def update_core(data, branch=None):
    msg = "Ok to update coredev versions.cfg/checkouts.cfg?"
    if branch:
        msg = "Ok to update coredev {0} versions.cfg/checkouts.cfg?".format(branch)
    if ask(msg, default=True):
        root_path = os.path.join(os.getcwd(), '../../')
        g = git.Git(root_path)
        g.pull()  # make sure buildout.coredev is up-to-date
        package_name = data['name']
        new_version = data['version']
        update_versions(package_name, new_version)
        if package_name not in ALWAYS_CHECKED_OUT_PACKAGES:
            remove_from_checkouts(package_name)
        # git commit
        message = "{0} {1}".format(package_name, new_version)
        g.add('versions.cfg')
        g.add('checkouts.cfg')
        print("Committing changes.")
        g.commit(message=message)
        msg = "Ok to push coredev?"
        if branch:
            msg = "Ok to push coredev {0}?".format(branch)
        if ask(msg, default=True):
            print("Pushing changes to server.")
            g.push()

    def ask_what_to_release(self):
        """Show changes both in CHANGES.rst and on git history

        For that checkout the repository, show both changes to see if
        everything worth writing in CHANGES.rst from git history is already
        there.
        """
        logger.info('')
        msg = 'What to release'
        logger.info(msg)
        logger.info('-' * len(msg))
        to_release = []
        for distribution_path in self.distributions:
            dist_name = distribution_path.split('/')[-1]
            repo = Repo(distribution_path)

            git_changes = get_compact_git_history(
                repo,
                self.last_tags[dist_name],
                self.branch,
            )
            cleaned_git_changes = filter_git_history(git_changes)

            # a git history without any meaningful commit should not be
            # released
            if cleaned_git_changes == '':
                continue

            logger.info(DISTRIBUTION.format(distribution_path))

            change_log_path = '{0}/CHANGES.rst'.format(repo.working_tree_dir)
            try:
                changes = self._grab_changelog(change_log_path)
            except IOError:
                logger.debug('Changelog not found, skipping.')
                continue
            self.changelogs[dist_name] = changes[2:]

            # nice to have: show them side-by-side
            logger.info('')
            logger.info(cleaned_git_changes)
            logger.info('')
            logger.info('')
            logger.info(''.join(changes))
            msg = '{0}: write the above git history on CHANGES.rst?'
            if self.test and ask(msg.format(dist_name)):
                changelog = UpdateDistChangelog(
                    distribution_path,
                    branch=self.branch,
                )
                changelog.write_changes(history=cleaned_git_changes)
            elif not self.test and \
                    ask('Is the change log ready for release?'):
                to_release.append(distribution_path)

        if not self.test:
            self.distributions = to_release

        logger.debug('Distributions: ')
        logger.debug('\n'.join(self.distributions))

def zest_releaser_check(data):
    """Check the completeness of MANIFEST.in before the release.

    This is an entry point for zest.releaser.  See the documentation at
    http://zestreleaser.readthedocs.org/en/latest/entrypoints.html
    """
    from zest.releaser.utils import ask
    source_tree = data['workingdir']
    if not is_package(source_tree):
        # You can use zest.releaser on things that are not Python packages.
        # It's pointless to run check-manifest in those circumstances.
        # See https://github.com/mgedmin/check-manifest/issues/9 for details.
        return
    if not ask("Do you want to run check-manifest?"):
        return
    try:
        if not check_manifest(source_tree):
            if not ask("MANIFEST.in is not in order. "
                       " Do you want to continue despite that?", default=False):
                sys.exit(1)
    except Failure as e:
        error(str(e))
        if not ask("Something bad happened. "
                   " Do you want to continue despite that?", default=False):
            sys.exit(2)

    def _upload_distributions(self, package, sdist_options, pypiconfig):
        # See if creating an egg actually works.
        logger.info("Making an egg of a fresh tag checkout.")
        print system(utils.setup_py('sdist ' + sdist_options))

        # First ask if we want to upload to pypi, which should always
        # work, also without collective.dist.
        use_pypi = package_in_pypi(package)
        if use_pypi:
            logger.info("This package is registered on PyPI.")
        else:
            logger.warn("This package is NOT registered on PyPI.")
        if pypiconfig.is_old_pypi_config():
            pypi_command = 'register sdist %s upload' % sdist_options
            shell_command = utils.setup_py(pypi_command)
            if use_pypi:
                default = True
                exact = False
            else:
                # We are not yet on pypi.  To avoid an 'Oops...,
                # sorry!' when registering and uploading an internal
                # package we default to False here.
                default = False
                exact = True
            if utils.ask("Register and upload to PyPI", default=default,
                         exact=exact):
                logger.info("Running: %s", shell_command)
                result = system(shell_command)
                utils.show_first_and_last_lines(result)

