#!/usr/bin/python -u
# vim: set fileencoding=utf-8 :
#
# (C) 2007, 2008, 2009, 2010 Guido Guenther <agx@sigxcpu.org>
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
"""Generate Debian changelog entries from git commit messages"""

import ConfigParser
import os.path
import re
import sys
import shutil
import subprocess
import gbp.command_wrappers as gbpc
import gbp.dch as dch
import gbp.log
from gbp.git import (GitRepositoryError, GitRepository, build_tag, tag_to_version)
from gbp.config import GbpOptionParser, GbpOptionGroup
from gbp.errors import GbpError
from gbp.deb import parse_changelog, NoChangelogError, is_native, compare_versions

user_customizations = {}
snapshot_re = re.compile("\s*\*\* SNAPSHOT build @(?P<commit>[a-z0-9]+)\s+\*\*")


def system(cmd):
    try:
        gbpc.Command(cmd, shell=True)()
    except gbpc.CommandExecFailed:
        raise GbpError


def spawn_dch(msg=[], author=None, email=None, newversion=False, version=None,
              release=False, distribution=None, dch_options=''):
    """
    Spawn dch
    param author: committers name
    param email: committers email
    param newversion: start a new version
    version: the verion to use
    release: finalize changelog for releaze
    distribution: distribution to use
    dch_options: options passed verbatim to dch
    """
    distopt = ""
    versionopt = ""
    env = ""

    if newversion:
        if version:
            try:
                versionopt = version['increment']
            except KeyError:
                versionopt = '--newversion=%s' % version['version']
        else:
            versionopt = '-i'
    elif release:
        versionopt = "--release --no-force-save-on-release"
        msg = None

    if author and email:
        env = """DEBFULLNAME="%s" DEBEMAIL="%s" """ % (author, email)

    if distribution:
        distopt = "--distribution=%s" % distribution

    cmd = '%(env)s dch --no-auto-nmu  %(distopt)s %(versionopt)s %(dch_options)s ' % locals()
    if msg:
        cmd += '-- "[[[insert-git-dch-commit-message-here]]]"'
    else:
        cmd += '-- ""'
    system(cmd)
    if msg:
        old_cl = open("debian/changelog", "r")
        new_cl = open("debian/changelog.bak", "w")
        for line in old_cl:
            if line == "  * [[[insert-git-dch-commit-message-here]]]\n":
                print >> new_cl, "  * " + msg[0]
                for line in msg[1:]:
                    print >> new_cl, "    " + line
            else:
                print >> new_cl, line,
        os.rename("debian/changelog.bak", "debian/changelog")


def add_changelog_entry(msg, author, email, dch_options):
    "add a single changelog entry"
    spawn_dch(msg=msg, author=author, email=email, dch_options=dch_options)


def add_changelog_section(msg, distribution, repo, options, cp,
                          author=None, email=None, version=None, dch_options=''):
    "add a new changelog section"
    # If no version(change) was specified guess the new version based on the
    # latest upstream version on the upstream branch
    if not version and not is_native(cp):
        pattern = options.upstream_tag.replace('%(version)s', '*')
        try:
            tag = repo.find_tag('HEAD', pattern=pattern)
            upstream = tag_to_version(tag, options.upstream_tag)
            if upstream:
                gbp.log.debug("Found %s." % upstream)
                new_version = "%s-1" % upstream
                if compare_versions(upstream, cp['Version']) > 0:
                    version['version'] = new_version
        except GitRepositoryError:
            gbp.log.debug("No tag found matching pattern %s." % pattern)
    spawn_dch(msg=msg, newversion=True, version=version, author=author, email=email,
              distribution=distribution, dch_options=dch_options)


def get_author_email(repo, use_git_config):
    """Get author and email from git configuration"""
    author = email = None

    if use_git_config:
        try: author = repo.get_config('user.name')
        except KeyError: pass

        try: email = repo.get_config('user.email')
        except KeyError: pass
    return author, email


def fixup_trailer(repo, git_author, dch_options):
    """fixup the changelog trailer's comitter and email address - it might
    otherwise point to the last git committer instead of the person creating
    the changelog"""
    author, email = get_author_email(repo, git_author)
    spawn_dch(msg='', author=author, email=email, dch_options=dch_options)


def head_commit(repo):
    """get the full sha1 of the last commit on HEAD"""
    return repo.rev_parse('HEAD')


def snapshot_version(version):
    """
    get the current release and snapshot version
    Format is <debian-version>~<release>.gbp<short-commit-id>
    """
    try:
        (release, suffix) = version.rsplit('~', 1)
        (snapshot, commit)  = suffix.split('.', 1)
        if not commit.startswith('gbp'):
            raise ValueError
        else:
            snapshot = int(snapshot)
    except ValueError: # not a snapshot release
        release = version
        snapshot = 0
    return release, snapshot


def mangle_changelog(changelog, cp, snapshot=''):
    """
    Mangle changelog to either add or remove snapshot markers

