update-changelog.py

from __future__ import unicode_literals, division, absolute_import

import collections
import datetime
import io
import re
import sys

from git import Repo


class MDChangeSet(object):
    """Represets a markdown changeset for a single version."""
    CATEGORIES = [
        ('### Added\n', ['add', 'added', 'feature']),
        ('### Changed\n', ['change', 'changed', 'update']),
        ('### Fixed\n', ['fix', 'fixed']),
        ('### Deprecated\n', ['deprecate', 'deprecated']),
        ('### Removed\n', ['remove', 'removed']),
    ]

    def __init__(self):
        self.pre_header = ['\n']
        self.version_header = ''
        self.post_header = []
        self.sections = collections.OrderedDict()
        self.footer = []

    @classmethod
    def from_md_lines(cls, lines):
        """Parse an existing markdown changeset section and return the VersionLog instance."""
        instance = cls()
        instance.pre_header, version_header, tail = isplit('## ', lines)
        if version_header:
            instance.version_header = version_header
        instance.post_header, section, tail = isplit('### ', tail)
        while section:
            instance.sections[section], section, tail = isplit('### ', tail)
        return instance

    def parse_message(self, message):
        """
        Parses a git commit message and formats and adds any tagged messages to this changeset.
        Returns True if one or more changelog messages was found.
        """
        found = False
        for cat, item in self.change_items(message):
            found = True
            item = re.sub('#(\d{3,4})', r'[#\1](https://github.com/Flexget/Flexget/issues/\1)', item)
            item = '- {0}\n'.format(item)
            self.sections.setdefault(cat, ['\n']).insert(0, item)
        return found

    def change_items(self, message):
        """An iterator of changelog updates from a commit message in the form (category, message)"""
        for line in message.split('\n'):
            for cat_match in re.finditer('\[(\w+)\]', line):
                found_cat = self.cat_lookup(cat_match.group(1))
                if found_cat:
                    line = line.replace(cat_match.group(0), '').strip()
                    yield found_cat, line

    def cat_lookup(self, cat):
        """Return an official category for `cat` tag text."""
        for cat_item in self.CATEGORIES:
            if cat in cat_item[1]:
                return cat_item[0]

    def to_md_lines(self):
        """An iterator over the markdown lines representing this changeset."""
        for l in self.pre_header:
            yield l
        yield self.version_header
        for l in self.post_header:
            yield l
        for section, items in self.sections.items():
            yield section
            for item in items:
                yield item
        for l in self.footer:
            yield l


def isplit(start_text, iterator):
    """Returns head, match, tail tuple, where match is the first line that starts with `start_text`"""
    head = []
    iterator = iter(iterator)
    for item in iterator:
        if item.startswith(start_text):
            return head, item, iterator
        head.append(item)
    return head, None, iterator


if __name__ == '__main__':
    try:
        filename = sys.argv[1]
    except IndexError:
        print('No filename specified, using changelog.md')
        filename = 'changelog.md'
    with io.open(filename, encoding='utf-8') as logfile:
        pre_lines, start_comment, tail = isplit('<!---', logfile)
        active_lines, end_comment, tail = isplit('<!---', tail)
        post_lines = list(tail)

    repo = Repo('.')
    cur_ver = MDChangeSet.from_md_lines(active_lines)
    latestref = re.match('<!---\s*([\d\w]+)', start_comment).group(1)
    oldestref = re.match('<!---\s*([\d\w]+)', end_comment).group(1)
    released_vers = []
    commits = list(repo.iter_commits('{0}..HEAD'.format(latestref), reverse=True))
    modified = False
    if commits:
        tags = {}
        for tag in repo.tags:
            tags[tag.commit.hexsha] = tag.tag
        for commit in commits:
            if cur_ver.parse_message(commit.message):
                modified = True
            if commit.hexsha in tags:
                modified = True
                # Tag changeset with release date and version and create new current changeset
                version = tags[commit.hexsha].tag
                release_date = datetime.datetime.fromtimestamp(tags[commit.hexsha].tagged_date).strftime('%Y-%m-%d')
                cur_ver.version_header = '## {0} ({1})\n'.format(version, release_date)
                diffstartref = oldestref
                if oldestref in tags:
                    diffstartref = tags[oldestref].tag
                cur_ver.post_header.insert(0, '[all commits](https://github.com/Flexget/Flexget/compare/{0}...{1})\n'.
                                           format(diffstartref, version))
                released_vers.insert(0, cur_ver)
                cur_ver = MDChangeSet()
                oldestref = commit.hexsha
            if cur_ver.sections and not cur_ver.version_header:
                modified = True
                verfile = repo.tree('HEAD')['flexget/_version.py'].data_stream.read()
                __version__ = None
                try:
                    exec(verfile)  # pylint: disable=W0122
                except Exception:
                    pass
                cur_ver.version_header = '## {0} (unreleased)\n'.format(__version__)

    if modified:
        print('Writing modified changelog.')
        with io.open(filename, 'w', encoding='utf-8') as logfile:
            logfile.writelines(pre_lines)
            logfile.write('<!---{0}--->\n'.format(commit.hexsha))
            logfile.writelines(cur_ver.to_md_lines())
            logfile.write('<!---{0}--->\n'.format(oldestref))
            for ver in released_vers:
                logfile.writelines(ver.to_md_lines())
            logfile.writelines(post_lines)
    else:
        print('No updates to write.')