        # If collective.dist is installed (or we are using
        # python2.6 or higher), the user may have defined
        # other servers to upload to.
        for server in pypiconfig.distutils_servers():
            if pypi.new_distutils_available():
                commands = ('register', '-r', server, 'sdist',
                            sdist_options, 'upload', '-r', server)
            else:
                ## This would be logical, given the lines above:
                #commands = ('mregister', '-r', server, 'sdist',
                #            sdist_options, 'mupload', '-r', server)
                ## But according to the collective.dist documentation
                ## it should be this (with just one '-r'):
                commands = ('mregister', 'sdist',
                            sdist_options, 'mupload', '-r', server)
            shell_command = utils.setup_py(' '.join(commands))
            default = True
            exact = False
            if server == 'pypi' and not use_pypi:
                # We are not yet on pypi.  To avoid an 'Oops...,
                # sorry!' when registering and uploading an internal
                # package we default to False here.
                default = False
                exact = True
            if utils.ask("Register and upload to %s" % server,
                         default=default, exact=exact):
                logger.info("Running: %s", shell_command)
                result = system(shell_command)
                utils.show_first_and_last_lines(result)

    def _upload_distributions(self, package):
        # See if creating an sdist (and maybe a wheel) actually works.
        # Also, this makes the sdist (and wheel) available for plugins.
        # And for twine, who will just upload the created files.
        logger.info(
            "Making a source distribution of a fresh tag checkout (in %s).",
            self.data['tagworkingdir'])
        result = utils.execute_command(utils.setup_py('sdist'))
        utils.show_interesting_lines(result)
        if self.pypiconfig.create_wheel():
            logger.info("Making a wheel of a fresh tag checkout (in %s).",
                        self.data['tagworkingdir'])
            result = utils.execute_command(utils.setup_py('bdist_wheel'))
        utils.show_interesting_lines(result)
        if not self.pypiconfig.is_pypi_configured():
            logger.error(
                "You must have a properly configured %s file in "
                "your home dir to upload to a Python package index.",
                pypi.DIST_CONFIG_FILE)
            if utils.ask("Do you want to continue without uploading?",
                         default=False):
                return
            sys.exit(1)

        # Run extra entry point
        self._run_hooks('before_upload')

        # Get list of all files to upload.
        files_in_dist = sorted([
            os.path.join('dist', filename) for filename in os.listdir('dist')]
        )

        # Get servers/repositories.
        servers = self.pypiconfig.distutils_servers()

        register = self.pypiconfig.register_package()
        for server in servers:
            default = True
            exact = False
            if server == 'pypi' and not package_in_pypi(package):
                logger.info("This package does NOT exist yet on PyPI.")
                # We are not yet on pypi.  To avoid an 'Oops...,
                # sorry!' when registering and uploading an internal
                # package we default to False here.
                default = False
                exact = True
            question = "Upload"
            if register:
                question = "Register and upload"
            if utils.ask("%s to %s" % (question, server),
                         default=default, exact=exact):
                if register:
                    logger.info("Registering...")
                    # We only need the first file, it has all the needed info
                    self._retry_twine('register', server, files_in_dist[:1])
                self._retry_twine('upload', server, files_in_dist)

def zester(data):
    main_files = os.listdir(data['workingdir'])
    if 'setup.py' not in main_files and 'setup.cfg' not in main_files:
        return

    from zest.releaser.utils import ask
    if ask("Run pyroma on the package before tagging?"):
        rating = run('directory', os.path.abspath(data['workingdir']))
        if rating < 8:
            if not ask("Continue?"):
                sys.exit(1)

def run_pyroma(data):
    import sys
    from zest.releaser.utils import ask
    if not ask("Run pyroma on the package before uploading?"):
        return
    try:
        from pyroma import run
        result = run(data['tagdir'])
        if result != 10:
            if not ask("Continue?"):
                sys.exit(1)
    except ImportError:
        if not ask("pyroma not available. Continue?"):
            sys.exit(1)

def change_log():
    utils.parse_options()
    utils.configure_logging()
    logger.info('Starting changelogrelease.')
    if not utils.ask("OK to update ChangeLog"):
        return
    if not BUILDOUT:
        logger.warn("No BUILDOUT environment variable")
        return
    vcs = baserelease.Basereleaser().vcs
    package = vcs.name
    buildoutpackage = os.path.split(os.path.abspath(BUILDOUT))[1]
    if package == buildoutpackage:
        logger.warn("It's the buildout")
        return

