from typing import Set
+from typing import Tuple
+
+from identify.identify import tags_from_path
+
+from pre_commit import color
+from pre_commit import git
+from pre_commit import output
+from pre_commit.clientlib import load_config
+from pre_commit.hook import Hook
+from pre_commit.languages.all import languages
+from pre_commit.repository import all_hooks
+from pre_commit.repository import install_hook_envs
+from pre_commit.staged_files_only import staged_files_only
+from pre_commit.store import Store
+from pre_commit.util import cmd_output_b
+from pre_commit.util import EnvironT
+
+
+logger = logging.getLogger('pre_commit')
+
+
+def _start_msg(*, start: str, cols: int, end_len: int) -> str:
+    dots = '.' * (cols - len(start) - end_len - 1)
+    return f'{start}{dots}'
+
+
+def _full_msg(
+        *,
+        start: str,
+        cols: int,
+        end_msg: str,
+        end_color: str,
+        use_color: bool,
+        postfix: str = '',
+) -> str:
+    dots = '.' * (cols - len(start) - len(postfix) - len(end_msg) - 1)
+    end = color.format_color(end_msg, end_color, use_color)
+    return f'{start}{dots}{postfix}{end}\n'
+
+
+def filter_by_include_exclude(
+        names: Collection[str],
+        include: str,
+        exclude: str,
+) -> List[str]:
+    include_re, exclude_re = re.compile(include), re.compile(exclude)
+    return [
+        filename for filename in names
+        if include_re.search(filename)
+        if not exclude_re.search(filename)
+    ]
+
+
+class Classifier:
+    def __init__(self, filenames: Sequence[str]) -> None:
+        # on windows we normalize all filenames to use forward slashes
+        # this makes it easier to filter using the `files:` regex
+        # this also makes improperly quoted shell-based hooks work better
+        # see #1173
+        if os.altsep == '/' and os.sep == '\\':
+            filenames = [f.replace(os.sep, os.altsep) for f in filenames]
+        self.filenames = [f for f in filenames if os.path.lexists(f)]
+
+    @functools.lru_cache(maxsize=None)
+    def _types_for_file(self, filename: str) -> Set[str]:
+        return tags_from_path(filename)
+
+    def by_types(
+            self,
+            names: Sequence[str],
+            types: Collection[str],
+            exclude_types: Collection[str],
+    ) -> List[str]:
+        types, exclude_types = frozenset(types), frozenset(exclude_types)
+        ret = []
+        for filename in names:
+            tags = self._types_for_file(filename)
+            if tags >= types and not tags & exclude_types:
+                ret.append(filename)
+        return ret
+
+    def filenames_for_hook(self, hook: Hook) -> Tuple[str, ...]:
+        names = self.filenames
+        names = filter_by_include_exclude(names, hook.files, hook.exclude)
+        names = self.by_types(names, hook.types, hook.exclude_types)
+        return tuple(names)
+
+
+def _get_skips(environ: EnvironT) -> Set[str]:
+    skips = environ.get('SKIP', '')
+    return {skip.strip() for skip in skips.split(',') if skip.strip()}
+
+
+SKIPPED = 'Skipped'
+NO_FILES = '(no files to check)'
+
+
+def _subtle_line(s: str, use_color: bool) -> None:
+    output.write_line(color.format_color(s, color.SUBTLE, use_color))
+
+
+def _run_single_hook(
+        classifier: Classifier,
+        hook: Hook,
+        skips: Set[str],
+        cols: int,
+        verbose: bool,
+        use_color: bool,
+) -> bool:
+    filenames = classifier.filenames_for_hook(hook)
+
+    if hook.id in skips or hook.alias in skips:
+        output.write(
+            _full_msg(
+                start=hook.name,
+                end_msg=SKIPPED,
+                end_color=color.YELLOW,
+                use_color=use_color,
+                cols=cols,
+            ),
+        )
+        duration = None
+        retcode = 0
+        files_modified = False
+        out = b''
+    elif not filenames and not hook.always_run:
+        output.write(
+            _full_msg(
+                start=hook.name,
+                postfix=NO_FILES,
+                end_msg=SKIPPED,
+                end_color=color.TURQUOISE,
+                use_color=use_color,
+                cols=cols,
+            ),
+        )
+        duration = None
+        retcode = 0
+        files_modified = False
+        out = b''
+    else:
+        # print hook and dots first in case the hook takes a while to run
+        output.write(_start_msg(start=hook.name, end_len=6, cols=cols))
+
+        diff_cmd = ('git', 'diff', '--no-ext-diff')
+        diff_before = cmd_output_b(*diff_cmd, retcode=None)
+        if not hook.pass_filenames:
+            filenames = ()
+        time_before = time.time()
