diff --git a/src/applications/diviner/markup/DivinerRemarkupRuleSymbol.php b/src/applications/diviner/markup/DivinerRemarkupRuleSymbol.php
index ca395d85c5..1acbaea8d5 100644
--- a/src/applications/diviner/markup/DivinerRemarkupRuleSymbol.php
+++ b/src/applications/diviner/markup/DivinerRemarkupRuleSymbol.php
@@ -1,163 +1,163 @@
 <?php
 
 final class DivinerRemarkupRuleSymbol extends PhutilRemarkupRule {
 
   const KEY_RULE_ATOM_REF = 'rule.diviner.atomref';
 
   public function getPriority() {
     return 200.0;
   }
 
   public function apply($text) {
     // Grammar here is:
     //
     //         rule = '@{' maybe_type name maybe_title '}'
     //   maybe_type = null | type ':' | type '@' book ':'
     //         name = name | name '@' context
     //  maybe_title = null | '|' title
     //
     // So these are all valid:
     //
     //   @{name}
     //   @{type : name}
     //   @{name | title}
     //   @{type @ book : name @ context | title}
 
     return preg_replace_callback(
       '/(?:^|\B)@{'.
         '(?:(?P<type>[^:]+?):)?'.
         '(?P<name>[^}|]+?)'.
         '(?:[|](?P<title>[^}]+))?'.
       '}/',
       array($this, 'markupSymbol'),
       $text);
   }
 
   public function markupSymbol($matches) {
-    if ($this->isFlatText($matches[0])) {
+    if (!$this->isFlatText($matches[0])) {
       return $matches[0];
     }
 
     $type = (string)idx($matches, 'type');
     $name = (string)$matches['name'];
     $title = (string)idx($matches, 'title');
 
     // Collapse sequences of whitespace into a single space.
     $type = preg_replace('/\s+/', ' ', trim($type));
     $name = preg_replace('/\s+/', ' ', trim($name));
     $title = preg_replace('/\s+/', ' ', trim($title));
 
     $ref = array();
 
     if (strpos($type, '@') !== false) {
       list($type, $book) = explode('@', $type, 2);
       $ref['type'] = trim($type);
       $ref['book'] = trim($book);
     } else {
       $ref['type'] = $type;
     }
 
     if (strpos($name, '@') !== false) {
       list($name, $context) = explode('@', $name, 2);
       $ref['name'] = trim($name);
       $ref['context'] = trim($context);
     } else {
       $ref['name'] = $name;
     }
 
     $ref['title'] = nonempty($title, $name);
 
     foreach ($ref as $key => $value) {
       if ($value === '') {
         unset($ref[$key]);
       }
     }
 
     $engine = $this->getEngine();
     $token = $engine->storeText('');
 
     $key = self::KEY_RULE_ATOM_REF;
     $data = $engine->getTextMetadata($key, array());
     $data[$token] = $ref;
     $engine->setTextMetadata($key, $data);
 
     return $token;
   }
 
   public function didMarkupText() {
     $engine = $this->getEngine();
 
     $key = self::KEY_RULE_ATOM_REF;
     $data = $engine->getTextMetadata($key, array());
 
     $renderer = $engine->getConfig('diviner.renderer');
 
     foreach ($data as $token => $ref_dict) {
       $ref = DivinerAtomRef::newFromDictionary($ref_dict);
       $title = $ref->getTitle();
 
       $href = null;
       if ($renderer) {
         // Here, we're generating documentation. If possible, we want to find
         // the real atom ref so we can render the correct default title and
         // render invalid links in an alternate style.
 
         $ref = $renderer->normalizeAtomRef($ref);
         if ($ref) {
           $title = nonempty($ref->getTitle(), $ref->getName());
           $href = $renderer->getHrefForAtomRef($ref);
         }
       } else {
         // Here, we're generating comment text or something like that. Just
         // link to Diviner and let it sort things out.
 
