diff --git a/src/applications/differential/mail/DifferentialInlineCommentMailView.php b/src/applications/differential/mail/DifferentialInlineCommentMailView.php
index 8b28b29c99..4c6dd5ea8b 100644
--- a/src/applications/differential/mail/DifferentialInlineCommentMailView.php
+++ b/src/applications/differential/mail/DifferentialInlineCommentMailView.php
@@ -1,424 +1,445 @@
 <?php
 
 final class DifferentialInlineCommentMailView
   extends Phobject {
 
   private $viewer;
   private $inlines;
   private $changesets;
   private $authors;
 
   public function setViewer(PhabricatorUser $viewer) {
     $this->viewer = $viewer;
     return $this;
   }
 
   public function getViewer() {
     return $this->viewer;
   }
 
   public function setInlines($inlines) {
     $this->inlines = $inlines;
     return $this;
   }
 
   public function getInlines() {
     return $this->inlines;
   }
 
   public function buildMailSection() {
     $inlines = $this->getInlines();
 
     $comments = mpull($inlines, 'getComment');
     $comments = mpull($comments, null, 'getPHID');
     $parents = $this->loadParents($comments);
     $all_comments = $comments + $parents;
 
     $this->changesets = $this->loadChangesets($all_comments);
     $this->authors = $this->loadAuthors($all_comments);
     $groups = $this->groupInlines($inlines);
 
     $hunk_parser = new DifferentialHunkParser();
 
     $spacer_text = null;
     $spacer_html = phutil_tag('br');
 
     $section = new PhabricatorMetaMTAMailSection();
 
     $last_group_key = last_key($groups);
     foreach ($groups as $changeset_id => $group) {
       $changeset = $this->getChangeset($changeset_id);
       if (!$changeset) {
         continue;
       }
 
       $is_last_group = ($changeset_id == $last_group_key);
 
       $last_inline_key = last_key($group);
       foreach ($group as $inline_key => $inline) {
         $comment = $inline->getComment();
         $parent_phid = $comment->getReplyToCommentPHID();
 
         $is_last_inline = ($inline_key == $last_inline_key);
 
         $context_text = null;
         $context_html = null;
 
         if ($parent_phid) {
           $parent = idx($parents, $parent_phid);
           if ($parent) {
             $context_text = $this->renderInline($parent, false, true);
             $context_html = $this->renderInline($parent, true, true);
           }
         } else {
           $patch_text = $this->getPatch($hunk_parser, $comment, false);
           $context_text = $this->renderPatch($comment, $patch_text, false);
 
           $patch_html = $this->getPatch($hunk_parser, $comment, true);
           $context_html = $this->renderPatch($comment, $patch_html, true);
         }
 
         $render_text = $this->renderInline($comment, false, false);
         $render_html = $this->renderInline($comment, true, false);
 
         $section->addPlaintextFragment($context_text);
         $section->addHTMLFragment($context_html);
 
         $section->addPlaintextFragment($spacer_text);
 
         $section->addPlaintextFragment($render_text);
         $section->addHTMLFragment($render_html);
 
         if (!$is_last_group || !$is_last_inline) {
           $section->addPlaintextFragment($spacer_text);
           $section->addHTMLFragment($spacer_html);
         }
       }
     }
 
     return $section;
   }
 
   private function loadChangesets(array $comments) {
     if (!$comments) {
       return array();
     }
 
     $ids = array();
     foreach ($comments as $comment) {
       $ids[] = $comment->getChangesetID();
     }
 
     $changesets = id(new DifferentialChangesetQuery())
       ->setViewer($this->getViewer())
       ->withIDs($ids)
       ->needHunks(true)
       ->execute();
 
     return mpull($changesets, null, 'getID');
   }
 
   private function loadParents(array $comments) {
     $viewer = $this->getViewer();
 
     $phids = array();
     foreach ($comments as $comment) {
       $parent_phid = $comment->getReplyToCommentPHID();
       if (!$parent_phid) {
         continue;
       }
       $phids[] = $parent_phid;
     }
 
     if (!$phids) {
       return array();
     }
 
     $parents = id(new DifferentialDiffInlineCommentQuery())
       ->setViewer($viewer)
       ->withPHIDs($phids)
       ->execute();
 
     return mpull($parents, null, 'getPHID');
   }
 
   private function loadAuthors(array $comments) {
     $viewer = $this->getViewer();
 
     $phids = array();
     foreach ($comments as $comment) {
       $author_phid = $comment->getAuthorPHID();
       if (!$author_phid) {
         continue;
       }
       $phids[] = $author_phid;
     }
 
     if (!$phids) {
       return array();
     }
 
     return $viewer->loadHandles($phids);
   }
 
   private function groupInlines(array $inlines) {
     return DifferentialTransactionComment::sortAndGroupInlines(
       $inlines,
       $this->changesets);
   }
 
   private function renderInline(
     DifferentialTransactionComment $comment,
     $is_html,
     $is_quote) {
 
     $changeset = $this->getChangeset($comment->getChangesetID());
     if (!$changeset) {
       return null;
     }
 
     $content = $comment->getContent();
     $content = $this->renderRemarkupContent($content, $is_html);
 
     if ($is_quote) {
       if ($is_html) {
         $style = array(
           'padding: 4px 0;',
         );
 
         $content = phutil_tag(
           'div',
           array(
             'style' => implode(' ', $style),
           ),
           $content);
       }
       $header = $this->renderHeader($comment, $is_html, true);
     } else {
       $header = null;
     }
 
     $parts = array(
       $header,
       "\n",
       $content,
     );
 
     if (!$is_html) {
       $parts = implode('', $parts);
       $parts = trim($parts);
     }
 
     if ($is_quote) {
       if ($is_html) {
         $parts = $this->quoteHTML($parts);
       } else {
         $parts = $this->quoteText($parts);
       }
     }
 
     return $parts;
   }
 
   private function renderRemarkupContent($content, $is_html) {
     $viewer = $this->getViewer();
     $production_uri = PhabricatorEnv::getProductionURI('/');
 
     if ($is_html) {
       $mode = PhutilRemarkupEngine::MODE_HTML_MAIL;
     } else {
       $mode = PhutilRemarkupEngine::MODE_TEXT;
     }
 
     $engine = PhabricatorMarkupEngine::newMarkupEngine(array())
       ->setConfig('viewer', $viewer)
       ->setConfig('uri.base', $production_uri)
       ->setMode($mode);
 
     try {
       return $engine->markupText($content);
     } catch (Exception $ex) {
       return $content;
     }
   }
 
   private function getChangeset($id) {
     return idx($this->changesets, $id);
   }
 
   private function getAuthor($phid) {
     if (isset($this->authors[$phid])) {
       return $this->authors[$phid];
     }
     return null;
   }
 
   private function quoteText($block) {
     $block = phutil_split_lines($block);
     foreach ($block as $key => $line) {
       $block[$key] = '> '.$line;
     }
 
     return implode('', $block);
   }
 
   private function quoteHTML($block) {
     $styles = array(
       'padding: 4px 8px;',
       'background: #F8F9FC;',
       'border-left: 3px solid #a7b5bf;',
       'margin: 4px 0 0;',
     );
 
     $styles = implode(' ', $styles);
 
     return phutil_tag(
       'div',
       array(
         'style' => $styles,
       ),
       $block);
   }
 
   private function getPatch(
     DifferentialHunkParser $parser,
     DifferentialTransactionComment $comment,
     $is_html) {
 
     $changeset = $this->getChangeset($comment->getChangesetID());
     $is_new = $comment->getIsNewFile();
     $start = $comment->getLineNumber();
     $length = $comment->getLineLength();
 
+    // By default, show one line of context around the target inline.
+    $context = 1;
+
+    // If the inline is at least 3 lines long, don't show any extra context.
+    if ($length >= 2) {
+      $context = 0;
+    }
+
+    // If the inline is more than 7 lines long, only show the first 7 lines.
+    if ($length >= 6) {
+      $length = 6;
+    }
+
     if (!$is_html) {
       $hunks = $changeset->getHunks();
-      $patch = $parser->makeContextDiff($hunks, $is_new, $start, $length, 1);
+      $patch = $parser->makeContextDiff(
+        $hunks,
+        $is_new,
+        $start,
+        $length,
+        $context);
       $patch = phutil_split_lines($patch);
 
