Tools/Scripts/hooks/prepare-commit-msg

#!/usr/bin/env {{ python }}

import os
import re
import subprocess
import sys

LOCATION = r'{{ location }}'
SPACING = 8
SCRIPTS = os.path.dirname(os.path.dirname(LOCATION))
CHERRY_PICKING_RE = re.compile(r'^# You are currently cherry-picking commit (?P<hash>[a-f0-9A-F]+)\.$')
IDENTIFIER_RE = re.compile(r'(\d+\.)?\d+@\S+')
PREFER_RADAR = {{ prefer_radar }}

DEFAULT_BRANCH = '{{ default_branch }}'
SOURCE_REMOTES = {{ source_remotes }}
TRAILERS_TO_STRIP = {{ trailers_to_strip }}

ENCODING_KWARGS = dict()
if sys.version_info >= (3, 6):
    ENCODING_KWARGS = dict(encoding='utf-8')

sys.path.append(SCRIPTS)
from webkitpy.common.checkout.diff_parser import DiffParser
from webkitbugspy import radar


BRANCH = subprocess.check_output(['git', 'rev-parse', '--abbrev-ref', 'HEAD'], **ENCODING_KWARGS).strip()
for name, variable in dict(
    title='COMMIT_MESSAGE_TITLE',
    bug='COMMIT_MESSAGE_BUG',
    cherry_picked='GIT_WEBKIT_CHERRY_PICKED',
).items():
    if variable in os.environ:
        continue
    try:
        value = subprocess.check_output(
            ['git', 'config', '--get-all', 'branch.{}.{}'.format(BRANCH, name)],
            stderr=subprocess.PIPE,
            **ENCODING_KWARGS
        ).strip()
        if value:
            os.environ[variable] = value
    except subprocess.CalledProcessError as error:
        # `1` means that key did not exist, which is valid.
        if error.returncode != 1:
            sys.stderr.write(error.stderr)


def get_bugs_string():
    """Determines what bug URLs to fill or suggest in a WebKit commit message."""
    need_the_bug_url = 'Need the bug URL (OOPS!).'
    need_the_radar = 'Include a Radar link (OOPS!).'
    has_radar = any([bool(regex.match(line))
                     for line in os.environ.get('COMMIT_MESSAGE_BUG', '').splitlines()
                     for regex in radar.Tracker.RES])

    if os.environ.get('COMMIT_MESSAGE_BUG'):
        if has_radar or not bool(radar.Tracker.radarclient()):
            return os.environ['COMMIT_MESSAGE_BUG']
        else:
            return os.environ['COMMIT_MESSAGE_BUG'] + '\n' + need_the_radar

    bugs_string = need_the_bug_url
    if bool(radar.Tracker.radarclient()):
        bugs_string += '\n' + need_the_radar
    return bugs_string

def parseChanges(command, commit_message):
    dirname = None

    try:
        for line in subprocess.check_output(
            command,
            **ENCODING_KWARGS
        ).splitlines():
            if line == '~':
                dirname = None
                continue
            if line.startswith(' ' * SPACING):
                if dirname:
                    line = line.replace('* ', '* {}/'.format(dirname))
                commit_message.append(line[SPACING:])
                continue
            if line.endswith(':'):
                dirname = line.split(':')[0]
                continue
    except subprocess.CalledProcessError:
        commit_message.append('')
        return

def message(source=None, sha=None):
    commit_message = []
    command = ['perl', os.path.join(SCRIPTS, 'prepare-ChangeLog'), '--no-write', '--only-files', '--delimiters', '--git-index']

    if sha:
        commit_message.append('Amend changes:')
        parseChanges(command, commit_message)
        commit_message.append('')

        commit_message.append('Combined changes:')
        command.append('--git-commit')
        command.append('HEAD')

    parseChanges(command, commit_message)

    bugs_string = get_bugs_string()

    return '''{title}
{bugs}

Reviewed by NOBODY (OOPS!).

Explanation of why this fixes the bug (OOPS!).

{content}
'''.format(
        title=os.environ.get('COMMIT_MESSAGE_TITLE', '') or 'Need a short description (OOPS!).',
        bugs=bugs_string,
        content='\n'.join(commit_message) + os.environ.get('COMMIT_MESSAGE_CONTENT', ''),
    )


def source_branches():
    proc = None
    try:
        proc = subprocess.Popen(
            ['git', 'rev-list', 'HEAD'],
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            **ENCODING_KWARGS
        )
        outer_line = proc.stdout.readline()
        while outer_line:
            branches = set()
            for inner_line in subprocess.check_output(
                ['git', 'branch', '--contains', outer_line.strip(), '-a', '--format', '%(refname)'],
                **ENCODING_KWARGS
            ).splitlines():
                if not inner_line.startswith('refs/remotes'):
                    continue
                _, _, remote, branch = inner_line.split('/', 3)
                if remote in SOURCE_REMOTES and branch != 'HEAD':
                    branches.add(branch)
            if branches:
                return sorted(branches)
            outer_line = proc.stdout.readline()
    finally:
        if proc and proc.poll() is None:
            proc.kill()

