Fix several issues with email-related global preferences

Summary:
Ref T11098. Mixture of issues here:

  - Similar problem to D16112, where users with no settings at all could fail to fall back to the global defaults.
    - I made `UserPreferencesQuery` responsible for building defaults instead to simplify this, since we have 4 or 5 callsites which need to do it and they aren't easily reducible.
  - Handle cases where `metamta.one-mail-per-recipient` is off (and thus users can not have any custom settings) more explicitly.
  - When `metamta.one-mail-per-recipient` is off, remove the "Email Format" panel for users only -- administrators can still access it in global preferences.

Test Plan:
  - Deleted a user's preferences, changed globals, purged cache, made sure defaults reflected global defaults.
  - Changed global mail tags, sent mail to the user, verified it was dropped in accordinace with global settings.
  - Changed user's settings to get the mail instead, verified mail was sent.
  - Toggled user's Re / Vary settings, verified mail subject lines reflected user settings.
  - Disabled `metamta.one-mail-per-recipient`, verified user "Email Format" panel vanished.
  - Edited "Email Format" in single-mail-mode in global prefs as an administrator.
  - Sent more mail, verified mail respected new global settings.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11098

Differential Revision: https://secure.phabricator.com/D16118

src/applications/feed/PhabricatorFeedStoryPublisher.php

@@ -215,6 +215,7 @@ final class PhabricatorFeedStoryPublisher extends Phobject {
       $all_prefs = id(new PhabricatorUserPreferencesQuery())
         ->setViewer(PhabricatorUser::getOmnipotentUser())
         ->withUserPHIDs($phids)
+        ->needSyntheticPreferences(true)
         ->execute();
       $all_prefs = mpull($all_prefs, null, 'getUserPHID');
     }

src/applications/metamta/storage/PhabricatorMetaMTAMail.php

@@ -877,6 +877,7 @@ final class PhabricatorMetaMTAMail
     $all_prefs = id(new PhabricatorUserPreferencesQuery())
       ->setViewer(PhabricatorUser::getOmnipotentUser())
       ->withUserPHIDs($actor_phids)
+      ->needSyntheticPreferences(true)
       ->execute();
     $all_prefs = mpull($all_prefs, null, 'getUserPHID');
 
@@ -1105,30 +1106,21 @@ final class PhabricatorMetaMTAMail
 
 
   private function loadPreferences($target_phid) {
-    if (!self::shouldMultiplexAllMail()) {
-      $target_phid = null;
-    }
+    $viewer = PhabricatorUser::getOmnipotentUser();
 
-    if ($target_phid) {
+    if (self::shouldMultiplexAllMail()) {
       $preferences = id(new PhabricatorUserPreferencesQuery())
-        ->setViewer(PhabricatorUser::getOmnipotentUser())
+        ->setViewer($viewer)
         ->withUserPHIDs(array($target_phid))
+        ->needSyntheticPreferences(true)
         ->executeOne();
-    } else {
-      $preferences = null;
-    }
-
-    // TODO: Here, we would load global preferences once they exist.
-
-    if (!$preferences) {
-      // If we haven't found suitable preferences yet, return an empty object
-      // which implicitly has all the default values.
-      $preferences = id(new PhabricatorUserPreferences())
-        ->attachUser(new PhabricatorUser());
-    }
-
+      if ($preferences) {
         return $preferences;
       }
+    }
+
+    return PhabricatorUserPreferences::loadGlobalPreferences($viewer);
+  }
 
   private function shouldAddRePrefix(PhabricatorUserPreferences $preferences) {
     $value = $preferences->getSettingValue(

src/applications/people/cache/PhabricatorUserPreferencesCacheType.php

@@ -29,29 +29,16 @@ final class PhabricatorUserPreferencesCacheType
 
     $preferences = id(new PhabricatorUserPreferencesQuery())
       ->setViewer($viewer)
-      ->withUserPHIDs($user_phids)
+      ->withUsers($users)
+      ->needSyntheticPreferences(true)
       ->execute();
     $preferences = mpull($preferences, null, 'getUserPHID');
 
-    // If some users don't have settings of their own yet, we need to load
-    // the global default settings to generate caches for them.
-    if (count($preferences) < count($user_phids)) {
-      $global = id(new PhabricatorUserPreferencesQuery())
-        ->setViewer($viewer)
-        ->withBuiltinKeys(
-          array(
-            PhabricatorUserPreferences::BUILTIN_GLOBAL_DEFAULT,
-          ))
-        ->executeOne();
-    } else {
-      $global = null;
-    }
-
     $all_settings = PhabricatorSetting::getAllSettings();
 
     $settings = array();
     foreach ($users as $user_phid => $user) {
-      $preference = idx($preferences, $user_phid, $global);
+      $preference = idx($preferences, $user_phid);
 
       if (!$preference) {
         continue;

src/applications/settings/controller/PhabricatorSettingsMainController.php

@@ -152,6 +152,10 @@ final class PhabricatorSettingsMainController
         if (!$this->isSelf() && !$panel->isManagementPanel()) {
           continue;
         }
+
+        if ($this->isSelf() && !$panel->isUserPanel()) {
+          continue;
+        }
       }
 
       if (!empty($result[$key])) {

src/applications/settings/panel/PhabricatorEmailFormatSettingsPanel.php

@@ -13,7 +13,15 @@ final class PhabricatorEmailFormatSettingsPanel
     return PhabricatorSettingsEmailPanelGroup::PANELGROUPKEY;
   }
 
