public function parseCommit(PhabricatorRepository $repository, PhabricatorRepositoryCommit $commit)
    {
        $data = id(new PhabricatorRepositoryCommitData())->loadOneWhere('commitID = %d', $commit->getID());
        if (!$data) {
            // TODO: Permanent failure.
            return;
        }
        $rules = HeraldRule::loadAllByContentTypeWithFullData(HeraldContentTypeConfig::CONTENT_TYPE_COMMIT, $commit->getPHID());
        $adapter = new HeraldCommitAdapter($repository, $commit, $data);
        $engine = new HeraldEngine();
        $effects = $engine->applyRules($rules, $adapter);
        $engine->applyEffects($effects, $adapter, $rules);
        $audit_phids = $adapter->getAuditMap();
        if ($audit_phids) {
            $this->createAudits($commit, $audit_phids, $rules);
        }
        $this->createAuditsFromCommitMessage($commit, $data);
        $email_phids = $adapter->getEmailPHIDs();
        if (!$email_phids) {
            return;
        }
        if ($repository->getDetail('herald-disabled')) {
            // This just means "disable email"; audits are (mostly) idempotent.
            return;
        }
        $xscript = $engine->getTranscript();
        $revision = $adapter->loadDifferentialRevision();
        if ($revision) {
            $name = $revision->getTitle();
        } else {
            $name = $data->getSummary();
        }
        $author_phid = $data->getCommitDetail('authorPHID');
        $reviewer_phid = $data->getCommitDetail('reviewerPHID');
        $phids = array_filter(array($author_phid, $reviewer_phid, $commit->getPHID()));
        $handles = id(new PhabricatorObjectHandleData($phids))->loadHandles();
        $commit_handle = $handles[$commit->getPHID()];
        $commit_name = $commit_handle->getName();
        if ($author_phid) {
            $author_name = $handles[$author_phid]->getName();
        } else {
            $author_name = $data->getAuthorName();
        }
        if ($reviewer_phid) {
            $reviewer_name = $handles[$reviewer_phid]->getName();
        } else {
            $reviewer_name = null;
        }
        $who = implode(', ', array_filter(array($author_name, $reviewer_name)));
        $description = $data->getCommitMessage();
        $commit_uri = PhabricatorEnv::getProductionURI($commit_handle->getURI());
        $differential = $revision ? PhabricatorEnv::getProductionURI('/D' . $revision->getID()) : 'No revision.';
        $files = $adapter->loadAffectedPaths();
        sort($files);
        $files = implode("\n  ", $files);
        $xscript_id = $xscript->getID();
        $manage_uri = PhabricatorEnv::getProductionURI('/herald/view/commits/');
        $why_uri = PhabricatorEnv::getProductionURI('/herald/transcript/' . $xscript_id . '/');
        $reply_handler = PhabricatorAuditCommentEditor::newReplyHandlerForCommit($commit);
        $reply_instructions = $reply_handler->getReplyHandlerInstructions();
        if ($reply_instructions) {
            $reply_instructions = "\n" . "REPLY HANDLER ACTIONS\n" . "  " . $reply_instructions . "\n";
        }
        $body = <<<EOBODY
DESCRIPTION
{$description}

DETAILS
  {$commit_uri}

DIFFERENTIAL REVISION
  {$differential}

AFFECTED FILES
  {$files}
{$reply_instructions}
MANAGE HERALD COMMIT RULES
  {$manage_uri}

WHY DID I GET THIS EMAIL?
  {$why_uri}

EOBODY;
        $prefix = PhabricatorEnv::getEnvConfig('metamta.diffusion.subject-prefix');
        $subject = trim("{$prefix} {$commit_name}: {$name}");
        $vary_subject = trim("{$prefix} [Commit] {$commit_name}: {$name}");
        $threading = PhabricatorAuditCommentEditor::getMailThreading($commit->getPHID());
        list($thread_id, $thread_topic) = $threading;
        $template = new PhabricatorMetaMTAMail();
        $template->setRelatedPHID($commit->getPHID());
        $template->setSubject($subject);
        $template->setVarySubject($subject);
        $template->setBody($body);
        $template->setThreadID($thread_id, $is_new = true);
        $template->addHeader('Thread-Topic', $thread_topic);
        $template->setIsBulk(true);
        $template->addHeader('X-Herald-Rules', $xscript->getXHeraldRulesHeader());
        if ($author_phid) {
            $template->setFrom($author_phid);
        }
        $mails = $reply_handler->multiplexMail($template, id(new PhabricatorObjectHandleData($email_phids))->loadHandles(), array());
        foreach ($mails as $mail) {
            $mail->saveAndSend();
        }
    }