def parent_commits(self, commit):
        logger.info('DEPLOY_DEBUG: iterating through parent commits...')
        p_commits = []
        for p in commit['object'].parents:
            # skip parent if it in database
            if TicketCommit.objects.filter(commit_hash=p.hexsha).exists():
                logger.info('DEPLOY_DEBUG: %s already in DB, skipped' %
                            p.hexsha)
                continue
            p_commit = commit.copy()
            p_commit.update({
                'object': p,
                'who': '%s <%s>' % (p.author.name, p.author.email),
                'comment': p.summary,
                'revision': p.hexsha,
            })
            p_commit['diff'] = ''
            p_commits.append(p_commit)
            return p_commits

    def process_commit(self, commit):
        """
        Process git commit

        Commit: dict with fields:
            'who': author
            'comment': comment
            'revision': commit hash
            'branch': commit branch
            'diff': merge diff
            'commit_time': commit datetime
            'deploy_result': deployment result
        """
        commits = []
        p_commits = self.parent_commits(commit)
        commits.append(commit)
        commits.append(p_commits)

        for commit in commits:
            if commit.get('object'):
                commit['commit_time'] = datetime.datetime.fromtimestamp(
                    commit['object'].committed_date
                )

            logger.info('DEPLOY_DEBUG (%s): Incoming task' %
                        commit.get('revision'))

            commit_message = CommitProcessor.get_commit_message(
                commit.get('comment'))
            logger.debug('DEPLOY_DEBUG (%s): commit_message %s' %
                         (commit.get('revision'), unicode(commit_message)))

            # get ticket
            ticket = Ticket.get_instance(self.project,
                                         commit_message.get('ticket_id'))
            if not ticket:
                error_msg = 'Ticket %s does not exist in Kavyarnya.' % \
                            commit_message.get('ticket_id', '<unknown>')
                self.parse_error(self.project, commit, self.pdc, error_msg)
                errors = {
                    'ticket': [error_msg],
                    'project': commit.get('project'),
                }
                logger.debug('DEPLOY_DEBUG (%s): %s' %
                             (commit.get('revision'), unicode(errors)))
                return errors

            logger.info('DEPLOY_DEBUG (%s): ticket is %s' %
                        (commit.get('revision'), unicode(ticket)))

            # push to master
            if commit.get('branch') == 'master':
                self.integration(ticket, commit)

            # defect merged
            if 'Merge' in commit_message['message_label'] and \
                    ticket.type == 'defect':
                self.merge(commit, ticket, commit_message)

            self.get_trac_message(ticket, commit)

        return None