Implement pre-commit migrate-config

pre_commit/commands/autoupdate.py

@@ -11,6 +11,7 @@ import pre_commit.constants as C
 from pre_commit import output
 from pre_commit.clientlib import is_local_repo
 from pre_commit.clientlib import load_config
+from pre_commit.commands.migrate_config import migrate_config
 from pre_commit.repository import Repository
 from pre_commit.util import CalledProcessError
 from pre_commit.util import cmd_output
@@ -104,21 +105,22 @@ def _write_new_config_file(path, output):
 def autoupdate(runner, tags_only):
     """Auto-update the pre-commit config to the latest versions of repos."""
     retv = 0
-    output_configs = []
+    retv |= migrate_config(runner, quiet=True)
+    output_repos = []
     changed = False
 
-    input_configs = load_config(runner.config_file_path)
+    input_config = load_config(runner.config_file_path)
 
-    for repo_config in input_configs['repos']:
+    for repo_config in input_config['repos']:
         if is_local_repo(repo_config):
-            output_configs.append(repo_config)
+            output_repos.append(repo_config)
             continue
         output.write('Updating {}...'.format(repo_config['repo']))
         try:
             new_repo_config = _update_repo(repo_config, runner, tags_only)
         except RepositoryCannotBeUpdatedError as error:
             output.write_line(error.args[0])
-            output_configs.append(repo_config)
+            output_repos.append(repo_config)
             retv = 1
             continue
 
@@ -127,12 +129,14 @@ def autoupdate(runner, tags_only):
             output.write_line('updating {} -> {}.'.format(
                 repo_config['sha'], new_repo_config['sha'],
             ))
-            output_configs.append(new_repo_config)
+            output_repos.append(new_repo_config)
         else:
             output.write_line('already up to date.')
-            output_configs.append(repo_config)
+            output_repos.append(repo_config)
 
     if changed:
-        _write_new_config_file(runner.config_file_path, output_configs)
+        output_config = input_config.copy()
+        output_config['repos'] = output_repos
+        _write_new_config_file(runner.config_file_path, output_config)
 
     return retv

pre_commit/commands/migrate_config.py

@@ -0,0 +1,52 @@
+from __future__ import print_function
+from __future__ import unicode_literals
+
+import io
+
+import yaml
+from aspy.yaml import ordered_load
+
+
+def _indent(s):
+    lines = s.splitlines(True)
+    return ''.join(' ' * 4 + line if line.strip() else line for line in lines)
+
+
+def _is_header_line(line):
+    return (line.startswith(('#', '---')) or not line.strip())
+
+
+def migrate_config(runner, quiet=False):
+    retv = 0
+
+    with io.open(runner.config_file_path) as f:
+        contents = f.read()
+
+    # Find the first non-header line
+    lines = contents.splitlines(True)
+    i = 0
+    while _is_header_line(lines[i]):
+        i += 1
+
+    header = ''.join(lines[:i])
+    rest = ''.join(lines[i:])
+
+    if isinstance(ordered_load(contents), list):
+        # If they are using the "default" flow style of yaml, this operation
+        # will yield a valid configuration
+        try:
+            trial_contents = header + 'repos:\n' + rest
+            yaml.load(trial_contents)
+            contents = trial_contents
+        except yaml.YAMLError:
+            contents = header + 'repos:\n' + _indent(rest)
+
+        with io.open(runner.config_file_path, 'w') as f:
+            f.write(contents)
+
+        print('Configuration has been migrated.')
+        retv = 1
+    elif not quiet:
+        print('Configuration is already migrated.')
+
+    return retv

pre_commit/main.py

@@ -14,6 +14,7 @@ from pre_commit.commands.clean import clean
 from pre_commit.commands.install_uninstall import install
 from pre_commit.commands.install_uninstall import install_hooks
 from pre_commit.commands.install_uninstall import uninstall
+from pre_commit.commands.migrate_config import migrate_config
 from pre_commit.commands.run import run
 from pre_commit.commands.sample_config import sample_config
 from pre_commit.error_handler import error_handler
@@ -131,6 +132,13 @@ def main(argv=None):
         ),
     )
 