    # Current buildout
    history_lines, history_encoding = getHistoryLines(vcs)
    headings = extractHeadings(history_lines)
    if not headings:
        return
    changelogs, version = getCurrentChangeLogs(history_lines, headings)

    # Master Buildout
    history_lines, history_encoding = getBuildoutHistoryLines()
    headings = extractHeadings(history_lines)
    if not headings:
        return
    updateBuildoutChangeLogs(history_lines, history_encoding, headings, changelogs, package, version)
    upgradeBuildoutVersion(package, version)

def main():
    logging.basicConfig(level=utils.loglevel(),
                        format="%(levelname)s: %(message)s")
    check_for_files()
    directories = development_eggs()
    if not directories:
        sys.exit()
    old_situation = url_list()
    tags = determine_tags(directories)
    remove_old_part()
    add_new_part(tags)
    new_situation = url_list()
    diff = list(difflib.ndiff(old_situation, new_situation))
    logger.debug("Diff: %s", diff)
    check_stable()

    # XXX The diff is too ugly to put in the history file or the
    # commit message.
    msg = ["Stabilized buildout to most recent svn tags of our packages:"]
    msg += diff
    insert_msg_into_history(msg)
    msg = '\n'.join(msg)

    # show diff, offer commit
    vcs = zest.releaser.choose.version_control()
    diff_cmd = vcs.cmd_diff()
    diff = getoutput(diff_cmd)
    logger.info("The '%s':\n\n%s\n" % (diff_cmd, diff))
    if utils.ask("OK to commit this"):
        commit_cmd = vcs.cmd_commit(msg)
        commit = getoutput(commit_cmd)
        logger.info(commit)

    def _grab_history(self):
        """Calculate the needed history/changelog changes

        Every history heading looks like '1.0 b4 (1972-12-25)'. Extract them,
        check if the first one matches the version and whether it has a the
        current date.
        """
        default_location = None
        config = self.setup_cfg.config
        if config and config.has_option('zest.releaser', 'history_file'):
            default_location = config.get('zest.releaser', 'history_file')
        history_file = self.vcs.history_file(location=default_location)
        if not history_file:
            logger.warn("No history file found")
            self.data['history_lines'] = None
            self.data['history_file'] = None
            self.data['history_encoding'] = None
            return
        logger.debug("Checking %s", history_file)
        history_lines, history_encoding = read_text_file(history_file)
        history_lines = history_lines.split('\n')
        headings = utils.extract_headings_from_history(history_lines)
        if not len(headings):
            logger.error("No detectable version heading in the history "
                         "file %s", history_file)
            sys.exit(1)
        good_heading = self.data['history_header'] % self.data
        # ^^^ history_header is a string with %(abc)s replacements.
        line = headings[0]['line']
        previous = history_lines[line]
        history_lines[line] = good_heading
        logger.debug("Set heading from %r to %r.", previous, good_heading)
        history_lines[line + 1] = utils.fix_rst_heading(
            heading=good_heading,
            below=history_lines[line + 1])
        logger.debug("Set line below heading to %r",
                     history_lines[line + 1])
        self.data['history_lines'] = history_lines
        self.data['history_file'] = history_file
        self.data['history_encoding'] = history_encoding
        # TODO: add line number where an extra changelog entry can be
        # inserted.

        # Look for 'Nothing changed yet' under the latest header.  Not
        # nice if this text ends up in the changelog.  Did nothing happen?
        start = headings[0]['line']
        if len(headings) > 1:
            end = headings[1]['line']
        else:
            end = -1
        for line in history_lines[start:end]:
            if self.data['nothing_changed_yet'] in line:
                if not utils.ask(
                        "WARNING: Changelog contains %r. Are you sure you "
                        "want to release?" % self.data['nothing_changed_yet'],
                        default=False):
                    logger.info("You can use the 'lasttaglog' command to "
                                "see the commits since the last tag.")
                    sys.exit(0)
                break

def show_changelog_entries(data):
    # Find changelog
    # TODO: Figure out how to catch malformed rst
    if data['history_file'] is not None:
        changelog = Changelog(file_location=data['history_file'])
    # Get top release's entry
    entries = changelog.latest()
    if entries is None:
        if not ask("Unable to parse changelog. Continue?", default=True):
            sys.exit()
        return
    print "Changelog entries for version %s." % data['new_version']
    for entry in entries:
        print entry
    if not ask("Continue?", default=True):
        sys.exit()

def compile_in_tag(data):
    """Compile all po files in the tag.