       // Remove the "@@ -x,y +u,v @@" line.
       array_shift($patch);
 
       return implode('', $patch);
     }
 
     $viewer = $this->getViewer();
     $engine = new PhabricatorMarkupEngine();
 
     if ($is_new) {
       $offset_mode = 'new';
     } else {
       $offset_mode = 'old';
     }
 
     $parser = id(new DifferentialChangesetParser())
       ->setUser($viewer)
       ->setChangeset($changeset)
       ->setOffsetMode($offset_mode)
       ->setMarkupEngine($engine);
 
     $parser->setRenderer(new DifferentialChangesetOneUpMailRenderer());
 
-    return $parser->render($start - 1, $length + 3, array());
+    return $parser->render(
+      $start - $context,
+      $length + 1 + (2 * $context),
+      array());
   }
 
   private function renderPatch(
     DifferentialTransactionComment $comment,
     $patch,
     $is_html) {
 
     if ($is_html) {
       $style = array(
         'font: 11px/15px "Menlo", "Consolas", "Monaco", monospace;',
         'padding: 4px 0;',
         'margin: 0;',
       );
 
       $style = implode(' ', $style);
       $patch = phutil_tag(
         'pre',
         array(
           'style' => $style,
         ),
         $patch);
     }
 
     $header = $this->renderHeader($comment, $is_html, false);
 
     $patch = array(
       $header,
       "\n",
       $patch,
     );
 
     if (!$is_html) {
       $patch = implode('', $patch);
       $patch = $this->quoteText($patch);
     } else {
       $patch = $this->quoteHTML($patch);
     }
 
     return $patch;
   }
 
   private function renderHeader(
     DifferentialTransactionComment $comment,
     $is_html,
     $with_author) {
 
     $changeset = $this->getChangeset($comment->getChangesetID());
     $path = $changeset->getFilename();
 
     $start = $comment->getLineNumber();
     $length = $comment->getLineLength();
     if ($length) {
       $range = pht('%s-%s', $start, $start + $length);
     } else {
       $range = $start;
     }
 
     $header = "{$path}:{$range}";
     if ($is_html) {
       $header = phutil_tag(
         'span',
         array(
           'style' => 'color: #000000',
         ),
         $header);
     }
 
     if ($with_author) {
       $author = $this->getAuthor($comment->getAuthorPHID());
     } else {
       $author = null;
     }
 
     if ($author) {
       $byline = '@'.$author->getName();
 
       if ($is_html) {
         $byline = phutil_tag(
           'span',
           array(
             'style' => 'color: #000000',
           ),
           $byline);
       }
 
       $header = pht('%s wrote in %s', $byline, $header);
     } else {
       $header = pht('In %s', $header);
     }
 
     if ($is_html) {
       $header = phutil_tag(
         'div',
         array(
           'style' => 'font-style: italic; color: #74777d',
         ),
         $header);
     }
 
     return $header;
   }
 
 }
diff --git a/src/applications/differential/parser/DifferentialChangesetParser.php b/src/applications/differential/parser/DifferentialChangesetParser.php
index ef45896081..f7815538ac 100644
--- a/src/applications/differential/parser/DifferentialChangesetParser.php
+++ b/src/applications/differential/parser/DifferentialChangesetParser.php
@@ -1,1678 +1,1678 @@
 <?php
 
 final class DifferentialChangesetParser extends Phobject {
 
   const HIGHLIGHT_BYTE_LIMIT = 262144;
 
   protected $visible      = array();
   protected $new          = array();
   protected $old          = array();
   protected $intra        = array();
   protected $newRender    = null;
   protected $oldRender    = null;
 
   protected $filename     = null;
   protected $hunkStartLines = array();
 
   protected $comments     = array();
   protected $specialAttributes = array();
 
   protected $changeset;
   protected $whitespaceMode = null;
 
   protected $renderCacheKey = null;
 
   private $handles = array();
   private $user;
 
   private $leftSideChangesetID;
   private $leftSideAttachesToNewFile;
 
   private $rightSideChangesetID;
   private $rightSideAttachesToNewFile;
 
   private $originalLeft;
   private $originalRight;
 
   private $renderingReference;
   private $isSubparser;
 
   private $isTopLevel;
 
   private $coverage;
   private $markupEngine;
   private $highlightErrors;
   private $disableCache;
   private $renderer;
   private $characterEncoding;
   private $highlightAs;
   private $highlightingDisabled;
   private $showEditAndReplyLinks = true;
   private $canMarkDone;
   private $objectOwnerPHID;
   private $offsetMode;
 
   private $rangeStart;
   private $rangeEnd;
   private $mask;
 
   private $highlightEngine;
 
   public function setRange($start, $end) {
     $this->rangeStart = $start;
     $this->rangeEnd = $end;
     return $this;
   }
 
   public function setMask(array $mask) {
     $this->mask = $mask;
     return $this;
   }
 
   public function renderChangeset() {
     return $this->render($this->rangeStart, $this->rangeEnd, $this->mask);
   }
 
   public function setShowEditAndReplyLinks($bool) {
     $this->showEditAndReplyLinks = $bool;
     return $this;
   }
 
   public function getShowEditAndReplyLinks() {
     return $this->showEditAndReplyLinks;
   }
 
   public function setHighlightAs($highlight_as) {
     $this->highlightAs = $highlight_as;
     return $this;
   }
 
   public function getHighlightAs() {
     return $this->highlightAs;
   }
 
   public function setCharacterEncoding($character_encoding) {
     $this->characterEncoding = $character_encoding;
     return $this;
   }
 
   public function getCharacterEncoding() {
     return $this->characterEncoding;
   }
 
   public function setRenderer(DifferentialChangesetRenderer $renderer) {
     $this->renderer = $renderer;
     return $this;
   }
 
   public function getRenderer() {
     if (!$this->renderer) {
       return new DifferentialChangesetTwoUpRenderer();
     }
     return $this->renderer;
   }
 
   public function setDisableCache($disable_cache) {
     $this->disableCache = $disable_cache;
     return $this;
   }
 
   public function getDisableCache() {
     return $this->disableCache;
   }
 
   public function setCanMarkDone($can_mark_done) {
     $this->canMarkDone = $can_mark_done;
     return $this;
   }
 
   public function getCanMarkDone() {
     return $this->canMarkDone;
   }
 
   public function setObjectOwnerPHID($phid) {
     $this->objectOwnerPHID = $phid;
     return $this;
   }
 
   public function getObjectOwnerPHID() {
     return $this->objectOwnerPHID;
   }
 
   public function setOffsetMode($offset_mode) {
     $this->offsetMode = $offset_mode;
     return $this;
   }
 
   public function getOffsetMode() {
     return $this->offsetMode;
   }
 
   public static function getDefaultRendererForViewer(PhabricatorUser $viewer) {
     $prefs = $viewer->loadPreferences();
     $pref_unified = PhabricatorUserPreferences::PREFERENCE_DIFF_UNIFIED;
     if ($prefs->getPreference($pref_unified) == 'unified') {
       return '1up';
     }
     return null;
   }
 
   public function readParametersFromRequest(AphrontRequest $request) {
     $this->setWhitespaceMode($request->getStr('whitespace'));
     $this->setCharacterEncoding($request->getStr('encoding'));
     $this->setHighlightAs($request->getStr('highlight'));
 
     $renderer = null;
 
     // If the viewer prefers unified diffs, always set the renderer to unified.
     // Otherwise, we leave it unspecified and the client will choose a
     // renderer based on the screen size.
 