+    migrate_config_parser = subparsers.add_parser(
+        'migrate-config',
+        help='Migrate list configuration to new map configuration.',
+    )
+    _add_color_option(migrate_config_parser)
+    _add_config_option(migrate_config_parser)
+
     run_parser = subparsers.add_parser('run', help='Run hooks.')
     _add_color_option(run_parser)
     _add_config_option(run_parser)
@@ -217,6 +225,8 @@ def main(argv=None):
             if args.tags_only:
                 logger.warning('--tags-only is the default')
             return autoupdate(runner, tags_only=not args.bleeding_edge)
+        elif args.command == 'migrate-config':
+            return migrate_config(runner)
         elif args.command == 'run':
             return run(runner, args)
         elif args.command == 'sample-config':

tests/commands/autoupdate_test.py

@@ -128,6 +128,7 @@ def test_does_not_reformat(
         out_of_date_repo, mock_out_store_directory, in_tmpdir,
 ):
     fmt = (
+        'repos:\n'
         '-   repo: {}\n'
         '    sha: {}  # definitely the version I want!\n'
         '    hooks:\n'
@@ -153,7 +154,7 @@ def test_loses_formatting_when_not_detectable(
     is abandoned.
     """
     config = (
-        '[\n'
+        'repos: [\n'
         '    {{\n'
         '        repo: {}, sha: {},\n'
         '        hooks: [\n'
@@ -171,6 +172,7 @@ def test_loses_formatting_when_not_detectable(
     autoupdate(Runner('.', C.CONFIG_FILE), tags_only=False)
     after = open(C.CONFIG_FILE).read()
     expected = (
+        'repos:\n'
         '-   repo: {}\n'
         '    sha: {}\n'
         '    hooks:\n'
@@ -284,10 +286,36 @@ def test_autoupdate_local_hooks_with_out_of_date_repo(
         out_of_date_repo.path, sha=out_of_date_repo.original_sha, check=False,
     )
     local_config = config_with_local_hooks()
-    config = [local_config, stale_config]
+    config = {'repos': [local_config, stale_config]}
     write_config('.', config)
     runner = Runner('.', C.CONFIG_FILE)
     assert autoupdate(runner, tags_only=False) == 0
     new_config_writen = load_config(runner.config_file_path)
     assert len(new_config_writen['repos']) == 2
     assert new_config_writen['repos'][0] == local_config
+
+
+def test_updates_old_format_to_new_format(tmpdir, capsys):
+    cfg = tmpdir.join(C.CONFIG_FILE)
+    cfg.write(
+        '-   repo: local\n'
+        '    hooks:\n'
+        '    -   id: foo\n'
+        '        name: foo\n'
+        '        entry: ./bin/foo.sh\n'
+        '        language: script\n',
+    )
+    ret = autoupdate(Runner(tmpdir.strpath, C.CONFIG_FILE), tags_only=True)
+    assert ret == 1
+    contents = cfg.read()
+    assert contents == (
+        'repos:\n'
+        '-   repo: local\n'
+        '    hooks:\n'
+        '    -   id: foo\n'
+        '        name: foo\n'
+        '        entry: ./bin/foo.sh\n'
+        '        language: script\n'
+    )
+    out, _ = capsys.readouterr()
+    assert out == 'Configuration has been migrated.\n'