         $href = id(new PhutilURI('/diviner/find/'))
           ->setQueryParams(
             array(
               'book' => $ref->getBook(),
               'name' => $ref->getName(),
               'type' => $ref->getType(),
               'context' => $ref->getContext(),
               'jump' => true,
             ));
       }
 
       // TODO: This probably is not the best place to do this. Move it somewhere
       // better when it becomes more clear where it should actually go.
       if ($ref) {
         switch ($ref->getType()) {
           case 'function':
           case 'method':
             $title = $title.'()';
             break;
         }
       }
 
       if ($this->getEngine()->isTextMode()) {
         if ($href) {
           $link = $title.' <'.PhabricatorEnv::getProductionURI($href).'>';
         } else {
           $link = $title;
         }
       } else if ($href) {
         $link = $this->newTag(
           'a',
           array(
             'class' => 'atom-ref',
             'href' => $href,
           ),
           $title);
       } else {
         $link = $this->newTag(
           'span',
           array(
             'class' => 'atom-ref-invalid',
           ),
           $title);
       }
 
       $engine->overwriteStoredText($token, $link);
     }
   }
 
 }
diff --git a/src/infrastructure/markup/PhabricatorMarkupEngine.php b/src/infrastructure/markup/PhabricatorMarkupEngine.php
index e50a19c566..fac08cbbce 100644
--- a/src/infrastructure/markup/PhabricatorMarkupEngine.php
+++ b/src/infrastructure/markup/PhabricatorMarkupEngine.php
@@ -1,603 +1,603 @@
 <?php
 
 /**
  * Manages markup engine selection, configuration, application, caching and
  * pipelining.
  *
  * @{class:PhabricatorMarkupEngine} can be used to render objects which
  * implement @{interface:PhabricatorMarkupInterface} in a batched, cache-aware
  * way. For example, if you have a list of comments written in remarkup (and
  * the objects implement the correct interface) you can render them by first
  * building an engine and adding the fields with @{method:addObject}.
  *
  *   $field  = 'field:body'; // Field you want to render. Each object exposes
  *                           // one or more fields of markup.
  *
  *   $engine = new PhabricatorMarkupEngine();
  *   foreach ($comments as $comment) {
  *     $engine->addObject($comment, $field);
  *   }
  *
  * Now, call @{method:process} to perform the actual cache/rendering
  * step. This is a heavyweight call which does batched data access and
  * transforms the markup into output.
  *
  *   $engine->process();
  *
  * Finally, do something with the results:
  *
  *   $results = array();
  *   foreach ($comments as $comment) {
  *     $results[] = $engine->getOutput($comment, $field);
  *   }
  *
  * If you have a single object to render, you can use the convenience method
  * @{method:renderOneObject}.
  *
  * @task markup Markup Pipeline
  * @task engine Engine Construction
  */
 final class PhabricatorMarkupEngine {
 
   private $objects = array();
   private $viewer;
-  private $version = 10;
+  private $version = 11;
 
 
 /* -(  Markup Pipeline  )---------------------------------------------------- */
 
 
   /**
    * Convenience method for pushing a single object through the markup
    * pipeline.
    *
    * @param PhabricatorMarkupInterface  The object to render.
    * @param string                      The field to render.
    * @param PhabricatorUser             User viewing the markup.
    * @return string                     Marked up output.
    * @task markup
    */
   public static function renderOneObject(
     PhabricatorMarkupInterface $object,
     $field,
     PhabricatorUser $viewer) {
     return id(new PhabricatorMarkupEngine())
       ->setViewer($viewer)
       ->addObject($object, $field)
       ->process()
       ->getOutput($object, $field);
   }
 
 
   /**
    * Queue an object for markup generation when @{method:process} is
    * called. You can retrieve the output later with @{method:getOutput}.
    *
    * @param PhabricatorMarkupInterface  The object to render.
    * @param string                      The field to render.
    * @return this
    * @task markup
    */
   public function addObject(PhabricatorMarkupInterface $object, $field) {
     $key = $this->getMarkupFieldKey($object, $field);
     $this->objects[$key] = array(
       'object' => $object,
       'field'  => $field,
     );
 
     return $this;
   }
 
 
   /**
    * Process objects queued with @{method:addObject}. You can then retrieve
    * the output with @{method:getOutput}.
    *
    * @return this
    * @task markup
    */
   public function process() {
     $keys = array();
     foreach ($this->objects as $key => $info) {
       if (!isset($info['markup'])) {
         $keys[] = $key;
       }
     }
 
     if (!$keys) {
       return;
     }
 
     $objects = array_select_keys($this->objects, $keys);
 
     // Build all the markup engines. We need an engine for each field whether
     // we have a cache or not, since we still need to postprocess the cache.
     $engines = array();
     foreach ($objects as $key => $info) {
       $engines[$key] = $info['object']->newMarkupEngine($info['field']);
       $engines[$key]->setConfig('viewer', $this->viewer);
     }
 
     // Load or build the preprocessor caches.
     $blocks = $this->loadPreprocessorCaches($engines, $objects);
     $blocks = mpull($blocks, 'getCacheData');
 