     if ($request->getStr('renderer')) {
       $renderer = $request->getStr('renderer');
     } else {
       $renderer = self::getDefaultRendererForViewer($request->getViewer());
     }
 
     switch ($renderer) {
       case '1up':
         $this->setRenderer(new DifferentialChangesetOneUpRenderer());
         break;
       default:
         $this->setRenderer(new DifferentialChangesetTwoUpRenderer());
         break;
     }
 
     return $this;
   }
 
   const CACHE_VERSION = 11;
   const CACHE_MAX_SIZE = 8e6;
 
   const ATTR_GENERATED  = 'attr:generated';
   const ATTR_DELETED    = 'attr:deleted';
   const ATTR_UNCHANGED  = 'attr:unchanged';
   const ATTR_WHITELINES = 'attr:white';
   const ATTR_MOVEAWAY   = 'attr:moveaway';
 
   const LINES_CONTEXT = 8;
 
   const WHITESPACE_SHOW_ALL         = 'show-all';
   const WHITESPACE_IGNORE_TRAILING  = 'ignore-trailing';
   const WHITESPACE_IGNORE_MOST      = 'ignore-most';
   const WHITESPACE_IGNORE_ALL       = 'ignore-all';
 
   public function setOldLines(array $lines) {
     $this->old = $lines;
     return $this;
   }
 
   public function setNewLines(array $lines) {
     $this->new = $lines;
     return $this;
   }
 
   public function setSpecialAttributes(array $attributes) {
     $this->specialAttributes = $attributes;
     return $this;
   }
 
   public function setIntraLineDiffs(array $diffs) {
     $this->intra = $diffs;
     return $this;
   }
 
   public function setVisibileLinesMask(array $mask) {
     $this->visible = $mask;
     return $this;
   }
 
   /**
    * Configure which Changeset comments added to the right side of the visible
    * diff will be attached to. The ID must be the ID of a real Differential
    * Changeset.
    *
    * The complexity here is that we may show an arbitrary side of an arbitrary
    * changeset as either the left or right part of a diff. This method allows
    * the left and right halves of the displayed diff to be correctly mapped to
    * storage changesets.
    *
    * @param id    The Differential Changeset ID that comments added to the right
    *              side of the visible diff should be attached to.
    * @param bool  If true, attach new comments to the right side of the storage
    *              changeset. Note that this may be false, if the left side of
    *              some storage changeset is being shown as the right side of
    *              a display diff.
    * @return this
    */
   public function setRightSideCommentMapping($id, $is_new) {
     $this->rightSideChangesetID = $id;
     $this->rightSideAttachesToNewFile = $is_new;
     return $this;
   }
 
   /**
    * See setRightSideCommentMapping(), but this sets information for the left
    * side of the display diff.
    */
   public function setLeftSideCommentMapping($id, $is_new) {
     $this->leftSideChangesetID = $id;
     $this->leftSideAttachesToNewFile = $is_new;
     return $this;
   }
 
   public function setOriginals(
     DifferentialChangeset $left,
     DifferentialChangeset $right) {
 
     $this->originalLeft = $left;
     $this->originalRight = $right;
     return $this;
   }
 
   public function diffOriginals() {
     $engine = new PhabricatorDifferenceEngine();
     $changeset = $engine->generateChangesetFromFileContent(
       implode('', mpull($this->originalLeft->getHunks(), 'getChanges')),
       implode('', mpull($this->originalRight->getHunks(), 'getChanges')));
 
     $parser = new DifferentialHunkParser();
 
     return $parser->parseHunksForHighlightMasks(
       $changeset->getHunks(),
       $this->originalLeft->getHunks(),
       $this->originalRight->getHunks());
   }
 
   /**
    * Set a key for identifying this changeset in the render cache. If set, the
    * parser will attempt to use the changeset render cache, which can improve
    * performance for frequently-viewed changesets.
    *
    * By default, there is no render cache key and parsers do not use the cache.
    * This is appropriate for rarely-viewed changesets.
    *
    * NOTE: Currently, this key must be a valid Differential Changeset ID.
    *
    * @param   string  Key for identifying this changeset in the render cache.
    * @return  this
    */
   public function setRenderCacheKey($key) {
     $this->renderCacheKey = $key;
     return $this;
   }
 
   private function getRenderCacheKey() {
     return $this->renderCacheKey;
   }
 
   public function setChangeset(DifferentialChangeset $changeset) {
     $this->changeset = $changeset;
 
     $this->setFilename($changeset->getFilename());
 
     return $this;
   }
 
   public function setWhitespaceMode($whitespace_mode) {
     $this->whitespaceMode = $whitespace_mode;
     return $this;
   }
 
   public function setRenderingReference($ref) {
     $this->renderingReference = $ref;
     return $this;
   }
 
   private function getRenderingReference() {
     return $this->renderingReference;
   }
 
   public function getChangeset() {
     return $this->changeset;
   }
 
   public function setFilename($filename) {
     $this->filename = $filename;
     return $this;
   }
 
   public function setHandles(array $handles) {
     assert_instances_of($handles, 'PhabricatorObjectHandle');
     $this->handles = $handles;
     return $this;
   }
 
   public function setMarkupEngine(PhabricatorMarkupEngine $engine) {
     $this->markupEngine = $engine;
     return $this;
   }
 
   public function setUser(PhabricatorUser $user) {
     $this->user = $user;
     return $this;
   }
 
   public function getUser() {
     return $this->user;
   }
 
   public function setCoverage($coverage) {
     $this->coverage = $coverage;
     return $this;
   }
   private function getCoverage() {
     return $this->coverage;
   }
 
   public function parseInlineComment(
     PhabricatorInlineCommentInterface $comment) {
 
     // Parse only comments which are actually visible.
     if ($this->isCommentVisibleOnRenderedDiff($comment)) {
       $this->comments[] = $comment;
     }
     return $this;
   }
 
   private function loadCache() {
     $render_cache_key = $this->getRenderCacheKey();
     if (!$render_cache_key) {
       return false;
     }
 
     $data = null;
 
     $changeset = new DifferentialChangeset();
     $conn_r = $changeset->establishConnection('r');
     $data = queryfx_one(
       $conn_r,
       'SELECT * FROM %T WHERE id = %d',
       $changeset->getTableName().'_parse_cache',
       $render_cache_key);
 
     if (!$data) {
       return false;
     }
 
     if ($data['cache'][0] == '{') {
       // This is likely an old-style JSON cache which we will not be able to
       // deserialize.
       return false;
     }
 
     $data = unserialize($data['cache']);
     if (!is_array($data) || !$data) {
       return false;
     }
 
     foreach (self::getCacheableProperties() as $cache_key) {
       if (!array_key_exists($cache_key, $data)) {
         // If we're missing a cache key, assume we're looking at an old cache
         // and ignore it.
         return false;
       }
     }
 
     if ($data['cacheVersion'] !== self::CACHE_VERSION) {
       return false;
     }
 
     // Someone displays contents of a partially cached shielded file.
     if (!isset($data['newRender']) && (!$this->isTopLevel || $this->comments)) {
       return false;
     }
 
     unset($data['cacheVersion'], $data['cacheHost']);
     $cache_prop = array_select_keys($data, self::getCacheableProperties());
     foreach ($cache_prop as $cache_key => $v) {
       $this->$cache_key = $v;
     }
 
     return true;
   }
 
   protected static function getCacheableProperties() {
     return array(
       'visible',
       'new',
       'old',
       'intra',
       'newRender',
       'oldRender',
       'specialAttributes',
       'hunkStartLines',
       'cacheVersion',
       'cacheHost',
       'highlightingDisabled',
     );
   }
 
   public function saveCache() {
     if ($this->highlightErrors) {
       return false;
     }
 
     $render_cache_key = $this->getRenderCacheKey();
     if (!$render_cache_key) {
       return false;
     }
 
     $cache = array();
     foreach (self::getCacheableProperties() as $cache_key) {
       switch ($cache_key) {
         case 'cacheVersion':
           $cache[$cache_key] = self::CACHE_VERSION;
           break;
         case 'cacheHost':
           $cache[$cache_key] = php_uname('n');
           break;
         default:
           $cache[$cache_key] = $this->$cache_key;
           break;
       }
     }
     $cache = serialize($cache);
 
     // We don't want to waste too much space by a single changeset.
     if (strlen($cache) > self::CACHE_MAX_SIZE) {
       return;
     }
 
     $changeset = new DifferentialChangeset();
     $conn_w = $changeset->establishConnection('w');
 
     $unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
       try {
         queryfx(
           $conn_w,
           'INSERT INTO %T (id, cache, dateCreated) VALUES (%d, %B, %d)
             ON DUPLICATE KEY UPDATE cache = VALUES(cache)',
           DifferentialChangeset::TABLE_CACHE,
           $render_cache_key,
           $cache,
           time());
       } catch (AphrontQueryException $ex) {
         // Ignore these exceptions. A common cause is that the cache is
         // larger than 'max_allowed_packet', in which case we're better off
         // not writing it.
 