    return []


def cherry_pick(content):
    cherry_picked = os.environ.get('GIT_WEBKIT_CHERRY_PICKED')
    bugs = os.environ.get('COMMIT_MESSAGE_BUG', '').splitlines()
    bug = bugs[0] if bugs else None

    if PREFER_RADAR and not bug:
        RADAR_RES = [
            re.compile(r'<?rdar://problem/(?P<id>\d+)>?'),
            re.compile(r'<?radar://problem/(?P<id>\d+)>?'),
            re.compile(r'<?rdar:\/\/(?P<id>\d+)>?'),
            re.compile(r'<?radar:\/\/(?P<id>\d+)>?'),
        ]
        seen_empty = False
        for line in content.splitlines():
            if not line and seen_empty:
                break
            elif not line:
                seen_empty = True
                continue
            words = line.split()
            for word in [words[0], words[-1]] if words[0] != words[-1] else [words[0]]:
                for regex in RADAR_RES:
                    if regex.match(word):
                        bug = word
                        break
                if bug:
                    break

    if not cherry_picked or not bug:
        LINK_RE = re.compile(r'^\S+:\/\/\S+\d+\S*$')

        last_line = ''
        for line in content.splitlines():
            if not line:
                continue
            if not line.startswith('#'):
                last_line = line
            if not bug and LINK_RE.match(line):
                bug = line
            match = None if cherry_picked else CHERRY_PICKING_RE.match(line)
            if match:
                cherry_picked = match.group('hash')

            if bug and cherry_picked:
                break

        if last_line and (not cherry_picked or not IDENTIFIER_RE.search(cherry_picked)):
            from_last_line = IDENTIFIER_RE.search(last_line)
            if from_last_line and not cherry_picked:
                cherry_picked = from_last_line.group(0)
            elif from_last_line:
                cherry_picked = '{} ({})'.format(from_last_line.group(0), cherry_picked)

    is_trunk_bound = DEFAULT_BRANCH in source_branches()
    in_suffix = False
    cherry_pick_metadata = '{}. {}'.format(cherry_picked or '???', bug or '<bug>')
    result = []
    if not is_trunk_bound:
        result += ['Cherry-pick {}'.format(cherry_pick_metadata), '']
    for line in content.splitlines():
        line = line.rstrip()
        if not line:
            result.append('')
            continue
        if line[0] == '#' and not in_suffix:
            in_suffix = True
            if is_trunk_bound:
                while len(result) and not result[-1] or (result[-1].split(':', 1)[0] in TRAILERS_TO_STRIP):
                    del result[-1]
                result += ['', 'Originally-landed-as: {}'.format(cherry_pick_metadata)]
        if line[0] != '#' and not is_trunk_bound:
            result.append(4*' ' + line)
        else:
            result.append(line)
    return '\n'.join(result)


def main(file_name=None, source=None, sha=None):
    with open(file_name, 'r') as commit_message_file:
        content = commit_message_file.read()

    if source not in (None, 'commit', 'template', 'merge'):
        return 0

    for line in content.splitlines():
        if CHERRY_PICKING_RE.match(line):
            os.environ['GIT_REFLOG_ACTION'] = 'cherry-pick'
            break

    if source == 'merge' and os.environ.get('GIT_REFLOG_ACTION') == 'cherry-pick':
        with open(file_name, 'w') as commit_message_file:
            commit_message_file.write(cherry_pick(content))
        return 0

    if source == 'merge' and not content.startswith('Revert'):
        return 0

    if os.environ.get('GIT_EDITOR', '') == ':':
        # When there's no editor being launched, do nothing.
        return 0

    with open(file_name, 'w') as commit_message_file:
        if sha:
            commit_message_file.write(subprocess.check_output(
                ['git', 'log', sha, '-1', '--pretty=format:%B'],
                **ENCODING_KWARGS
            ))
        else:
            commit_message_file.write(message(source=source, sha=sha))

        commit_message_file.write('''
# Please populate the above commit message. Lines starting
# with '#' will be ignored

''')
        if sha:
            for line in message(source=source, sha=sha).splitlines():
                commit_message_file.write('# {}\n'.format(line))
            commit_message_file.write('\n')
        for line in subprocess.check_output(
            ['git', 'status'],
            **ENCODING_KWARGS
        ).splitlines():
            commit_message_file.write('# {}\n'.format(line))

    return 0


if __name__ == '__main__':
    sys.exit(main(*sys.argv[1:]))