     $this->engineCaches = $blocks;
 
     // Finalize the output.
     foreach ($objects as $key => $info) {
       $engine = $engines[$key];
       $field = $info['field'];
       $object = $info['object'];
 
       $output = $engine->postprocessText($blocks[$key]);
       $output = $object->didMarkupText($field, $output, $engine);
       $this->objects[$key]['output'] = $output;
     }
 
     return $this;
   }
 
 
   /**
    * Get the output of markup processing for a field queued with
    * @{method:addObject}. Before you can call this method, you must call
    * @{method:process}.
    *
    * @param PhabricatorMarkupInterface  The object to retrieve.
    * @param string                      The field to retrieve.
    * @return string                     Processed output.
    * @task markup
    */
   public function getOutput(PhabricatorMarkupInterface $object, $field) {
     $key = $this->getMarkupFieldKey($object, $field);
     $this->requireKeyProcessed($key);
 
     return $this->objects[$key]['output'];
   }
 
 
   /**
    * Retrieve engine metadata for a given field.
    *
    * @param PhabricatorMarkupInterface  The object to retrieve.
    * @param string                      The field to retrieve.
    * @param string                      The engine metadata field to retrieve.
    * @param wild                        Optional default value.
    * @task markup
    */
   public function getEngineMetadata(
     PhabricatorMarkupInterface $object,
     $field,
     $metadata_key,
     $default = null) {
 
     $key = $this->getMarkupFieldKey($object, $field);
     $this->requireKeyProcessed($key);
 
     return idx($this->engineCaches[$key]['metadata'], $metadata_key, $default);
   }
 
 
   /**
    * @task markup
    */
   private function requireKeyProcessed($key) {
     if (empty($this->objects[$key])) {
       throw new Exception(
         "Call addObject() before using results (key = '{$key}').");
     }
 
     if (!isset($this->objects[$key]['output'])) {
       throw new Exception(
         'Call process() before using results.');
     }
   }
 
 
   /**
    * @task markup
    */
   private function getMarkupFieldKey(
     PhabricatorMarkupInterface $object,
     $field) {
 
     static $custom;
     if ($custom === null) {
       $custom = array_merge(
         self::loadCustomInlineRules(),
         self::loadCustomBlockRules());
 
       $custom = mpull($custom, 'getRuleVersion', null);
       ksort($custom);
       $custom = PhabricatorHash::digestForIndex(serialize($custom));
     }
 
     return $object->getMarkupFieldKey($field).'@'.$this->version.'@'.$custom;
   }
 
 
   /**
    * @task markup
    */
   private function loadPreprocessorCaches(array $engines, array $objects) {
     $blocks = array();
 
     $use_cache = array();
     foreach ($objects as $key => $info) {
       if ($info['object']->shouldUseMarkupCache($info['field'])) {
         $use_cache[$key] = true;
       }
     }
 
     if ($use_cache) {
       try {
         $blocks = id(new PhabricatorMarkupCache())->loadAllWhere(
           'cacheKey IN (%Ls)',
           array_keys($use_cache));
         $blocks = mpull($blocks, null, 'getCacheKey');
       } catch (Exception $ex) {
         phlog($ex);
       }
     }
 
     foreach ($objects as $key => $info) {
       // False check in case MySQL doesn't support unicode characters
       // in the string (T1191), resulting in unserialize returning false.
       if (isset($blocks[$key]) && $blocks[$key]->getCacheData() !== false) {
         // If we already have a preprocessing cache, we don't need to rebuild
         // it.
         continue;
       }
 
       $text = $info['object']->getMarkupText($info['field']);
       $data = $engines[$key]->preprocessText($text);
 
       // NOTE: This is just debugging information to help sort out cache issues.
       // If one machine is misconfigured and poisoning caches you can use this
       // field to hunt it down.
 
       $metadata = array(
         'host' => php_uname('n'),
       );
 
       $blocks[$key] = id(new PhabricatorMarkupCache())
         ->setCacheKey($key)
         ->setCacheData($data)
         ->setMetadata($metadata);
 
       if (isset($use_cache[$key])) {
         // This is just filling a cache and always safe, even on a read pathway.
         $unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
           $blocks[$key]->replace();
         unset($unguarded);
       }
     }
 
     return $blocks;
   }
 
 
   /**
    * Set the viewing user. Used to implement object permissions.
    *
    * @param PhabricatorUser The viewing user.
    * @return this
    * @task markup
    */
   public function setViewer(PhabricatorUser $viewer) {
     $this->viewer = $viewer;
     return $this;
   }
 