         // TODO: It would be nice to tailor this more narrowly.
       }
     unset($unguarded);
   }
 
   private function markGenerated($new_corpus_block = '') {
     $generated_guess = (strpos($new_corpus_block, '@'.'generated') !== false);
 
     if (!$generated_guess) {
       $generated_path_regexps = PhabricatorEnv::getEnvConfig(
         'differential.generated-paths');
       foreach ($generated_path_regexps as $regexp) {
         if (preg_match($regexp, $this->changeset->getFilename())) {
           $generated_guess = true;
           break;
         }
       }
     }
 
     $event = new PhabricatorEvent(
       PhabricatorEventType::TYPE_DIFFERENTIAL_WILLMARKGENERATED,
       array(
         'corpus' => $new_corpus_block,
         'is_generated' => $generated_guess,
       )
     );
     PhutilEventEngine::dispatchEvent($event);
 
     $generated = $event->getValue('is_generated');
     $this->specialAttributes[self::ATTR_GENERATED] = $generated;
   }
 
   public function isGenerated() {
     return idx($this->specialAttributes, self::ATTR_GENERATED, false);
   }
 
   public function isDeleted() {
     return idx($this->specialAttributes, self::ATTR_DELETED, false);
   }
 
   public function isUnchanged() {
     return idx($this->specialAttributes, self::ATTR_UNCHANGED, false);
   }
 
   public function isWhitespaceOnly() {
     return idx($this->specialAttributes, self::ATTR_WHITELINES, false);
   }
 
   public function isMoveAway() {
     return idx($this->specialAttributes, self::ATTR_MOVEAWAY, false);
   }
 
   private function applyIntraline(&$render, $intra, $corpus) {
 
     foreach ($render as $key => $text) {
       if (isset($intra[$key])) {
         $render[$key] = ArcanistDiffUtils::applyIntralineDiff(
           $text,
           $intra[$key]);
       }
     }
   }
 
   private function getHighlightFuture($corpus) {
     $language = $this->highlightAs;
 
     if (!$language) {
       $language = $this->highlightEngine->getLanguageFromFilename(
         $this->filename);
 
       if (($language != 'txt') &&
           (strlen($corpus) > self::HIGHLIGHT_BYTE_LIMIT)) {
         $this->highlightingDisabled = true;
         $language = 'txt';
       }
     }
 
     return $this->highlightEngine->getHighlightFuture(
       $language,
       $corpus);
   }
 
   protected function processHighlightedSource($data, $result) {
 
     $result_lines = phutil_split_lines($result);
     foreach ($data as $key => $info) {
       if (!$info) {
         unset($result_lines[$key]);
       }
     }
     return $result_lines;
   }
 
   private function tryCacheStuff() {
     $whitespace_mode = $this->whitespaceMode;
     switch ($whitespace_mode) {
       case self::WHITESPACE_SHOW_ALL:
       case self::WHITESPACE_IGNORE_TRAILING:
       case self::WHITESPACE_IGNORE_ALL:
         break;
       default:
         $whitespace_mode = self::WHITESPACE_IGNORE_MOST;
         break;
     }
 
     $skip_cache = ($whitespace_mode != self::WHITESPACE_IGNORE_MOST);
     if ($this->disableCache) {
       $skip_cache = true;
     }
 
     if ($this->characterEncoding) {
       $skip_cache = true;
     }
 
     if ($this->highlightAs) {
       $skip_cache = true;
     }
 
     $this->whitespaceMode = $whitespace_mode;
 
     $changeset = $this->changeset;
 
     if ($changeset->getFileType() != DifferentialChangeType::FILE_TEXT &&
         $changeset->getFileType() != DifferentialChangeType::FILE_SYMLINK) {
 
       $this->markGenerated();
 
     } else {
       if ($skip_cache || !$this->loadCache()) {
         $this->process();
         if (!$skip_cache) {
           $this->saveCache();
         }
       }
     }
   }
 
   private function process() {
     $whitespace_mode = $this->whitespaceMode;
     $changeset = $this->changeset;
 
     $ignore_all = (($whitespace_mode == self::WHITESPACE_IGNORE_MOST) ||
                   ($whitespace_mode == self::WHITESPACE_IGNORE_ALL));
 
     $force_ignore = ($whitespace_mode == self::WHITESPACE_IGNORE_ALL);
 
     if (!$force_ignore) {
       if ($ignore_all && $changeset->getWhitespaceMatters()) {
         $ignore_all = false;
       }
     }
 
     // The "ignore all whitespace" algorithm depends on rediffing the
     // files, and we currently need complete representations of both
     // files to do anything reasonable. If we only have parts of the files,
     // don't use the "ignore all" algorithm.
     if ($ignore_all) {
       $hunks = $changeset->getHunks();
       if (count($hunks) !== 1) {
         $ignore_all = false;
       } else {
         $first_hunk = reset($hunks);
         if ($first_hunk->getOldOffset() != 1 ||
             $first_hunk->getNewOffset() != 1) {
             $ignore_all = false;
         }
       }
     }
 
     if ($ignore_all) {
       $old_file = $changeset->makeOldFile();
       $new_file = $changeset->makeNewFile();
       if ($old_file == $new_file) {
         // If the old and new files are exactly identical, the synthetic
         // diff below will give us nonsense and whitespace modes are
         // irrelevant anyway. This occurs when you, e.g., copy a file onto
         // itself in Subversion (see T271).
         $ignore_all = false;
       }
     }
 
     $hunk_parser = new DifferentialHunkParser();
     $hunk_parser->setWhitespaceMode($whitespace_mode);
     $hunk_parser->parseHunksForLineData($changeset->getHunks());
 
     // Depending on the whitespace mode, we may need to compute a different
     // set of changes than the set of changes in the hunk data (specificaly,
     // we might want to consider changed lines which have only whitespace
     // changes as unchanged).
     if ($ignore_all) {
       $engine = new PhabricatorDifferenceEngine();
       $engine->setIgnoreWhitespace(true);
       $no_whitespace_changeset = $engine->generateChangesetFromFileContent(
         $old_file,
         $new_file);
 
       $type_parser = new DifferentialHunkParser();
       $type_parser->parseHunksForLineData($no_whitespace_changeset->getHunks());
 
       $hunk_parser->setOldLineTypeMap($type_parser->getOldLineTypeMap());
       $hunk_parser->setNewLineTypeMap($type_parser->getNewLineTypeMap());
     }
 
     $hunk_parser->reparseHunksForSpecialAttributes();
 
     $unchanged = false;
     if (!$hunk_parser->getHasAnyChanges()) {
       $filetype = $this->changeset->getFileType();
       if ($filetype == DifferentialChangeType::FILE_TEXT ||
           $filetype == DifferentialChangeType::FILE_SYMLINK) {
         $unchanged = true;
       }
     }
 
     $moveaway = false;
     $changetype = $this->changeset->getChangeType();
     if ($changetype == DifferentialChangeType::TYPE_MOVE_AWAY) {
       $moveaway = true;
     }
 