    We expect to get a dictionary from zest.releaser, with a tagdir.

    When an exception occurs during finding/compiling, and we were
    indeed called as an entry point of zest.releaser, we ask the user
    what to do: continue with the release or not.
    """
    tagdir = data.get('tagdir')
    if not tagdir:
        logger.warn("Aborted compiling of po files: no tagdir found in data.")
        return
    logger.info('Finding and compiling po files in %s', tagdir)
    try:
        find_lc_messages(tagdir)
    except Exception:
        logger.warn('Finding and compiling aborted after exception.',
                    exc_info=True)
        if data and ask:
            # We were called as an entry point of zest.releaser.
            if not ask("Error compiling po file.  This could mean some "
                       "languages have no working translations.  Do you want "
                       "to continue with the release?"):
                sys.exit(1)

    def available_tags(self):
        base = self._base_from_svn()
        tags_name = self._tags_name
        if tags_name is None:
            # Suggest to create a tags dir with the default plural /tags name.
            print("tags dir does not exist at %s" % base + 'tags')
            if utils.ask("Shall I create it"):
                cmd = 'svn mkdir %stags -m "Creating tags directory."' % (base)
                logger.info("Running %r", cmd)
                print(execute_command(cmd))
                tags_name = self._tags_name
                assert tags_name == 'tags'
            else:
                sys.exit(0)

        tag_info = execute_command('svn list %s%s' % (base, tags_name))
        network_errors = [
            'Could not resolve hostname',
            'E670008',
            'Repository moved',
            'Unable to connect',
        ]
        found_errors = [1 for network_error in network_errors
                        if network_error in tag_info]
        if found_errors:
            logger.error('Network problem: %s', tag_info)
            sys.exit(1)
        tags = [line.replace('/', '').strip()
                for line in tag_info.split('\n')]
        tags = [tag for tag in tags if tag]  # filter empty ones
        logger.debug("Available tags: %r", tags)
        return tags

    def available_tags(self):
        base = self._base_from_svn()
        tags_name = self._tags_name
        if tags_name is None:
            # Suggest to create a tags dir with the default plural /tags name.
            print "tags dir does not exist at %s" % base + 'tags'
            if utils.ask("Shall I create it"):
                cmd = 'svn mkdir %stags -m "Creating tags directory."' % (base)
                logger.info("Running %r", cmd)
                print system(cmd)
                tags_name = self._tags_name
                assert tags_name == 'tags'
            else:
                sys.exit(0)

        tag_info = system('svn list %s%s' % (base, tags_name))
        if 'Could not resolve hostname' in tag_info or \
                'Repository moved' in tag_info:
            logger.error('Network problem: %s', tag_info)
            sys.exit()
        tags = [line.replace('/', '').strip()
                for line in tag_info.split('\n')]
        tags = [tag for tag in tags if tag]  # filter empty ones
        logger.debug("Available tags: %r", tags)
        return tags

def _run_pyroma(data):   # pragma: no cover
    """Run pyroma (used to perform checks before releasing a new version).
    """
    import sys
    from zest.releaser.utils import ask
    if not ask("Run pyroma on the package before uploading?"):
        return
    try:
        from pyroma import run
        result = run(data['tagdir'])
        if result != 10:
            if not ask("Continue?"):
                sys.exit(1)
    except ImportError:
        if not ask("pyroma not available. Continue?"):
            sys.exit(1)

def cleanup_changelog(data):
    """Cleanup empty headers.

    We call this twice: in prereleaser.before and prereleaser.middle.

    In 'before', we are too early and zest.releaser has not looked for
    the history file yet.  But we try 'CHANGES.rst' ourselves.

    In 'middle' we are a bit too late, as zest.releaser has already
    complained when it found the NOTHING_CHANGED_YET value in the
    history.

    So we call this twice, which should be fine.