 
 /* -(  Engine Construction  )------------------------------------------------ */
 
 
 
   /**
    * @task engine
    */
   public static function newManiphestMarkupEngine() {
     return self::newMarkupEngine(array(
     ));
   }
 
 
   /**
    * @task engine
    */
   public static function newPhrictionMarkupEngine() {
     return self::newMarkupEngine(array(
       'header.generate-toc' => true,
     ));
   }
 
 
   /**
    * @task engine
    */
   public static function newPhameMarkupEngine() {
     return self::newMarkupEngine(array(
       'macros' => false,
     ));
   }
 
 
   /**
    * @task engine
    */
   public static function newFeedMarkupEngine() {
     return self::newMarkupEngine(
       array(
         'macros'      => false,
         'youtube'     => false,
 
       ));
   }
 
 
   /**
    * @task engine
    */
   public static function newDifferentialMarkupEngine(array $options = array()) {
     return self::newMarkupEngine(array(
       'differential.diff' => idx($options, 'differential.diff'),
     ));
   }
 
 
   /**
    * @task engine
    */
   public static function newDiffusionMarkupEngine(array $options = array()) {
     return self::newMarkupEngine(array(
       'header.generate-toc' => true,
     ));
   }
 
   /**
    * @task engine
    */
   public static function getEngine($ruleset = 'default') {
     static $engines = array();
     if (isset($engines[$ruleset])) {
       return $engines[$ruleset];
     }
 
     $engine = null;
     switch ($ruleset) {
       case 'default':
         $engine = self::newMarkupEngine(array());
         break;
       case 'nolinebreaks':
         $engine = self::newMarkupEngine(array());
         $engine->setConfig('preserve-linebreaks', false);
         break;
       case 'diffusion-readme':
         $engine = self::newMarkupEngine(array());
         $engine->setConfig('preserve-linebreaks', false);
         $engine->setConfig('header.generate-toc', true);
         break;
       case 'diviner':
         $engine = self::newMarkupEngine(array());
         $engine->setConfig('preserve-linebreaks', false);
   //    $engine->setConfig('diviner.renderer', new DivinerDefaultRenderer());
         $engine->setConfig('header.generate-toc', true);
         break;
       case 'extract':
         // Engine used for reference/edge extraction. Turn off anything which
         // is slow and doesn't change reference extraction.
         $engine = self::newMarkupEngine(array());
         $engine->setConfig('pygments.enabled', false);
         break;
       default:
         throw new Exception("Unknown engine ruleset: {$ruleset}!");
     }
 
     $engines[$ruleset] = $engine;
     return $engine;
   }
 
   /**
    * @task engine
    */
   private static function getMarkupEngineDefaultConfiguration() {
     return array(
       'pygments'      => PhabricatorEnv::getEnvConfig('pygments.enabled'),
       'youtube'       => PhabricatorEnv::getEnvConfig(
         'remarkup.enable-embedded-youtube'),
       'differential.diff' => null,
       'header.generate-toc' => false,
       'macros'        => true,
       'uri.allowed-protocols' => PhabricatorEnv::getEnvConfig(
         'uri.allowed-protocols'),
       'syntax-highlighter.engine' => PhabricatorEnv::getEnvConfig(
         'syntax-highlighter.engine'),
       'preserve-linebreaks' => true,
     );
   }
 
 
   /**
    * @task engine
    */
   public static function newMarkupEngine(array $options) {
 
     $options += self::getMarkupEngineDefaultConfiguration();
 
     $engine = new PhutilRemarkupEngine();
 
     $engine->setConfig('preserve-linebreaks', $options['preserve-linebreaks']);
     $engine->setConfig('pygments.enabled', $options['pygments']);
     $engine->setConfig(
       'uri.allowed-protocols',
       $options['uri.allowed-protocols']);
     $engine->setConfig('differential.diff', $options['differential.diff']);
     $engine->setConfig('header.generate-toc', $options['header.generate-toc']);
     $engine->setConfig(
       'syntax-highlighter.engine',
       $options['syntax-highlighter.engine']);
 
     $rules = array();
     $rules[] = new PhutilRemarkupRuleEscapeRemarkup();
     $rules[] = new PhutilRemarkupRuleMonospace();
 
 
     $rules[] = new PhutilRemarkupRuleDocumentLink();
 
     if ($options['youtube']) {
       $rules[] = new PhabricatorRemarkupRuleYoutube();
     }
 
