1 files changed, 182 insertions, 0 deletions
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