diff --git a/src/applications/diffusion/query/history/DiffusionMercurialHistoryQuery.php b/src/applications/diffusion/query/history/DiffusionMercurialHistoryQuery.php
index 5377e820f9..244c54f0a1 100644
--- a/src/applications/diffusion/query/history/DiffusionMercurialHistoryQuery.php
+++ b/src/applications/diffusion/query/history/DiffusionMercurialHistoryQuery.php
@@ -1,89 +1,99 @@
 <?php
 
 final class DiffusionMercurialHistoryQuery extends DiffusionHistoryQuery {
 
   protected function executeQuery() {
     $drequest = $this->getRequest();
 
     $repository = $drequest->getRepository();
     $path = $drequest->getPath();
     $commit_hash = $drequest->getStableCommitName();
 
     $path = DiffusionPathIDQuery::normalizePath($path);
     $path = ltrim($path, '/');
 
     // NOTE: Older versions of Mercurial give different results for these
     // commands (see T1268):
     //
     //   $ hg log -- ''
     //   $ hg log
     //
     // All versions of Mercurial give different results for these commands
     // (merge commits are excluded with the "." version):
     //
     //   $ hg log -- .
     //   $ hg log
     //
     // If we don't have a path component in the query, omit it from the command
     // entirely to avoid these inconsistencies.
 
-    $path_arg = '';
+    // NOTE: When viewing the history of a file, we don't use "-b", because
+    // Mercurial stops history at the branchpoint but we're interested in all
+    // ancestors. When viewing history of a branch, we do use "-b", and thus
+    // stop history (this is more consistent with the Mercurial worldview of
+    // branches).
+
     if (strlen($path)) {
       $path_arg = csprintf('-- %s', $path);
+      $branch_arg = '';
+    } else {
+      $path_arg = '';
+      // NOTE: --branch used to be called --only-branch; use -b for
+      // compatibility.
+      $branch_arg = csprintf('-b %s', $drequest->getBranch());
     }
 
-    // NOTE: --branch used to be called --only-branch; use -b for compatibility.
     list($stdout) = $repository->execxLocalCommand(
-      'log --debug --template %s --limit %d -b %s --rev %s:0 %C',
+      'log --debug --template %s --limit %d %C --rev %s::0 %C',
       '{node};{parents}\\n',
       ($this->getOffset() + $this->getLimit()), // No '--skip' in Mercurial.
-      $drequest->getBranch(),
+      $branch_arg,
       $commit_hash,
       $path_arg);
 
     $lines = explode("\n", trim($stdout));
     $lines = array_slice($lines, $this->getOffset());
 
     $hash_list = array();
     $parent_map = array();
 
     $last = null;
     foreach (array_reverse($lines) as $line) {
       list($hash, $parents) = explode(';', $line);
       $parents = trim($parents);
       if (!$parents) {
         if ($last === null) {
           $parent_map[$hash] = array('...');
         } else {
           $parent_map[$hash] = array($last);
         }
       } else {
         $parents = preg_split('/\s+/', $parents);
         foreach ($parents as $parent) {
           list($plocal, $phash) = explode(':', $parent);
           if (!preg_match('/^0+$/', $phash)) {
             $parent_map[$hash][] = $phash;
           }
         }
         // This may happen for the zeroth commit in repository, both hashes
         // are "000000000...".
         if (empty($parent_map[$hash])) {
           $parent_map[$hash] = array('...');
         }
       }
 
       // The rendering code expects the first commit to be "mainline", like
       // Git. Flip the order so it does the right thing.
       $parent_map[$hash] = array_reverse($parent_map[$hash]);
 
       $hash_list[] = $hash;
       $last = $hash;
     }
 
     $hash_list = array_reverse($hash_list);
     $this->parents = $parent_map;
 
     return $this->loadHistoryForCommitIdentifiers($hash_list);
   }
 
 }
diff --git a/src/applications/diffusion/query/lastmodified/DiffusionMercurialLastModifiedQuery.php b/src/applications/diffusion/query/lastmodified/DiffusionMercurialLastModifiedQuery.php
index 5a5f686351..9a8e648e66 100644
--- a/src/applications/diffusion/query/lastmodified/DiffusionMercurialLastModifiedQuery.php
+++ b/src/applications/diffusion/query/lastmodified/DiffusionMercurialLastModifiedQuery.php
@@ -1,32 +1,32 @@
 <?php
 
 final class DiffusionMercurialLastModifiedQuery
   extends DiffusionLastModifiedQuery {
 
   protected function executeQuery() {
     $drequest = $this->getRequest();
     $repository = $drequest->getRepository();
 
     $path = $drequest->getPath();
 
     list($hash) = $repository->execxLocalCommand(
-      'log --template %s --limit 1 --rev %s:0 -- %s',
+      'log --template %s --limit 1 --rev %s::0 -- %s',
       '{node}',
       $drequest->getCommit(),
       nonempty(ltrim($path, '/'), '.'));
 
     $commit = id(new PhabricatorRepositoryCommit())->loadOneWhere(
       'repositoryID = %d AND commitIdentifier = %s',
       $repository->getID(),
       $hash);
 
     if ($commit) {
       $commit_data = $commit->loadCommitData();
     } else {
       $commit_data = null;
     }
 
     return array($commit, $commit_data);
   }
 
 }