     $applications = PhabricatorApplication::getAllInstalledApplications();
     foreach ($applications as $application) {
       foreach ($application->getRemarkupRules() as $rule) {
         $rules[] = $rule;
       }
     }
 
     $rules[] = new PhutilRemarkupRuleHyperlink();
 
     if ($options['macros']) {
       $rules[] = new PhabricatorRemarkupRuleImageMacro();
       $rules[] = new PhabricatorRemarkupRuleMeme();
     }
 
     $rules[] = new PhutilRemarkupRuleBold();
     $rules[] = new PhutilRemarkupRuleItalic();
     $rules[] = new PhutilRemarkupRuleDel();
     $rules[] = new PhutilRemarkupRuleUnderline();
 
     foreach (self::loadCustomInlineRules() as $rule) {
       $rules[] = $rule;
     }
 
     $blocks = array();
     $blocks[] = new PhutilRemarkupEngineRemarkupQuotesBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupReplyBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupLiteralBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupHeaderBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupHorizontalRuleBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupListBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupCodeBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupNoteBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupTableBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupSimpleTableBlockRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupInterpreterRule();
     $blocks[] = new PhutilRemarkupEngineRemarkupDefaultBlockRule();
 
     foreach (self::loadCustomBlockRules() as $rule) {
       $blocks[] = $rule;
     }
 
     foreach ($blocks as $block) {
       $block->setMarkupRules($rules);
     }
 
     $engine->setBlockRules($blocks);
 
     return $engine;
   }
 
   public static function extractPHIDsFromMentions(
     PhabricatorUser $viewer,
     array $content_blocks) {
 
     $mentions = array();
 
     $engine = self::newDifferentialMarkupEngine();
     $engine->setConfig('viewer', $viewer);
 
     foreach ($content_blocks as $content_block) {
       $engine->markupText($content_block);
       $phids = $engine->getTextMetadata(
         PhabricatorRemarkupRuleMention::KEY_MENTIONED,
         array());
       $mentions += $phids;
     }
 
     return $mentions;
   }
 
   public static function extractFilePHIDsFromEmbeddedFiles(
     PhabricatorUser $viewer,
     array $content_blocks) {
     $files = array();
 
     $engine = self::newDifferentialMarkupEngine();
     $engine->setConfig('viewer', $viewer);
 
     foreach ($content_blocks as $content_block) {
       $engine->markupText($content_block);
       $ids = $engine->getTextMetadata(
         PhabricatorRemarkupRuleEmbedFile::KEY_EMBED_FILE_PHIDS,
         array());
       $files += $ids;
     }
 
     return $files;
   }
 
   /**
    * Produce a corpus summary, in a way that shortens the underlying text
    * without truncating it somewhere awkward.
    *
    * TODO: We could do a better job of this.
    *
    * @param string  Remarkup corpus to summarize.
    * @return string Summarized corpus.
    */
   public static function summarize($corpus) {
 
     // Major goals here are:
     //  - Don't split in the middle of a character (utf-8).
     //  - Don't split in the middle of, e.g., **bold** text, since
     //    we end up with hanging '**' in the summary.
     //  - Try not to pick an image macro, header, embedded file, etc.
     //  - Hopefully don't return too much text. We don't explicitly limit
     //    this right now.
 
     $blocks = preg_split("/\n *\n\s*/", trim($corpus));
 
     $best = null;
     foreach ($blocks as $block) {
       // This is a test for normal spaces in the block, i.e. a heuristic to
       // distinguish standard paragraphs from things like image macros. It may
       // not work well for non-latin text. We prefer to summarize with a
       // paragraph of normal words over an image macro, if possible.
       $has_space = preg_match('/\w\s\w/', $block);
 
       // This is a test to find embedded images and headers. We prefer to
       // summarize with a normal paragraph over a header or an embedded object,
       // if possible.
       $has_embed = preg_match('/^[{=]/', $block);
 
       if ($has_space && !$has_embed) {
         // This seems like a good summary, so return it.
         return $block;
       }
 
       if (!$best) {
         // This is the first block we found; if everything is garbage just
         // use the first block.
         $best = $block;
       }
     }
 
     return $best;
   }
 
   private static function loadCustomInlineRules() {
     return id(new PhutilSymbolLoader())
       ->setAncestorClass('PhabricatorRemarkupCustomInlineRule')
       ->loadObjects();
   }
 
   private static function loadCustomBlockRules() {
     return id(new PhutilSymbolLoader())
       ->setAncestorClass('PhabricatorRemarkupCustomBlockRule')
       ->loadObjects();
   }
 
 }