     $this->setSpecialAttributes(array(
       self::ATTR_UNCHANGED  => $unchanged,
       self::ATTR_DELETED    => $hunk_parser->getIsDeleted(),
       self::ATTR_WHITELINES => !$hunk_parser->getHasTextChanges(),
       self::ATTR_MOVEAWAY   => $moveaway,
     ));
 
     $hunk_parser->generateIntraLineDiffs();
     $hunk_parser->generateVisibileLinesMask();
 
     $this->setOldLines($hunk_parser->getOldLines());
     $this->setNewLines($hunk_parser->getNewLines());
     $this->setIntraLineDiffs($hunk_parser->getIntraLineDiffs());
     $this->setVisibileLinesMask($hunk_parser->getVisibleLinesMask());
     $this->hunkStartLines = $hunk_parser->getHunkStartLines(
       $changeset->getHunks());
 
     $new_corpus = $hunk_parser->getNewCorpus();
     $new_corpus_block = implode('', $new_corpus);
     $this->markGenerated($new_corpus_block);
 
     if ($this->isTopLevel &&
         !$this->comments &&
           ($this->isGenerated() ||
            $this->isUnchanged() ||
            $this->isDeleted())) {
       return;
     }
 
     $old_corpus = $hunk_parser->getOldCorpus();
     $old_corpus_block = implode('', $old_corpus);
     $old_future = $this->getHighlightFuture($old_corpus_block);
     $new_future = $this->getHighlightFuture($new_corpus_block);
     $futures = array(
       'old' => $old_future,
       'new' => $new_future,
     );
     $corpus_blocks = array(
       'old' => $old_corpus_block,
       'new' => $new_corpus_block,
     );
 
     $this->highlightErrors = false;
     foreach (new FutureIterator($futures) as $key => $future) {
       try {
         try {
           $highlighted = $future->resolve();
         } catch (PhutilSyntaxHighlighterException $ex) {
           $this->highlightErrors = true;
           $highlighted = id(new PhutilDefaultSyntaxHighlighter())
             ->getHighlightFuture($corpus_blocks[$key])
             ->resolve();
         }
         switch ($key) {
         case 'old':
           $this->oldRender = $this->processHighlightedSource(
             $this->old,
             $highlighted);
           break;
         case 'new':
           $this->newRender = $this->processHighlightedSource(
             $this->new,
             $highlighted);
           break;
         }
       } catch (Exception $ex) {
         phlog($ex);
         throw $ex;
       }
     }
 
     $this->applyIntraline(
       $this->oldRender,
       ipull($this->intra, 0),
       $old_corpus);
     $this->applyIntraline(
       $this->newRender,
       ipull($this->intra, 1),
       $new_corpus);
   }
 
   private function shouldRenderPropertyChangeHeader($changeset) {
     if (!$this->isTopLevel) {
       // We render properties only at top level; otherwise we get multiple
       // copies of them when a user clicks "Show More".
       return false;
     }
 
     return true;
   }
 
   public function render(
     $range_start  = null,
     $range_len    = null,
     $mask_force   = array()) {
 
     // "Top level" renders are initial requests for the whole file, versus
     // requests for a specific range generated by clicking "show more". We
     // generate property changes and "shield" UI elements only for toplevel
     // requests.
     $this->isTopLevel = (($range_start === null) && ($range_len === null));
     $this->highlightEngine = PhabricatorSyntaxHighlighter::newEngine();
 
     $encoding = null;
     if ($this->characterEncoding) {
       // We are forcing this changeset to be interpreted with a specific
       // character encoding, so force all the hunks into that encoding and
       // propagate it to the renderer.
       $encoding = $this->characterEncoding;
       foreach ($this->changeset->getHunks() as $hunk) {
         $hunk->forceEncoding($this->characterEncoding);
       }
     } else {
       // We're just using the default, so tell the renderer what that is
       // (by reading the encoding from the first hunk).
       foreach ($this->changeset->getHunks() as $hunk) {
         $encoding = $hunk->getDataEncoding();
         break;
       }
     }
 
     $this->tryCacheStuff();
 
     // If we're rendering in an offset mode, treat the range numbers as line
     // numbers instead of rendering offsets.
     $offset_mode = $this->getOffsetMode();
     if ($offset_mode) {
       if ($offset_mode == 'new') {
         $offset_map = $this->new;
       } else {
         $offset_map = $this->old;
       }
 
       $range_end = $this->getOffset($offset_map, $range_start + $range_len);
       $range_start = $this->getOffset($offset_map, $range_start);
-      $range_len = $range_end - $range_start;
+      $range_len = ($range_end - $range_start);
     }
 
     $render_pch = $this->shouldRenderPropertyChangeHeader($this->changeset);
 
     $rows = max(
       count($this->old),
       count($this->new));
 
     $renderer = $this->getRenderer()
       ->setUser($this->getUser())
       ->setChangeset($this->changeset)
       ->setRenderPropertyChangeHeader($render_pch)
       ->setIsTopLevel($this->isTopLevel)
       ->setOldRender($this->oldRender)
       ->setNewRender($this->newRender)
       ->setHunkStartLines($this->hunkStartLines)
       ->setOldChangesetID($this->leftSideChangesetID)
       ->setNewChangesetID($this->rightSideChangesetID)
       ->setOldAttachesToNewFile($this->leftSideAttachesToNewFile)
       ->setNewAttachesToNewFile($this->rightSideAttachesToNewFile)
       ->setCodeCoverage($this->getCoverage())
       ->setRenderingReference($this->getRenderingReference())
       ->setMarkupEngine($this->markupEngine)
       ->setHandles($this->handles)
       ->setOldLines($this->old)
       ->setNewLines($this->new)
       ->setOriginalCharacterEncoding($encoding)
       ->setShowEditAndReplyLinks($this->getShowEditAndReplyLinks())
       ->setCanMarkDone($this->getCanMarkDone())
       ->setObjectOwnerPHID($this->getObjectOwnerPHID())
       ->setHighlightingDisabled($this->highlightingDisabled);
 
     $shield = null;
     if ($this->isTopLevel && !$this->comments) {
       if ($this->isGenerated()) {
         $shield = $renderer->renderShield(
           pht(
             'This file contains generated code, which does not normally '.
             'need to be reviewed.'));
       } else if ($this->isMoveAway()) {
         // We put an empty shield on these files. Normally, they do not have
         // any diff content anyway. However, if they come through `arc`, they
         // may have content. We don't want to show it (it's not useful) and
         // we bailed out of fully processing it earlier anyway.
 
         // We could show a message like "this file was moved", but we show
         // that as a change header anyway, so it would be redundant. Instead,
         // just render an empty shield to skip rendering the diff body.
         $shield = '';
       } else if ($this->isUnchanged()) {
         $type = 'text';
         if (!$rows) {
           // NOTE: Normally, diffs which don't change files do not include
           // file content (for example, if you "chmod +x" a file and then
           // run "git show", the file content is not available). Similarly,
           // if you move a file from A to B without changing it, diffs normally
           // do not show the file content. In some cases `arc` is able to
           // synthetically generate content for these diffs, but for raw diffs
           // we'll never have it so we need to be prepared to not render a link.
           $type = 'none';
         }
 
         $type_add = DifferentialChangeType::TYPE_ADD;
         if ($this->changeset->getChangeType() == $type_add) {
           // Although the generic message is sort of accurate in a technical
           // sense, this more-tailored message is less confusing.
           $shield = $renderer->renderShield(
             pht('This is an empty file.'),
             $type);
         } else {
           $shield = $renderer->renderShield(
             pht('The contents of this file were not changed.'),
             $type);
         }
       } else if ($this->isWhitespaceOnly()) {
         $shield = $renderer->renderShield(
           pht('This file was changed only by adding or removing whitespace.'),
           'whitespace');
       } else if ($this->isDeleted()) {
         $shield = $renderer->renderShield(
           pht('This file was completely deleted.'));
       } else if ($this->changeset->getAffectedLineCount() > 2500) {
         $shield = $renderer->renderShield(
           pht(
             'This file has a very large number of changes (%s lines).',
             new PhutilNumber($this->changeset->getAffectedLineCount())));
       }
     }
 
     if ($shield !== null) {
       return $renderer->renderChangesetTable($shield);
     }
 
