Add a preference to disable ghost comments

Summary: Ref T7447. At least some users dislike this feature so strongly that they'd prefer not to have it at all.

Test Plan: Viewed ghosts; toggled preference, no more ghosts.

Reviewers: chad

Reviewed By: chad

Subscribers: yelirekim, epriestley

Maniphest Tasks: T7447

Differential Revision: https://secure.phabricator.com/D12704

src/applications/differential/query/DifferentialInlineCommentQuery.php

@@ -148,6 +148,13 @@ final class DifferentialInlineCommentQuery
     assert_instances_of($new, 'DifferentialChangeset');
 
     $viewer = $this->getViewer();
+
+    $pref = $viewer->loadPreferences()->getPreference(
+      PhabricatorUserPreferences::PREFERENCE_DIFF_GHOSTS);
+    if ($pref == 'disabled') {
+      return $inlines;
+    }
+
     $all = array_merge($old, $new);
 
     $changeset_ids = mpull($inlines, 'getChangesetID');

src/applications/settings/panel/PhabricatorDiffPreferencesSettingsPanel.php

@@ -20,6 +20,7 @@ final class PhabricatorDiffPreferencesSettingsPanel
     $preferences = $user->loadPreferences();
 
     $pref_unified = PhabricatorUserPreferences::PREFERENCE_DIFF_UNIFIED;
+    $pref_ghosts = PhabricatorUserPreferences::PREFERENCE_DIFF_GHOSTS;
     $pref_filetree = PhabricatorUserPreferences::PREFERENCE_DIFF_FILETREE;
 
     if ($request->isFormPost()) {
@@ -36,6 +37,9 @@ final class PhabricatorDiffPreferencesSettingsPanel
       $unified = $request->getStr($pref_unified);
       $preferences->setPreference($pref_unified, $unified);
 
+      $ghosts = $request->getStr($pref_ghosts);
+      $preferences->setPreference($pref_ghosts, $ghosts);
+
       $preferences->save();
       return id(new AphrontRedirectResponse())
         ->setURI($this->getPanelURI('?saved=true'));
@@ -60,6 +64,16 @@ final class PhabricatorDiffPreferencesSettingsPanel
               'default' => pht('On Small Screens'),
               'unified' => pht('Always'),
             )))
+      ->appendChild(
+        id(new AphrontFormSelectControl())
+          ->setLabel(pht('Show Older Inlines'))
+          ->setName($pref_ghosts)
+          ->setValue($preferences->getPreference($pref_ghosts))
+          ->setOptions(
+            array(
+              'default' => pht('Enabled'),
+              'disabled' => pht('Disabled'),
+            )))
       ->appendChild(
         id(new AphrontFormSelectControl())
           ->setLabel(pht('Show Filetree'))

src/applications/settings/storage/PhabricatorUserPreferences.php

@@ -31,6 +31,7 @@ final class PhabricatorUserPreferences extends PhabricatorUserDAO {
 
   const PREFERENCE_DIFF_UNIFIED         = 'diff-unified';
   const PREFERENCE_DIFF_FILETREE        = 'diff-filetree';
+  const PREFERENCE_DIFF_GHOSTS = 'diff-ghosts';
 
   const PREFERENCE_CONPH_NOTIFICATIONS = 'conph-notifications';
   const PREFERENCE_CONPHERENCE_COLUMN = 'conpherence-column';