+        language = languages[hook.language]
+        retcode, out = language.run_hook(hook, filenames, use_color)
+        duration = round(time.time() - time_before, 2) or 0
+        diff_after = cmd_output_b(*diff_cmd, retcode=None)
+
+        # if the hook makes changes, fail the commit
+        files_modified = diff_before != diff_after
+
+        if retcode or files_modified:
+            print_color = color.RED
+            status = 'Failed'
+        else:
+            print_color = color.GREEN
+            status = 'Passed'
+
+        output.write_line(color.format_color(status, print_color, use_color))
+
+    if verbose or hook.verbose or retcode or files_modified:
+        _subtle_line(f'- hook id: {hook.id}', use_color)
+
+        if (verbose or hook.verbose) and duration is not None:
+            _subtle_line(f'- duration: {duration}s', use_color)
+
+        if retcode:
+            _subtle_line(f'- exit code: {retcode}', use_color)
+
+        # Print a message if failing due to file modifications
+        if files_modified:
+            _subtle_line('- files were modified by this hook', use_color)
+
+        if out.strip():
+            output.write_line()
+            output.write_line_b(out.strip(), logfile_name=hook.log_file)
+            output.write_line()
+
+    return files_modified or bool(retcode)
+
+
+def _compute_cols(hooks: Sequence[Hook]) -> int:
+    """Compute the number of columns to display hook messages.  The widest
+    that will be displayed is in the no files skipped case:
+
+        Hook name...(no files to check) Skipped
+    """
+    if hooks:
+        name_len = max(len(hook.name) for hook in hooks)
+    else:
+        name_len = 0
+
+    cols = name_len + 3 + len(NO_FILES) + 1 + len(SKIPPED)
+    return max(cols, 80)
+
+
+def _all_filenames(args: argparse.Namespace) -> Collection[str]:
+    if args.hook_stage == 'post-checkout':  # no files for post-checkout
+        return ()
+    elif args.hook_stage in {'prepare-commit-msg', 'commit-msg'}:
+        return (args.commit_msg_filename,)
+    elif args.from_ref and args.to_ref:
+        return git.get_changed_files(args.from_ref, args.to_ref)
+    elif args.files:
+        return args.files
+    elif args.all_files:
+        return git.get_all_files()
+    elif git.is_in_merge_conflict():
+        return git.get_conflicted_files()
+    else:
+        return git.get_staged_files()
+
+
+def _run_hooks(
+        config: Dict[str, Any],
+        hooks: Sequence[Hook],
+        args: argparse.Namespace,
+        environ: EnvironT,
+) -> int:
+    """Actually run the hooks."""
+    skips = _get_skips(environ)
+    cols = _compute_cols(hooks)
+    filenames = filter_by_include_exclude(
+        _all_filenames(args), config['files'], config['exclude'],
+    )
+    classifier = Classifier(filenames)
+    retval = 0
+    for hook in hooks:
+        retval |= _run_single_hook(
+            classifier, hook, skips, cols,
+            verbose=args.verbose, use_color=args.color,
+        )
+        if retval and config['fail_fast']:
+            break
+    if retval and args.show_diff_on_failure and git.has_diff():
+        if args.all_files:
+            output.write_line(
+                'pre-commit hook(s) made changes.\n'
+                'If you are seeing this message in CI, '
+                'reproduce locally with: `pre-commit run --all-files`.\n'
+                'To run `pre-commit` as part of git workflow, use '
+                '`pre-commit install`.',
+            )
+        output.write_line('All changes made by hooks:')
+        # args.color is a boolean.
+        # See user_color function in color.py
+        git_color_opt = 'always' if args.color else 'never'
+        subprocess.call((
+            'git', '--no-pager', 'diff', '--no-ext-diff',
+            f'--color={git_color_opt}',
+        ))
+
+    return retval
+
+
+def _has_unmerged_paths() -> bool:
+    _, stdout, _ = cmd_output_b('git', 'ls-files', '--unmerged')
+    return bool(stdout.strip())
+
+
+def _has_unstaged_config(config_file: str) -> bool:
+    retcode, _, _ = cmd_output_b(
+        'git', 'diff', '--no-ext-diff', '--exit-code', config_file,
+        retcode=None,
+    )
+    # be explicit, other git errors don't mean it has an unstaged config.
+    return retcode == 1
+
+
+def run(
+        config_file: str,
+        store: Store,
+        args: argparse.Namespace,
+        environ: EnvironT = os.environ,
+) -> int:
+    stash = not args.all_files and not args.files
+
+    # Check if we have unresolved merge conflict files and fail fast.
+    if _has_unmerged_paths():
+        logger.error('Unmerged files.  Resolve before committing.')