     // This request should render the "undershield" headers if it's a top-level
     // request which made it this far (indicating the changeset has no shield)
     // or it's a request with no mask information (indicating it's the request
     // that removes the rendering shield). Possibly, this second class of
     // request might need to be made more explicit.
     $is_undershield = (empty($mask_force) || $this->isTopLevel);
     $renderer->setIsUndershield($is_undershield);
 
     $old_comments = array();
     $new_comments = array();
     $old_mask = array();
     $new_mask = array();
     $feedback_mask = array();
 
     if ($this->comments) {
       // If there are any comments which appear in sections of the file which
       // we don't have, we're going to move them backwards to the closest
       // earlier line. Two cases where this may happen are:
       //
       //   - Porting ghost comments forward into a file which was mostly
       //     deleted.
       //   - Porting ghost comments forward from a full-context diff to a
       //     partial-context diff.
 
       list($old_backmap, $new_backmap) = $this->buildLineBackmaps();
 
       foreach ($this->comments as $comment) {
         $new_side = $this->isCommentOnRightSideWhenDisplayed($comment);
 
         $line = $comment->getLineNumber();
         if ($new_side) {
           $back_line = $new_backmap[$line];
         } else {
           $back_line = $old_backmap[$line];
         }
 
         if ($back_line != $line) {
           // TODO: This should probably be cleaner, but just be simple and
           // obvious for now.
           $ghost = $comment->getIsGhost();
           if ($ghost) {
             $moved = pht(
               'This comment originally appeared on line %s, but that line '.
               'does not exist in this version of the diff. It has been '.
               'moved backward to the nearest line.',
               new PhutilNumber($line));
             $ghost['reason'] = $ghost['reason']."\n\n".$moved;
             $comment->setIsGhost($ghost);
           }
 
           $comment->setLineNumber($back_line);
           $comment->setLineLength(0);
 
         }
 
         $start = max($comment->getLineNumber() - self::LINES_CONTEXT, 0);
         $end = $comment->getLineNumber() +
           $comment->getLineLength() +
           self::LINES_CONTEXT;
         for ($ii = $start; $ii <= $end; $ii++) {
           if ($new_side) {
             $new_mask[$ii] = true;
           } else {
             $old_mask[$ii] = true;
           }
         }
       }
 
       foreach ($this->old as $ii => $old) {
         if (isset($old['line']) && isset($old_mask[$old['line']])) {
           $feedback_mask[$ii] = true;
         }
       }
 
       foreach ($this->new as $ii => $new) {
         if (isset($new['line']) && isset($new_mask[$new['line']])) {
           $feedback_mask[$ii] = true;
         }
       }
 
       $this->comments = $this->reorderAndThreadComments($this->comments);
 
       foreach ($this->comments as $comment) {
         $final = $comment->getLineNumber() +
           $comment->getLineLength();
         $final = max(1, $final);
         if ($this->isCommentOnRightSideWhenDisplayed($comment)) {
           $new_comments[$final][] = $comment;
         } else {
           $old_comments[$final][] = $comment;
         }
       }
     }
     $renderer
       ->setOldComments($old_comments)
       ->setNewComments($new_comments);
 
     switch ($this->changeset->getFileType()) {
       case DifferentialChangeType::FILE_IMAGE:
         $old = null;
         $new = null;
         // TODO: Improve the architectural issue as discussed in D955
         // https://secure.phabricator.com/D955
         $reference = $this->getRenderingReference();
         $parts = explode('/', $reference);
         if (count($parts) == 2) {
           list($id, $vs) = $parts;
         } else {
           $id = $parts[0];
           $vs = 0;
         }
         $id = (int)$id;
         $vs = (int)$vs;
 
         if (!$vs) {
           $metadata = $this->changeset->getMetadata();
           $data = idx($metadata, 'attachment-data');
 
           $old_phid = idx($metadata, 'old:binary-phid');
           $new_phid = idx($metadata, 'new:binary-phid');
         } else {
           $vs_changeset = id(new DifferentialChangeset())->load($vs);
           $old_phid = null;
           $new_phid = null;
 
           // TODO: This is spooky, see D6851
           if ($vs_changeset) {
             $vs_metadata = $vs_changeset->getMetadata();
             $old_phid = idx($vs_metadata, 'new:binary-phid');
           }
 
           $changeset = id(new DifferentialChangeset())->load($id);
           if ($changeset) {
             $metadata = $changeset->getMetadata();
             $new_phid = idx($metadata, 'new:binary-phid');
           }
         }
 
         if ($old_phid || $new_phid) {
           // grab the files, (micro) optimization for 1 query not 2
           $file_phids = array();
           if ($old_phid) {
             $file_phids[] = $old_phid;
           }
           if ($new_phid) {
             $file_phids[] = $new_phid;
           }
 
           $files = id(new PhabricatorFileQuery())
             ->setViewer($this->getUser())
             ->withPHIDs($file_phids)
             ->execute();
           foreach ($files as $file) {
             if (empty($file)) {
               continue;
             }
             if ($file->getPHID() == $old_phid) {
               $old = $file;
             } else if ($file->getPHID() == $new_phid) {
               $new = $file;
             }
           }
         }
 
         $renderer->attachOldFile($old);
         $renderer->attachNewFile($new);
 
         return $renderer->renderFileChange($old, $new, $id, $vs);
       case DifferentialChangeType::FILE_DIRECTORY:
       case DifferentialChangeType::FILE_BINARY:
         $output = $renderer->renderChangesetTable(null);
         return $output;
     }
 
     if ($this->originalLeft && $this->originalRight) {
       list($highlight_old, $highlight_new) = $this->diffOriginals();
       $highlight_old = array_flip($highlight_old);
       $highlight_new = array_flip($highlight_new);
       $renderer
         ->setHighlightOld($highlight_old)
         ->setHighlightNew($highlight_new);
     }
     $renderer
       ->setOriginalOld($this->originalLeft)
       ->setOriginalNew($this->originalRight);
 
     if ($range_start === null) {
       $range_start = 0;
     }
     if ($range_len === null) {
       $range_len = $rows;
     }
     $range_len = min($range_len, $rows - $range_start);
 
     list($gaps, $mask, $depths) = $this->calculateGapsMaskAndDepths(
       $mask_force,
       $feedback_mask,
       $range_start,
       $range_len);
 
     $renderer
       ->setGaps($gaps)
       ->setMask($mask)
       ->setDepths($depths);
 
     $html = $renderer->renderTextChange(
       $range_start,
       $range_len,
       $rows);
 
     return $renderer->renderChangesetTable($html);
   }
 
   /**
    * This function calculates a lot of stuff we need to know to display
    * the diff:
    *
    * Gaps - compute gaps in the visible display diff, where we will render
    * "Show more context" spacers. If a gap is smaller than the context size,
    * we just display it. Otherwise, we record it into $gaps and will render a
    * "show more context" element instead of diff text below. A given $gap
    * is a tuple of $gap_line_number_start and $gap_length.
    *
    * Mask - compute the actual lines that need to be shown (because they
    * are near changes lines, near inline comments, or the request has
    * explicitly asked for them, i.e. resulting from the user clicking
    * "show more"). The $mask returned is a sparesely populated dictionary
    * of $visible_line_number => true.
    *
    * Depths - compute how indented any given line is. The $depths returned
    * is a sparesely populated dictionary of $visible_line_number => $depth.
    *
    * This function also has the side effect of modifying member variable
    * new such that tabs are normalized to spaces for each line of the diff.
    *
    * @return array($gaps, $mask, $depths)
    */
   private function calculateGapsMaskAndDepths(
     $mask_force,
     $feedback_mask,
     $range_start,
     $range_len) {
 
