When a revision changes more than 1,000 files, don't show the changes on the main page

Summary: Depends on D19295. Ref T13110. Degrade the review UX when users try to interact with changes which are too large to receive human review.

Test Plan: Reduced the "very large" limit, browsed some changes, saw various elements degrade.

Maniphest Tasks: T13110

Differential Revision: https://secure.phabricator.com/D19296

src/applications/differential/controller/DifferentialRevisionViewController.php

@@ -3,11 +3,20 @@
 final class DifferentialRevisionViewController extends DifferentialController {
 
   private $revisionID;
+  private $veryLargeDiff;
 
   public function shouldAllowPublic() {
     return true;
   }
 
+  public function isVeryLargeDiff() {
+    return $this->veryLargeDiff;
+  }
+
+  public function getVeryLargeDiffLimit() {
+    return 1000;
+  }
+
   public function handleRequest(AphrontRequest $request) {
     $viewer = $this->getViewer();
     $this->revisionID = $request->getURIData('id');
@@ -73,6 +82,10 @@ final class DifferentialRevisionViewController extends DifferentialController {
         idx($diffs, $diff_vs),
         $repository);
 
+    if (count($rendering_references) > $this->getVeryLargeDiffLimit()) {
+      $this->veryLargeDiff = true;
+    }
+
     if ($request->getExists('download')) {
       return $this->buildRawDiffResponse(
         $revision,
@@ -150,7 +163,7 @@ final class DifferentialRevisionViewController extends DifferentialController {
       $warning->appendChild(hsprintf(
         '%s <strong>%s</strong>',
         pht(
-          'This diff is very large and affects %s files. '.
+          'This diff is large and affects %s files. '.
           'You may load each file individually or ',
           new PhutilNumber($count)),
         phutil_tag(
@@ -265,35 +278,53 @@ final class DifferentialRevisionViewController extends DifferentialController {
 
     $timeline->setQuoteRef($revision->getMonogram());
 
-    $changeset_view = id(new DifferentialChangesetListView())
-      ->setChangesets($changesets)
-      ->setVisibleChangesets($visible_changesets)
-      ->setStandaloneURI('/differential/changeset/')
-      ->setRawFileURIs(
-        '/differential/changeset/?view=old',
-        '/differential/changeset/?view=new')
-      ->setUser($viewer)
-      ->setDiff($target)
-      ->setRenderingReferences($rendering_references)
-      ->setVsMap($vs_map)
-      ->setWhitespace($whitespace)
-      ->setSymbolIndexes($symbol_indexes)
-      ->setTitle(pht('Diff %s', $target->getID()))
-      ->setBackground(PHUIObjectBoxView::BLUE_PROPERTY);
+    if ($this->isVeryLargeDiff()) {
+      $messages = array();
+
+      $messages[] = pht(
+        'This very large diff affects more than %s files. Use the %s to '.
+        'browse changes.',
+        new PhutilNumber($this->getVeryLargeDiffLimit()),
+        phutil_tag(
+          'a',
+          array(
+            'href' => '/differential/diff/'.$target->getID().'/changesets/',
+          ),
+          phutil_tag('strong', array(), pht('Changeset List'))));
+
+      $changeset_view = id(new PHUIInfoView())
+        ->setErrors($messages);
+    } else {
+      $changeset_view = id(new DifferentialChangesetListView())
+        ->setChangesets($changesets)
+        ->setVisibleChangesets($visible_changesets)
+        ->setStandaloneURI('/differential/changeset/')
+        ->setRawFileURIs(
+          '/differential/changeset/?view=old',
+          '/differential/changeset/?view=new')
+        ->setUser($viewer)
+        ->setDiff($target)
+        ->setRenderingReferences($rendering_references)
+        ->setVsMap($vs_map)
+        ->setWhitespace($whitespace)
+        ->setSymbolIndexes($symbol_indexes)
+        ->setTitle(pht('Diff %s', $target->getID()))
+        ->setBackground(PHUIObjectBoxView::BLUE_PROPERTY);
 
 
-    $revision_id = $revision->getID();
-    $inline_list_uri = "/revision/inlines/{$revision_id}/";
-    $inline_list_uri = $this->getApplicationURI($inline_list_uri);
-    $changeset_view->setInlineListURI($inline_list_uri);
+      $revision_id = $revision->getID();
+      $inline_list_uri = "/revision/inlines/{$revision_id}/";
+      $inline_list_uri = $this->getApplicationURI($inline_list_uri);
+      $changeset_view->setInlineListURI($inline_list_uri);
 
-    if ($repository) {
-      $changeset_view->setRepository($repository);
-    }
+      if ($repository) {
+        $changeset_view->setRepository($repository);
+      }
 
-    if (!$viewer_is_anonymous) {
-      $changeset_view->setInlineCommentControllerURI(
-        '/differential/comment/inline/edit/'.$revision->getID().'/');
+      if (!$viewer_is_anonymous) {
+        $changeset_view->setInlineCommentControllerURI(
+          '/differential/comment/inline/edit/'.$revision->getID().'/');
+      }
     }
 
     $broken_diffs = $this->loadHistoryDiffStatus($diffs);
@@ -312,7 +343,7 @@ final class DifferentialRevisionViewController extends DifferentialController {
       ->setLocalCommits(idx($props, 'local:commits'))
       ->setCommitsForLinks($commits_for_links);
 
-    if ($repository) {
+    if ($repository && !$this->isVeryLargeDiff()) {
       $other_revisions = $this->loadOtherRevisions(
         $changesets,
         $target,
@@ -328,10 +359,14 @@ final class DifferentialRevisionViewController extends DifferentialController {
 
     $this->buildPackageMaps($changesets);
 
-    $toc_view = $this->buildTableOfContents(
-      $changesets,
-      $visible_changesets,
-      $target->loadCoverageMap($viewer));
+    if ($this->isVeryLargeDiff()) {
+      $toc_view = null;
+    } else {
+      $toc_view = $this->buildTableOfContents(
+        $changesets,
+        $visible_changesets,
+        $target->loadCoverageMap($viewer));
+    }
 
     // Attach changesets to each reviewer so we can show which Owners package
     // reviewers own no files.
@@ -341,12 +376,17 @@ final class DifferentialRevisionViewController extends DifferentialController {
       $reviewer->attachChangesets($reviewer_changesets);
     }
 
-    $tab_group = id(new PHUITabGroupView())
-      ->addTab(
+    $tab_group = id(new PHUITabGroupView());
+
+    if ($toc_view) {
+      $tab_group->addTab(
         id(new PHUITabView())
           ->setName(pht('Files'))
           ->setKey('files')
-          ->appendChild($toc_view))
+          ->appendChild($toc_view));
+    }
+
+    $tab_group
       ->addTab(
         id(new PHUITabView())
           ->setName(pht('History'))
@@ -479,7 +519,7 @@ final class DifferentialRevisionViewController extends DifferentialController {
       PhabricatorShowFiletreeSetting::VALUE_ENABLE_FILETREE);
 
     $nav = null;
-    if ($filetree_on) {
+    if ($filetree_on && !$this->isVeryLargeDiff()) {
       $collapsed_key = PhabricatorFiletreeVisibleSetting::SETTINGKEY;
       $collapsed_value = $viewer->getUserSetting($collapsed_key);