    """
    # The history_file is probably not set yet, as we are called too early.
    # That might change subtly in future zest.releaser versions, so let's check
    # it anyway.
    history_file = data.get('history_file')
    if history_file:
        contents = '\n'.join(data['history_lines'])
        encoding = data['history_encoding']
    else:
        # We do not want to copy the logic from zest.releaser that tries to
        # find the history file, but we can check the most obvious spot.
        history_file = 'CHANGES.rst'
        if not os.path.exists(history_file):
            print('Cannot cleanup history, will try again later.')
            return
        contents, encoding = read_text_file(history_file)
    orig_contents = contents
    changed = False
    for header in ALL_HEADERS:
        if header in contents:
            contents = contents.replace(header, '')
            changed = True
    if not changed:
        return
    write_text_file(
        history_file, contents, encoding=encoding)
    print("Cleaned up empty headers from history file {}".format(history_file))
    # Update the data, otherwise our work may get overwritten.
    data['history_lines'] = contents.split('\n')
    if not os.path.isdir('.git'):
        print('Not a git checkout, cannot commit.')
        return
    g = git.Git('.')
    message = "Cleaned up empty headers from changelog.\n\n[ci skip]"
    print(g.diff(history_file))
    msg = "Commit changes?"
    if not ask(msg, default=True):
        # Restore original contents.
        write_text_file(
            history_file, orig_contents, encoding=encoding)
        sys.exit()
    print("Committing changes.")
    print(g.add(history_file))
    print(g.commit(message=message))

def zest_releaser_check(data):
    """Check the completeness of MANIFEST.in before the release.

    This is an entry point for zest.releaser.  See the documentation at
    http://zestreleaser.readthedocs.org/en/latest/entrypoints.html
    """
    from zest.releaser.utils import ask
    if not ask("Do you want to run check-manifest?"):
        return
    try:
        if not check_manifest(data['workingdir']):
            if not ask("MANIFEST.in is not in order. "
                       " Do you want to continue despite that?", default=False):
                sys.exit(1)
    except Failure, e:
        error(e)
        if not ask("Something bad happened. "
                   " Do you want to continue despite that?", default=False):
            sys.exit(2)

def version_control():
    """Return an object that provides the version control interface.

    Base this on the detected version control system.

    We look for .git, .svn, etcetera in the current directory.  We
    might be in a directory a few levels down from the repository
    root.  So if we find nothing here, we go up a few directories.

    As safety valve we use a maximum to avoid an endless loop in case
    there is a logic error.
    """
    path = os.path.abspath(os.curdir)
    q = "You are NOT in the root of the repository. Do you want to go there?"
    for level in range(8):
        curdir_contents = os.listdir(path)
        if '.svn' in curdir_contents:
            # Maybe chdir to the found root.
            if level != 0 and utils.ask(q, default=True):
                os.chdir(path)
            return svn.Subversion(path)
        elif '.hg' in curdir_contents:
            if level != 0 and utils.ask(q, default=True):
                os.chdir(path)
            return hg.Hg(path)
        elif '.bzr' in curdir_contents:
            if level != 0 and utils.ask(q, default=True):
                os.chdir(path)
            return bzr.Bzr(path)
        elif '.git' in curdir_contents:
            if level != 0 and utils.ask(q, default=True):
                os.chdir(path)
            return git.Git(path)
        # Get parent.
        newpath = os.path.abspath(os.path.join(path, os.pardir))
        if newpath == path:
            # We are at the system root.  We cannot go up anymore.
            break
        path = newpath

    logger.critical('No version control system detected.')
    sys.exit(1)

 def _info_if_tag_already_exists(self):
     if self.data['tag_already_exists']:
         # Safety feature.
         version = self.data['version']
         tag = self.data['tag']
         q = ("There is already a tag %s, show "
              "if there are differences?" % version)
         if utils.ask(q):
             diff_command = self.vcs.cmd_diff_last_commit_against_tag(tag)
             print(utils.format_command(diff_command))
             print(execute_command(diff_command))

 def _check_if_tag_already_exists(self):
     """Check if tag already exists and show the difference if so"""
     version = self.data["version"]
     if self.vcs.tag_exists(version):
         self.data["tag_already_exists"] = True
         q = "There is already a tag %s, show " "if there are differences?" % version
         if utils.ask(q):
             diff_command = self.vcs.cmd_diff_last_commit_against_tag(version)
             print(diff_command)
             print(execute_command(diff_command))
     else:
         self.data["tag_already_exists"] = False