    @param snapshot: SHA1 if snapshot header should be added/maintained, empty if it should be removed
    @type  snapshot: str
    """
    try:
        tmpfile = '%s.%s' % (changelog, snapshot)
        cw = file(tmpfile, 'w')
        cr = file(changelog, 'r')

        cr.readline() # skip version and empty line
        cr.readline()
        print >>cw, "%(Source)s (%(MangledVersion)s) %(Distribution)s; urgency=%(urgency)s\n" % cp

        line = cr.readline()
        if snapshot_re.match(line):
            cr.readline() # consume the empty line after the snapshot header
            line = ''

        if snapshot:
            print >>cw, "  ** SNAPSHOT build @%s **\n" % snapshot

        if line:
            print >>cw, line.rstrip()
        shutil.copyfileobj(cr, cw)
        cw.close()
        cr.close()
        os.unlink(changelog)
        os.rename(tmpfile, changelog)
    except OSError, e:
        raise GbpError, "Error mangling changelog %s" % e


def do_release(changelog, repo, cp, git_author, dch_options):
    "remove the snapshot header and set the distribution"
    author, email = get_author_email(repo, git_author)
    (release, snapshot) = snapshot_version(cp['Version'])
    if snapshot:
        cp['MangledVersion'] = release
        mangle_changelog(changelog, cp)
    spawn_dch(release=True, author=author, email=email, dch_options=dch_options)


def do_snapshot(changelog, repo, next_snapshot):
    """
    Add new snapshot banner to most recent changelog section. The next snapshot
    number is calculated by eval()'ing next_snapshot
    """
    commit = head_commit(repo)

    cp = parse_changelog(filename=changelog)
    (release, snapshot) = snapshot_version(cp['Version'])
    snapshot = int(eval(next_snapshot))

    suffix = "%d.gbp%s" % (snapshot, "".join(commit[0:6]))
    cp['MangledVersion'] = "%s~%s" % (release, suffix)

    mangle_changelog(changelog, cp, commit)
    return snapshot, commit


def parse_commit(repo, commitid, opts, last_commit=False):
    """parse a commit and return message, author, and author email"""
    commit_info = repo.get_commit_info(commitid)
    author = commit_info['author']
    email = commit_info['email']
    format_entry = user_customizations.get('format_changelog_entry')
    if not format_entry:
        format_entry = dch.format_changelog_entry
    entry = format_entry(commit_info, opts, last_commit=last_commit)
    return entry, (author, email)


def guess_snapshot_commit(cp, repo, options):
    """
    guess the last commit documented in the changelog from the snapshot banner
    or the last point the changelog was touched.
    """
    sr = re.search(snapshot_re, cp['Changes'])
    if sr:
        return sr.group('commit')
    # If the current topmost changelog entry has already been tagged rely on
    # the version information only. The upper level relies then on the version
    # info anyway:
    if repo.find_version(options.debian_tag, cp['Version']):
        return None
    # If we didn't find a snapshot header we look at the point the changelog
    # was last touched.
    last = repo.commits(paths="debian/changelog", options=["-1"])
    if last:
        gbp.log.info("Changelog last touched at '%s'" % last[0])
        return last[0]
    return None


def get_customizations(customization_file):
    if customization_file:
        execfile(customization_file,
                 user_customizations,
                 user_customizations)


def process_options(options, parser):
    if options.snapshot and options.release:
        parser.error("'--snapshot' and '--release' are incompatible options")

    if options.since and options.auto:
        parser.error("'--since' and '--auto' are incompatible options")

    if options.multimaint_merge:
        dch_options = "--multimaint-merge"
    else:
        dch_options = "--nomultimaint-merge"

    if options.multimaint:
        dch_options += " --multimaint"
    else:
        dch_options += " --nomultimaint"

