diff --git a/src/applications/diffusion/engine/DiffusionCommitHookEngine.php b/src/applications/diffusion/engine/DiffusionCommitHookEngine.php
--- a/src/applications/diffusion/engine/DiffusionCommitHookEngine.php
+++ b/src/applications/diffusion/engine/DiffusionCommitHookEngine.php
@@ -127,6 +127,35 @@
     $caught = null;
     try {
 
+      if ($this->isPushForReview($all_updates)) {
+        $diff = $this->generateDiffForReview($all_updates);
+
+        // TODO: Enrich this diff on many dimensions; these are required
+        // to save the object.
+        $diff->setLintStatus(DifferentialLintStatus::LINT_NONE);
+        $diff->setUnitStatus(DifferentialUnitStatus::UNIT_NONE);
+
+        $diff->save();
+
+        $diff_uri = PhabricatorEnv::getProductionURI(
+          '/differential/diff/'.$diff->getID().'/');
+
+        $console = PhutilConsole::getConsole();
+        $console->writeErr(
+          "\n%s\n\n",
+          pht(
+            "Success! Created a new diff fom your changes:\n\n    %s\n\n".
+            "Since this was a push for review, your changes will not be\n".
+            "applied to the remote. This push will now be rejected.",
+            $diff_uri));
+
+        // TODO: It would be nice to make Git think this push worked, but
+        // this is just an ease-of-use issue. For now, return an error to
+        // reject the changes.
+
+        return 77;
+      }
+
       try {
         $this->rejectDangerousChanges($ref_updates);
       } catch (DiffusionCommitHookRejectException $ex) {
@@ -252,6 +281,36 @@
     }
   }
 
+  private function isPushForReview(array $ref_updates) {
+    assert_instances_of($ref_updates, 'PhabricatorRepositoryPushLog');
+
+    $type = $this->getRepository()->getVersionControlSystem();
+    switch ($type) {
+      case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
+        return $this->isGitPushForReview($ref_updates);
+      case PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL:
+        return false;
+      case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
+        return false;
+      default:
+        throw new Exception(pht('Unsupported repository type "%s"!', $type));
+    }
+  }
+
+  private function generateDiffForReview(array $ref_updates) {
+    assert_instances_of($ref_updates, 'PhabricatorRepositoryPushLog');
+
+    $update = head($ref_updates);
+    $type = $this->getRepository()->getVersionControlSystem();
+    switch ($type) {
+      case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
+        return $this->generateGitDiffForReview($update);
+      default:
+        throw new Exception(pht('Unsupported repository type "%s"!', $type));
+    }
+  }
+
+
 
 /* -(  Herald  )------------------------------------------------------------- */
 
@@ -581,6 +640,89 @@
     return $content_updates;
   }
 
+  private function isGitPushForReview(array $ref_updates) {
+    foreach ($ref_updates as $update) {
+      $name = $update->getRefName();
+      if (preg_match('(^review(?:/|\z))', $name)) {
+        if (count($ref_updates) !== 1) {
+          throw new DiffusionCommitHookRejectException(
+            pht(
+              'This push updates several branches, including a virtual branch '.
+              'which triggers code review (%s). When pushing changes for '.
+              'review, you must push to ONLY the virtual review branch.',
+              $name));
+        }
+
+        $update = head($ref_updates);
+
+        $type_branch = PhabricatorRepositoryPushLog::REFTYPE_BRANCH;
+        if ($update->getRefType() != $type_branch) {
+          throw new DiffusionCommitHookRejectException(
+            pht(
+              'This push updates a virtual ref (%s), but does not push a '.
+              'branch to it. Virtual ref names are reserved and can only be '.
+              'used for branches.',
+              $name));
+        }
+
+        $flags = $update->getChangeFlags();
+        $flag_add = PhabricatorRepositoryPushLog::CHANGEFLAG_ADD;
+        $flag_delete = PhabricatorRepositoryPushLog::CHANGEFLAG_DELETE;
+        if ($flags & $flag_delete) {
+          // This is deleting a virtual branch, so let it through as a normal
+          // push. Most likely, this is cleaning up a mistake where a virtual
+          // branch was somehow made concrete.
+          return false;
+        }
+
+        if ($flags !== PhabricatorRepositoryPushLog::CHANGEFLAG_ADD) {
+          throw new DiffusionCommitHookRejectException(
+            pht(
+              'This push updates a virtual branch (%s). Pushes to virtual '.
+              'branches must create them, but this push does not. Usually, '.
+              'this means someone has accidentally created a real branch '.
+              'with this name. Verify the offending branch is safe to '.
+              'delete, remove it, and then try pushing again.',
+              $name));
+        }
+
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  private function generateGitDiffForReview(PhabricatorRepositoryPushLog $ref) {
+    $old = $ref->getMergeBase();
+    $new = $ref->getRefNew();
+
+    // TODO: Duplication with arc.
+    $options = array(
+      // NOTE: This is not in `arc`.
+      '--binary',
+
+      '--no-ext-diff',
+      '--no-textconv',
+      '--no-color',
+      '--src-prefix=a/',
+      '--dst-prefix=b/',
+      '-U32767',
+      '-M',
+      '-C',
+    );
+
+    list($diff) = $this->getRepository()->execxLocalCommand(
+      'diff %Ls %s --',
+      $options,
+      $old.'..'.$new);
+
+    $changes = id(new ArcanistDiffParser())->parseDiff($diff);
+
+    return DifferentialDiff::newFromRawChanges($changes);
+  }
+
+
 /* -(  Custom  )------------------------------------------------------------- */
 
   private function applyCustomHooks(array $updates) {