+        return 1
+    if bool(args.from_ref) != bool(args.to_ref):
+        logger.error('Specify both --from-ref and --to-ref.')
+        return 1
+    if stash and _has_unstaged_config(config_file):
+        logger.error(
+            f'Your pre-commit configuration is unstaged.\n'
+            f'`git add {config_file}` to fix this.',
+        )
+        return 1
+    if (
+            args.hook_stage in {'prepare-commit-msg', 'commit-msg'} and
+            not args.commit_msg_filename
+    ):
+        logger.error(
+            f'`--commit-msg-filename` is required for '
+            f'`--hook-stage {args.hook_stage}`',
+        )
+        return 1
+
+    # Expose from-ref / to-ref as environment variables for hooks to consume
+    if args.from_ref and args.to_ref:
+        # legacy names
+        environ['PRE_COMMIT_ORIGIN'] = args.from_ref
+        environ['PRE_COMMIT_SOURCE'] = args.to_ref
+        # new names
+        environ['PRE_COMMIT_FROM_REF'] = args.from_ref
+        environ['PRE_COMMIT_TO_REF'] = args.to_ref
+
+    if args.remote_name and args.remote_url:
+        environ['PRE_COMMIT_REMOTE_NAME'] = args.remote_name
+        environ['PRE_COMMIT_REMOTE_URL'] = args.remote_url
+
+    if args.checkout_type:
+        environ['PRE_COMMIT_CHECKOUT_TYPE'] = args.checkout_type
+
+    with contextlib.ExitStack() as exit_stack:
+        if stash:
+            exit_stack.enter_context(staged_files_only(store.directory))
+
+        config = load_config(config_file)
+        hooks = [
+            hook
+            for hook in all_hooks(config, store)
+            if not args.hook or hook.id == args.hook or hook.alias == args.hook
+            if args.hook_stage in hook.stages
+        ]
+
+        if args.hook and not hooks:
+            output.write_line(
+                f'No hook with id `{args.hook}` in stage `{args.hook_stage}`',
+            )
+            return 1
+
+        install_hook_envs(hooks, store)
+
+        return _run_hooks(config, hooks, args, environ)
+
+    # https://github.com/python/mypy/issues/7726
+    raise AssertionError('unreachable')
diff --git a/pre_commit/commands/sample_config.py b/pre_commit/commands/sample_config.py
new file mode 100644
index 0000000..d435faa
--- /dev/null
+++ b/pre_commit/commands/sample_config.py
@@ -0,0 +1,21 @@
+# TODO: maybe `git ls-remote git://github.com/pre-commit/pre-commit-hooks` to
+# determine the latest revision?  This adds ~200ms from my tests (and is
+# significantly faster than https:// or http://).  For now, periodically
+# manually updating the revision is fine.
+SAMPLE_CONFIG = '''\
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.4.0
+    hooks:
+    -   id: trailing-whitespace
+    -   id: end-of-file-fixer
+    -   id: check-yaml
+    -   id: check-added-large-files
+'''
+
+
+def sample_config() -> int:
+    print(SAMPLE_CONFIG, end='')
+    return 0
diff --git a/pre_commit/commands/try_repo.py b/pre_commit/commands/try_repo.py
new file mode 100644
index 0000000..4aee209
--- /dev/null
+++ b/pre_commit/commands/try_repo.py
@@ -0,0 +1,77 @@
+import argparse
+import logging
+import os.path
+from typing import Optional
+from typing import Tuple
+
+import pre_commit.constants as C
+from pre_commit import git
+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_b
+from pre_commit.util import tmpdir
+from pre_commit.util import yaml_dump
+from pre_commit.xargs import xargs
+
+logger = logging.getLogger(__name__)
+
+
+def _repo_ref(tmpdir: str, repo: str, ref: Optional[str]) -> Tuple[str, str]:
+    # if `ref` is explicitly passed, use it
+    if ref is not None:
+        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_b('git', 'clone', repo, shadow)
+        cmd_output_b('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)
+
+        staged_files = git.get_staged_files(cwd=repo)
+        if staged_files:
+            xargs(('git', 'add', '--'), staged_files, cwd=repo, env=env)
+
+        cmd_output_b('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: argparse.Namespace) -> int:
+    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(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]
+
+        config = {'repos': [{'repo': repo, 'rev': ref, 'hooks': hooks}]}
+        config_s = yaml_dump(config)
+
+        config_filename = os.path.join(tempdir, C.CONFIG_FILE)
+        with open(config_filename, 'w') as cfg:
+            cfg.write(config_s)
+
+        output.write_line('=' * 79)
+        output.write_line('Using config:')
+        output.write_line('=' * 79)
+        output.write(config_s)
+        output.write_line('=' * 79)
+
+        return run(config_filename, store, args)