    get_customizations(options.customization_file)
    return dch_options


def process_editor_option(options):
    # Determine Editor and check if we need it
    states = ['always']

    if options.snapshot:
        states.append("snapshot")
    elif options.release:
        states.append("release")

    if options.spawn_editor in states:
        return "sensible-editor"
    else:
        return None


def main(argv):
    ret = 0
    changelog = 'debian/changelog'
    until = 'HEAD'
    found_snapshot_header = False
    version_change = {}

    try:
        parser = GbpOptionParser(command=os.path.basename(argv[0]), prefix='',
                                 usage='%prog [options] paths')
    except ConfigParser.ParsingError, err:
        gbp.log.errror(err)
        return 1
    range_group = GbpOptionGroup(parser, "commit range options", "which commits to add to the changelog")
    version_group = GbpOptionGroup(parser, "release & version number options", "what version number and release to use")
    commit_group = GbpOptionGroup(parser, "commit message formatting", "howto format the changelog entries")
    naming_group = GbpOptionGroup(parser, "branch and tag naming", "branch names and tag formats")
    custom_group = GbpOptionGroup(parser, "customization", "options for customization")
    parser.add_option_group(range_group)
    parser.add_option_group(version_group)
    parser.add_option_group(commit_group)
    parser.add_option_group(naming_group)
    parser.add_option_group(custom_group)

    parser.add_boolean_config_file_option(option_name = "ignore-branch", dest="ignore_branch")
    naming_group.add_config_file_option(option_name="debian-branch", dest="debian_branch")
    naming_group.add_config_file_option(option_name="upstream-tag", dest="upstream_tag")
    naming_group.add_config_file_option(option_name="debian-tag", dest="debian_tag")
    naming_group.add_config_file_option(option_name="snapshot-number", dest="snapshot_number",
                      help="expression to determine the next snapshot number, default is '%(snapshot-number)s'")
    parser.add_config_file_option(option_name="git-log", dest="git_log",
                      help="options to pass to git-log, default is '%(git-log)s'")
    parser.add_option("-v", "--verbose", action="store_true", dest="verbose", default=False,
                      help="verbose command execution")
    parser.add_config_file_option(option_name="color", dest="color", type='tristate')
    range_group.add_option("-s", "--since", dest="since", help="commit to start from (e.g. HEAD^^^, debian/0.4.3)")
    range_group.add_option("-a", "--auto", action="store_true", dest="auto", default=False,
                      help="autocomplete changelog from last snapshot or tag")
    version_group.add_option("-R", "--release", action="store_true", dest="release", default=False,
                      help="mark as release")
    version_group.add_option("-S", "--snapshot", action="store_true", dest="snapshot", default=False,
                      help="mark as snapshot build")
    version_group.add_option("-N", "--new-version", dest="new_version",
                      help="use this as base for the new version number")
    version_group.add_option("--bpo", dest="bpo", action="store_true", default=False,
                      help="Increment the Debian release number for an upload to lenny-backports, and add a backport upload changelog comment.")
    version_group.add_option("--nmu", dest="nmu", action="store_true", default=False,
                      help="Increment  the  Debian  release  number  for a non-maintainer upload")
    version_group.add_option("--qa", dest="qa", action="store_true", default=False,
                      help="Increment the Debian release number for a Debian QA Team upload, and add a QA upload changelog comment.")
    version_group.add_boolean_config_file_option(option_name="git-author", dest="git_author")
    commit_group.add_boolean_config_file_option(option_name="meta", dest="meta")
    commit_group.add_config_file_option(option_name="meta-closes", dest="meta_closes",
                      help="Meta tags for the bts close commands, default is '%(meta-closes)s'")
    commit_group.add_boolean_config_file_option(option_name="full", dest="full")
    commit_group.add_config_file_option(option_name="id-length", dest="idlen",
                      help="include N digits of the commit id in the changelog entry, default is '%(id-length)s'",
                      type="int", metavar="N")
    commit_group.add_config_file_option(option_name="ignore-regex", dest="ignore_regex",
                      help="Ignore commit lines matching regex, default is '%(ignore-regex)s'")
    commit_group.add_boolean_config_file_option(option_name="multimaint", dest="multimaint")
    commit_group.add_boolean_config_file_option(option_name="multimaint-merge", dest="multimaint_merge")
    commit_group.add_config_file_option(option_name="spawn-editor", dest="spawn_editor")

    help_msg = 'Load Python code from CUSTOMIZATION_FILE.  At the moment,' \
        + ' the only useful thing the code can do is define a custom' \
        + ' format_changelog_entry() function.'
    custom_group.add_config_file_option(option_name="customizations",
                                        dest="customization_file",
                                        help=help_msg)