+  public function isUserPanel() {
+    return PhabricatorMetaMTAMail::shouldMultiplexAllMail();
+  }
+
   public function isManagementPanel() {
+    if (!$this->isUserPanel()) {
+      return false;
+    }
+
     if ($this->getUser()->getIsMailingList()) {
       return true;
     }

src/applications/settings/panel/PhabricatorSettingsPanel.php

@@ -154,6 +154,18 @@ abstract class PhabricatorSettingsPanel extends Phobject {
   }
 
 
+  /**
+   * Return true if this panel is available to users while editing their own
+   * settings.
+   *
+   * @return bool True to enable management on behalf of a user.
+   * @task config
+   */
+  public function isUserPanel() {
+    return true;
+  }
+
+
   /**
    * Return true if this panel is available to administrators while managing
    * bot and mailing list accounts.

src/applications/settings/query/PhabricatorUserPreferencesQuery.php

@@ -9,6 +9,7 @@ final class PhabricatorUserPreferencesQuery
   private $builtinKeys;
   private $hasUserPHID;
   private $users = array();
+  private $synthetic;
 
   public function withIDs(array $ids) {
     $this->ids = $ids;
@@ -42,12 +43,38 @@ final class PhabricatorUserPreferencesQuery
     return $this;
   }
 
+  /**
+   * Always return preferences for every queried user.
+   *
+   * If no settings exist for a user, a new empty settings object with
+   * appropriate defaults is returned.
+   *
+   * @param bool True to generat synthetic preferences for missing users.
+   */
+  public function needSyntheticPreferences($synthetic) {
+    $this->synthetic = $synthetic;
+    return $this;
+  }
+
   public function newResultObject() {
     return new PhabricatorUserPreferences();
   }
 
   protected function loadPage() {
-    return $this->loadStandardPage($this->newResultObject());
+    $preferences = $this->loadStandardPage($this->newResultObject());
+
+    if ($this->synthetic) {
+      $user_map = mpull($preferences, null, 'getUserPHID');
+      foreach ($this->userPHIDs as $user_phid) {
+        if (isset($user_map[$user_phid])) {
+          continue;
+        }
+        $preferences[] = $this->newResultObject()
+          ->setUserPHID($user_phid);
+      }
+    }
+
+    return $preferences;
   }
 
   protected function willFilterPage(array $prefs) {

src/applications/settings/setting/PhabricatorEmailFormatSetting.php

@@ -20,10 +20,6 @@ final class PhabricatorEmailFormatSetting
     return 100;
   }
 
-  protected function isEnabledForViewer(PhabricatorUser $viewer) {
-    return PhabricatorMetaMTAMail::shouldMultiplexAllMail();
-  }
-
   protected function getControlInstructions() {
     return pht(
       'You can opt to receive plain text email from Phabricator instead '.

src/applications/settings/setting/PhabricatorEmailRePrefixSetting.php

@@ -20,10 +20,6 @@ final class PhabricatorEmailRePrefixSetting
     return 200;
   }
 
-  protected function isEnabledForViewer(PhabricatorUser $viewer) {
-    return PhabricatorMetaMTAMail::shouldMultiplexAllMail();
-  }
-
   protected function getControlInstructions() {
     return pht(
       'The **Add "Re:" Prefix** setting adds "Re:" in front of all messages, '.

src/applications/settings/setting/PhabricatorEmailVarySubjectsSetting.php

@@ -20,10 +20,6 @@ final class PhabricatorEmailVarySubjectsSetting
     return 300;
   }
 
-  protected function isEnabledForViewer(PhabricatorUser $viewer) {
-    return PhabricatorMetaMTAMail::shouldMultiplexAllMail();
-  }
-
   protected function getControlInstructions() {
     return pht(
       'With **Vary Subjects** enabled, most mail subject lines will include '.

src/applications/settings/storage/PhabricatorUserPreferences.php

@@ -122,31 +122,35 @@ final class PhabricatorUserPreferences
    * @param PhabricatorUser User to load or create preferences for.
    */
   public static function loadUserPreferences(PhabricatorUser $user) {
-    $preferences = id(new PhabricatorUserPreferencesQuery())
+    return id(new PhabricatorUserPreferencesQuery())
       ->setViewer($user)
       ->withUsers(array($user))
+      ->needSyntheticPreferences(true)
       ->executeOne();
-    if ($preferences) {
-      return $preferences;
   }
 
-    $preferences = id(new self())
-      ->setUserPHID($user->getPHID())
-      ->attachUser($user);
-
+  /**
+   * Load or create a global preferences object.
+   *
+   * If no global preferences exist, an empty preferences object is returned.
+   *
+   * @param PhabricatorUser Viewing user.
+   */
+  public static function loadGlobalPreferences(PhabricatorUser $viewer) {
     $global = id(new PhabricatorUserPreferencesQuery())
-      ->setViewer($user)
+      ->setViewer($viewer)
       ->withBuiltinKeys(
         array(
           self::BUILTIN_GLOBAL_DEFAULT,
         ))
       ->executeOne();
 
-    if ($global) {
-      $preferences->attachDefaultSettings($global);
+    if (!$global) {
+      $global = id(new self())
+        ->attachUser(new PhabricatorUser());
     }
 
-    return $preferences;
+    return $global;
   }
 
   public function newTransaction($key, $value) {