     // Calculate gaps and mask first
     $gaps = array();
     $gap_start = 0;
     $in_gap = false;
     $base_mask = $this->visible + $mask_force + $feedback_mask;
     $base_mask[$range_start + $range_len] = true;
     for ($ii = $range_start; $ii <= $range_start + $range_len; $ii++) {
       if (isset($base_mask[$ii])) {
         if ($in_gap) {
           $gap_length = $ii - $gap_start;
           if ($gap_length <= self::LINES_CONTEXT) {
             for ($jj = $gap_start; $jj <= $gap_start + $gap_length; $jj++) {
               $base_mask[$jj] = true;
             }
           } else {
             $gaps[] = array($gap_start, $gap_length);
           }
           $in_gap = false;
         }
       } else {
         if (!$in_gap) {
           $gap_start = $ii;
           $in_gap = true;
         }
       }
     }
     $gaps = array_reverse($gaps);
     $mask = $base_mask;
 
     // Time to calculate depth.
     // We need to go backwards to properly indent whitespace in this code:
     //
     //   0: class C {
     //   1:
     //   1:   function f() {
     //   2:
     //   2:     return;
     //   1:
     //   1:   }
     //   0:
     //   0: }
     //
     $depths = array();
     $last_depth = 0;
     $range_end = $range_start + $range_len;
     if (!isset($this->new[$range_end])) {
       $range_end--;
     }
     for ($ii = $range_end; $ii >= $range_start; $ii--) {
       // We need to expand tabs to process mixed indenting and to round
       // correctly later.
       $line = str_replace("\t", '  ', $this->new[$ii]['text']);
       $trimmed = ltrim($line);
       if ($trimmed != '') {
         // We round down to flatten "/**" and " *".
         $last_depth = floor((strlen($line) - strlen($trimmed)) / 2);
       }
       $depths[$ii] = $last_depth;
     }
 
     return array($gaps, $mask, $depths);
   }
 
   /**
    * Determine if an inline comment will appear on the rendered diff,
    * taking into consideration which halves of which changesets will actually
    * be shown.
    *
    * @param PhabricatorInlineCommentInterface Comment to test for visibility.
    * @return bool True if the comment is visible on the rendered diff.
    */
   private function isCommentVisibleOnRenderedDiff(
     PhabricatorInlineCommentInterface $comment) {
 
     $changeset_id = $comment->getChangesetID();
     $is_new = $comment->getIsNewFile();
 
     if ($changeset_id == $this->rightSideChangesetID &&
         $is_new == $this->rightSideAttachesToNewFile) {
         return true;
     }
 
     if ($changeset_id == $this->leftSideChangesetID &&
         $is_new == $this->leftSideAttachesToNewFile) {
         return true;
     }
 
     return false;
   }
 
 
   /**
    * Determine if a comment will appear on the right side of the display diff.
    * Note that the comment must appear somewhere on the rendered changeset, as
    * per isCommentVisibleOnRenderedDiff().
    *
    * @param PhabricatorInlineCommentInterface Comment to test for display
    *              location.
    * @return bool True for right, false for left.
    */
   private function isCommentOnRightSideWhenDisplayed(
     PhabricatorInlineCommentInterface $comment) {
 
     if (!$this->isCommentVisibleOnRenderedDiff($comment)) {
       throw new Exception(pht('Comment is not visible on changeset!'));
     }
 
     $changeset_id = $comment->getChangesetID();
     $is_new = $comment->getIsNewFile();
 
     if ($changeset_id == $this->rightSideChangesetID &&
         $is_new == $this->rightSideAttachesToNewFile) {
       return true;
     }
 
     return false;
   }
 
   /**
    * Parse the 'range' specification that this class and the client-side JS
    * emit to indicate that a user clicked "Show more..." on a diff. Generally,
    * use is something like this:
    *
    *   $spec = $request->getStr('range');
    *   $parsed = DifferentialChangesetParser::parseRangeSpecification($spec);
    *   list($start, $end, $mask) = $parsed;
    *   $parser->render($start, $end, $mask);
    *
    * @param string Range specification, indicating the range of the diff that
    *               should be rendered.
    * @return tuple List of <start, end, mask> suitable for passing to
    *               @{method:render}.
    */
   public static function parseRangeSpecification($spec) {
     $range_s = null;
     $range_e = null;
     $mask = array();
 
     if ($spec) {
       $match = null;
       if (preg_match('@^(\d+)-(\d+)(?:/(\d+)-(\d+))?$@', $spec, $match)) {
         $range_s = (int)$match[1];
         $range_e = (int)$match[2];
         if (count($match) > 3) {
           $start = (int)$match[3];
           $len = (int)$match[4];
           for ($ii = $start; $ii < $start + $len; $ii++) {
             $mask[$ii] = true;
           }
         }
       }
     }
 
     return array($range_s, $range_e, $mask);
   }
 
   /**
    * Render "modified coverage" information; test coverage on modified lines.
    * This synthesizes diff information with unit test information into a useful
    * indicator of how well tested a change is.
    */
   public function renderModifiedCoverage() {
     $na = phutil_tag('em', array(), '-');
 
     $coverage = $this->getCoverage();
     if (!$coverage) {
       return $na;
     }
 
     $covered = 0;
     $not_covered = 0;
 
     foreach ($this->new as $k => $new) {
       if (!$new['line']) {
         continue;
       }
 
       if (!$new['type']) {
         continue;
       }
 
       if (empty($coverage[$new['line'] - 1])) {
         continue;
       }
 
       switch ($coverage[$new['line'] - 1]) {
         case 'C':
           $covered++;
           break;
         case 'U':
           $not_covered++;
           break;
       }
     }
 
     if (!$covered && !$not_covered) {
       return $na;
     }
 
     return sprintf('%d%%', 100 * ($covered / ($covered + $not_covered)));
   }
 
   public function detectCopiedCode(
     array $changesets,
     $min_width = 30,
     $min_lines = 3) {
 
     assert_instances_of($changesets, 'DifferentialChangeset');
 
     $map = array();
     $files = array();
     $types = array();
     foreach ($changesets as $changeset) {
       $file = $changeset->getFilename();
       foreach ($changeset->getHunks() as $hunk) {
         $lines = $hunk->getStructuredOldFile();
         foreach ($lines as $line => $info) {
           $type = $info['type'];
           if ($type == '\\') {
             continue;
           }
           $types[$file][$line] = $type;
 
           $text = $info['text'];
           $text = trim($text);
           $files[$file][$line] = $text;
 
           if (strlen($text) >= $min_width) {
             $map[$text][] = array($file, $line);
           }
         }
       }
     }
 
     foreach ($changesets as $changeset) {
       $copies = array();
       foreach ($changeset->getHunks() as $hunk) {
         $added = $hunk->getStructuredNewFile();
         $atype = array();
 
         foreach ($added as $line => $info) {
           $atype[$line] = $info['type'];
           $added[$line] = trim($info['text']);
         }
 
         $skip_lines = 0;
         foreach ($added as $line => $code) {
           if ($skip_lines) {
             // We're skipping lines that we already processed because we
             // extended a block above them downward to include them.
             $skip_lines--;
             continue;
           }
 
           if ($atype[$line] !== '+') {
             // This line hasn't been changed in the new file, so don't try
             // to figure out where it came from.
             continue;
           }
 
           if (empty($map[$code])) {
             // This line was too short to trigger copy/move detection.
             continue;
           }
 
           if (count($map[$code]) > 16) {
             // If there are a large number of identical lines in this diff,
             // don't try to figure out where this block came from: the analysis
             // is O(N^2), since we need to compare every line against every
             // other line. Even if we arrive at a result, it is unlikely to be
             // meaningful. See T5041.
             continue;
           }
 
           $best_length = 0;
 
           // Explore all candidates.
           foreach ($map[$code] as $val) {
             list($file, $orig_line) = $val;
             $length = 1;
 