    (options, args) = parser.parse_args(argv[1:])
    gbp.log.setup(options.color, options.verbose)
    dch_options = process_options(options, parser)
    editor_cmd = process_editor_option(options)

    try:
        try:
            repo = GitRepository('.')
        except GitRepositoryError:
            raise GbpError, "%s is not a git repository" % (os.path.abspath('.'))

        branch = repo.get_branch()
        if options.debian_branch != branch and not options.ignore_branch:
            gbp.log.err("You are not on branch '%s' but on '%s'" % (options.debian_branch, branch))
            raise GbpError, "Use --ignore-branch to ignore or --debian-branch to set the branch name."

        cp = parse_changelog(filename=changelog)

        if options.since:
            since = options.since
        else:
            since = ''
            if options.auto:
                since = guess_snapshot_commit(cp, repo, options)
                if since:
                    gbp.log.info("Continuing from commit '%s'" % since)
                    found_snapshot_header = True
                else:
                    gbp.log.info("Couldn't find snapshot header, using version info")
            if not since:
                since = repo.find_version(options.debian_tag, cp['Version'])
                if not since:
                    raise GbpError, "Version %s not found" % cp['Version']

        if args:
            gbp.log.info("Only looking for changes on '%s'" % " ".join(args))
        commits = repo.commits(since=since, until=until, paths=" ".join(args), options=options.git_log.split(" "))

        # add a new changelog section if:
        if options.new_version or options.bpo or options.nmu or options.qa:
            if options.bpo:
                version_change['increment'] = '--bpo'
            elif  options.nmu:
                version_change['increment'] = '--nmu'
            elif  options.qa:
                version_change['increment'] = '--qa'
            else:
                version_change['version'] = options.new_version
            # the user wants to force a new version
            add_section = True
        elif cp['Distribution'] != "UNRELEASED" and not found_snapshot_header and commits:
            # the last version was a release and we have pending commits
            add_section = True
        elif options.snapshot and not found_snapshot_header:
            # the user want to switch to snapshot mode
            add_section = True
        else:
            add_section = False

        i = 0
        for c in commits:
            i += 1
            parsed = parse_commit(repo, c, options,
                                  last_commit = i == len(commits))
            commit_msg, (commit_author, commit_email) = parsed
            if not commit_msg:
                # Some commits can be ignored
                continue

            if add_section:
                # Add a section containing just this message (we can't
                # add an empty section with dch)
                add_changelog_section(distribution="UNRELEASED", msg=commit_msg,
                                      version=version_change,
                                      author=commit_author,
                                      email=commit_email,
                                      dch_options=dch_options,
                                      repo=repo,
                                      options=options,
                                      cp=cp)
                # Adding a section only needs to happen once.
                add_section = False
            else:
                add_changelog_entry(commit_msg, commit_author, commit_email, dch_options)


        # Show a message if there were no commits (not even ignored
        # commits).
        if not commits:
            gbp.log.info("No changes detected from %s to %s." % (since, until))

        if add_section:
            # If we end up here, then there were no commits to include,
            # so we put a dummy message in the new section.
            add_changelog_section(distribution="UNRELEASED", msg=["UNRELEASED"],
                                  version=version_change,
                                  dch_options=dch_options,
                                  repo=repo,
                                  options=options,
                                  cp=cp)

        fixup_trailer(repo, git_author=options.git_author,
                      dch_options=dch_options)

        if options.release:
            do_release(changelog, repo, cp, git_author=options.git_author,
                       dch_options=dch_options)
        elif options.snapshot:
            (snap, version) = do_snapshot(changelog, repo, options.snapshot_number)
            gbp.log.info("Changelog has been prepared for snapshot #%d at %s" % (snap, version))

        if editor_cmd:
            gbpc.Command(editor_cmd, ["debian/changelog"])()

    except (GbpError, GitRepositoryError, NoChangelogError), err:
        if len(err.__str__()):
            gbp.log.err(err)
        ret = 1
    return ret

if __name__ == "__main__":
    sys.exit(main(sys.argv))

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