tests/commands/migrate_config_test.py

@@ -0,0 +1,120 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import pytest
+
+import pre_commit.constants as C
+from pre_commit.commands.migrate_config import _indent
+from pre_commit.commands.migrate_config import migrate_config
+from pre_commit.runner import Runner
+
+
+@pytest.mark.parametrize(
+    ('s', 'expected'),
+    (
+        ('', ''),
+        ('a', '    a'),
+        ('foo\nbar', '    foo\n    bar'),
+        ('foo\n\nbar\n', '    foo\n\n    bar\n'),
+        ('\n\n\n', '\n\n\n'),
+    ),
+)
+def test_indent(s, expected):
+    assert _indent(s) == expected
+
+
+def test_migrate_config_normal_format(tmpdir, capsys):
+    cfg = tmpdir.join(C.CONFIG_FILE)
+    cfg.write(
+        '-   repo: local\n'
+        '    hooks:\n'
+        '    -   id: foo\n'
+        '        name: foo\n'
+        '        entry: ./bin/foo.sh\n'
+        '        language: script\n',
+    )
+    assert migrate_config(Runner(tmpdir.strpath, C.CONFIG_FILE)) == 1
+    out, _ = capsys.readouterr()
+    assert out == 'Configuration has been migrated.\n'
+    contents = cfg.read()
+    assert contents == (
+        'repos:\n'
+        '-   repo: local\n'
+        '    hooks:\n'
+        '    -   id: foo\n'
+        '        name: foo\n'
+        '        entry: ./bin/foo.sh\n'
+        '        language: script\n'
+    )
+
+
+def test_migrate_config_document_marker(tmpdir):
+    cfg = tmpdir.join(C.CONFIG_FILE)
+    cfg.write(
+        '# comment\n'
+        '\n'
+        '---\n'
+        '-   repo: local\n'
+        '    hooks:\n'
+        '    -   id: foo\n'
+        '        name: foo\n'
+        '        entry: ./bin/foo.sh\n'
+        '        language: script\n',
+    )
+    assert migrate_config(Runner(tmpdir.strpath, C.CONFIG_FILE)) == 1
+    contents = cfg.read()
+    assert contents == (
+        '# comment\n'
+        '\n'
+        '---\n'
+        'repos:\n'
+        '-   repo: local\n'
+        '    hooks:\n'
+        '    -   id: foo\n'
+        '        name: foo\n'
+        '        entry: ./bin/foo.sh\n'
+        '        language: script\n'
+    )
+
+
+def test_migrate_config_list_literal(tmpdir):
+    cfg = tmpdir.join(C.CONFIG_FILE)
+    cfg.write(
+        '[{\n'
+        '    repo: local,\n'
+        '    hooks: [{\n'
+        '        id: foo, name: foo, entry: ./bin/foo.sh,\n'
+        '        language: script,\n'
+        '    }]\n'
+        '}]',
+    )
+    assert migrate_config(Runner(tmpdir.strpath, C.CONFIG_FILE)) == 1
+    contents = cfg.read()
+    assert contents == (
+        'repos:\n'
+        '    [{\n'
+        '        repo: local,\n'
+        '        hooks: [{\n'
+        '            id: foo, name: foo, entry: ./bin/foo.sh,\n'
+        '            language: script,\n'
+        '        }]\n'
+        '    }]'
+    )
+
+
+def test_already_migrated_configuration_noop(tmpdir, capsys):
+    contents = (
+        'repos:\n'
+        '-   repo: local\n'
+        '    hooks:\n'
+        '    -   id: foo\n'
+        '        name: foo\n'
+        '        entry: ./bin/foo.sh\n'
+        '        language: script\n'
+    )
+    cfg = tmpdir.join(C.CONFIG_FILE)
+    cfg.write(contents)
+    assert not migrate_config(Runner(tmpdir.strpath, C.CONFIG_FILE))
+    out, _ = capsys.readouterr()
+    assert out == 'Configuration is already migrated.\n'
+    assert cfg.read() == contents

tests/main_test.py

@@ -12,8 +12,8 @@ from testing.auto_namedtuple import auto_namedtuple
 
 
 FNS = (
-    'autoupdate', 'clean', 'install', 'install_hooks', 'run', 'sample_config',
+    'autoupdate', 'clean', 'install', 'install_hooks', 'migrate_config', 'run',
-    'uninstall',
+    'sample_config', 'uninstall',
 )
 CMDS = tuple(fn.replace('_', '-') for fn in FNS)