             // Search backward and forward to find all of the adjacent lines
             // which match.
             foreach (array(-1, 1) as $direction) {
               $offset = $direction;
               while (true) {
                 if (isset($copies[$line + $offset])) {
                   // If we run into a block above us which we've already
                   // attributed to a move or copy from elsewhere, stop
                   // looking.
                   break;
                 }
 
                 if (!isset($added[$line + $offset])) {
                   // If we've run off the beginning or end of the new file,
                   // stop looking.
                   break;
                 }
 
                 if (!isset($files[$file][$orig_line + $offset])) {
                   // If we've run off the beginning or end of the original
                   // file, we also stop looking.
                   break;
                 }
 
                 $old = $files[$file][$orig_line + $offset];
                 $new = $added[$line + $offset];
                 if ($old !== $new) {
                   // If the old line doesn't match the new line, stop
                   // looking.
                   break;
                 }
 
                 $length++;
                 $offset += $direction;
               }
             }
 
             if ($length < $best_length) {
               // If we already know of a better source (more matching lines)
               // for this move/copy, stick with that one. We prefer long
               // copies/moves which match a lot of context over short ones.
               continue;
             }
 
             if ($length == $best_length) {
               if (idx($types[$file], $orig_line) != '-') {
                 // If we already know of an equally good source (same number
                 // of matching lines) and this isn't a move, stick with the
                 // other one. We prefer moves over copies.
                 continue;
               }
             }
 
             $best_length = $length;
             // ($offset - 1) contains number of forward matching lines.
             $best_offset = $offset - 1;
             $best_file = $file;
             $best_line = $orig_line;
           }
 
           $file = ($best_file == $changeset->getFilename() ? '' : $best_file);
           for ($i = $best_length; $i--; ) {
             $type = idx($types[$best_file], $best_line + $best_offset - $i);
             $copies[$line + $best_offset - $i] = ($best_length < $min_lines
               ? array() // Ignore short blocks.
               : array($file, $best_line + $best_offset - $i, $type));
           }
 
           $skip_lines = $best_offset;
         }
       }
 
       $copies = array_filter($copies);
       if ($copies) {
         $metadata = $changeset->getMetadata();
         $metadata['copy:lines'] = $copies;
         $changeset->setMetadata($metadata);
       }
     }
     return $changesets;
   }
 
   /**
    * Build maps from lines comments appear on to actual lines.
    */
   private function buildLineBackmaps() {
     $old_back = array();
     $new_back = array();
     foreach ($this->old as $ii => $old) {
       $old_back[$old['line']] = $old['line'];
     }
     foreach ($this->new as $ii => $new) {
       $new_back[$new['line']] = $new['line'];
     }
 
     $max_old_line = 0;
     $max_new_line = 0;
     foreach ($this->comments as $comment) {
       if ($this->isCommentOnRightSideWhenDisplayed($comment)) {
         $max_new_line = max($max_new_line, $comment->getLineNumber());
       } else {
         $max_old_line = max($max_old_line, $comment->getLineNumber());
       }
     }
 
     $cursor = 1;
     for ($ii = 1; $ii <= $max_old_line; $ii++) {
       if (empty($old_back[$ii])) {
         $old_back[$ii] = $cursor;
       } else {
         $cursor = $old_back[$ii];
       }
     }
 
     $cursor = 1;
     for ($ii = 1; $ii <= $max_new_line; $ii++) {
       if (empty($new_back[$ii])) {
         $new_back[$ii] = $cursor;
       } else {
         $cursor = $new_back[$ii];
       }
     }
 
     return array($old_back, $new_back);
   }
 
   private function reorderAndThreadComments(array $comments) {
     $comments = msort($comments, 'getID');
 
     // Build an empty map of all the comments we actually have. If a comment
     // is a reply but the parent has gone missing, we don't want it to vanish
     // completely.
     $comment_phids = mpull($comments, 'getPHID');
     $replies = array_fill_keys($comment_phids, array());
 
     // Now, remove all comments which are replies, leaving only the top-level
     // comments.
     foreach ($comments as $key => $comment) {
       $reply_phid = $comment->getReplyToCommentPHID();
       if (isset($replies[$reply_phid])) {
         $replies[$reply_phid][] = $comment;
         unset($comments[$key]);
       }
     }
 
     // For each top level comment, add the comment, then add any replies
     // to it. Do this recursively so threads are shown in threaded order.
     $results = array();
     foreach ($comments as $comment) {
       $results[] = $comment;
       $phid = $comment->getPHID();
       $descendants = $this->getInlineReplies($replies, $phid, 1);
       foreach ($descendants as $descendant) {
         $results[] = $descendant;
       }
     }
 
     // If we have anything left, they were cyclic references. Just dump
     // them in a the end. This should be impossible, but users are very
     // creative.
     foreach ($replies as $phid => $comments) {
       foreach ($comments as $comment) {
         $results[] = $comment;
       }
     }
 
     return $results;
   }
 
   private function getInlineReplies(array &$replies, $phid, $depth) {
     $comments = idx($replies, $phid, array());
     unset($replies[$phid]);
 
     $results = array();
     foreach ($comments as $comment) {
       $results[] = $comment;
       $descendants = $this->getInlineReplies(
         $replies,
         $comment->getPHID(),
         $depth + 1);
       foreach ($descendants as $descendant) {
         $results[] = $descendant;
       }
     }
 
     return $results;
   }
 
   private function getOffset(array $map, $line) {
     if (!$map) {
       return null;
     }
 
     $line = (int)$line;
     foreach ($map as $key => $spec) {
       if ($spec && isset($spec['line'])) {
         if ((int)$spec['line'] >= $line) {
           return $key;
         }
       }
     }
 
     return $key;
   }
 
 }
diff --git a/src/applications/differential/render/DifferentialChangesetOneUpMailRenderer.php b/src/applications/differential/render/DifferentialChangesetOneUpMailRenderer.php
index ee1508d535..cb1fda70c6 100644
--- a/src/applications/differential/render/DifferentialChangesetOneUpMailRenderer.php
+++ b/src/applications/differential/render/DifferentialChangesetOneUpMailRenderer.php
@@ -1,98 +1,100 @@
 <?php
 
 final class DifferentialChangesetOneUpMailRenderer
   extends DifferentialChangesetRenderer {
 
   public function isOneUpRenderer() {
     return true;
   }
 
   protected function getRendererTableClass() {
     return 'diff-1up-mail';
   }
 
   public function getRendererKey() {
     return '1up-mail';
   }
 
   protected function renderChangeTypeHeader($force) {
     return null;
   }
 
   protected function renderUndershieldHeader() {
     return null;
   }
 
   public function renderShield($message, $force = 'default') {
     return null;
   }
 
   protected function renderPropertyChangeHeader() {
     return null;
   }
 
   public function renderFileChange(
     $old_file = null,
     $new_file = null,
     $id = 0,
     $vs = 0) {
     return null;
   }
 
   public function renderTextChange(
     $range_start,
     $range_len,
     $rows) {
 
     $primitives = $this->buildPrimitives($range_start, $range_len);
     return $this->renderPrimitives($primitives, $rows);
   }
 
   protected function renderPrimitives(array $primitives, $rows) {
     $out = array();
     foreach ($primitives as $k => $p) {
       $type = $p['type'];
       switch ($type) {
         case 'old':
         case 'new':
         case 'old-file':
         case 'new-file':
           $is_old = ($type == 'old' || $type == 'old-file');
 
           if ($is_old) {
             if ($p['htype']) {
               $style = 'background: #ffd0d0;';
             } else {
               $style = null;
             }
           } else {
             if ($p['htype']) {
               $style = 'background: #d0ffd0;';
             } else {
               $style =  null;
             }
           }
 
+          $style = "padding: 0 2px; {$style}";
+
           $out[] = phutil_tag(
             'div',
             array(
               'style' => $style,
             ),
             $p['render']);
           break;
         default:
           break;
       }
     }
 
     $style_map = id(new PhabricatorDefaultSyntaxStyle())
       ->getRemarkupStyleMap();
 
     $styled_body = id(new PhutilPygmentizeParser())
       ->setMap($style_map)
       ->parse((string)hsprintf('%s', $out));
 
     return phutil_safe_html($styled_body);
   }
 
 }