Modernize Hovercard implementation

Summary:
Ref T8980. Move away from events to EngineExtensions.

This also simplifies hovercards a bit:

  - Removes tasks from revision cards.
  - Removes blockers/blocked from task cards.
  - Removes "Send Message" from user cards.

These mostly felt cluttery to me. Open to arguments to retain them. I think we can make better use of the space, though (e.g., flags, projects + board columns).

Test Plan:
  - Viewed people, task, revision, commit and project hovercards.

{F1043256}

{F1043257}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T8980

Differential Revision: https://secure.phabricator.com/D14878

resources/celerity/map.php

@@ -8,7 +8,7 @@
 return array(
   'names' => array(
     'core.pkg.css' => 'a419cf4b',
-    'core.pkg.js' => 'cf262309',
+    'core.pkg.js' => 'b826f522',
     'darkconsole.pkg.js' => 'e7393ebb',
     'differential.pkg.css' => '2de124c9',
     'differential.pkg.js' => '64e69521',
@@ -452,7 +452,7 @@ return array(
     'rsrc/js/core/DragAndDropFileUpload.js' => 'ad10aeac',
     'rsrc/js/core/DraggableList.js' => 'a16ec1c6',
     'rsrc/js/core/FileUpload.js' => '477359c8',
-    'rsrc/js/core/Hovercard.js' => '14ac66f5',
+    'rsrc/js/core/Hovercard.js' => '6914d0dd',
     'rsrc/js/core/KeyboardShortcut.js' => '1ae869f2',
     'rsrc/js/core/KeyboardShortcutManager.js' => 'c1700f6f',
     'rsrc/js/core/MultirowRowManager.js' => 'b5d57730',
@@ -747,7 +747,7 @@ return array(
     'phabricator-file-upload' => '477359c8',
     'phabricator-filetree-view-css' => 'fccf9f82',
     'phabricator-flag-css' => '5337623f',
-    'phabricator-hovercard' => '14ac66f5',
+    'phabricator-hovercard' => '6914d0dd',
     'phabricator-hovercard-view-css' => '1239cd52',
     'phabricator-keyboard-shortcut' => '1ae869f2',
     'phabricator-keyboard-shortcut-manager' => 'c1700f6f',
@@ -935,13 +935,6 @@ return array(
       'javelin-dom',
       'javelin-history',
     ),
-    '14ac66f5' => array(
-      'javelin-install',
-      'javelin-dom',
-      'javelin-vector',
-      'javelin-request',
-      'javelin-uri',
-    ),
     '1ad0a787' => array(
       'javelin-install',
       'javelin-reactor',
@@ -1311,6 +1304,13 @@ return array(
     '6882e80a' => array(
       'javelin-dom',
     ),
+    '6914d0dd' => array(
+      'javelin-install',
+      'javelin-dom',
+      'javelin-vector',
+      'javelin-request',
+      'javelin-uri',
+    ),
     '69adf288' => array(
       'javelin-install',
     ),

src/__phutil_library_map__.php

@@ -262,7 +262,6 @@ phutil_register_library_map(array(
     'ConpherenceEditor' => 'applications/conpherence/editor/ConpherenceEditor.php',
     'ConpherenceFormDragAndDropUploadControl' => 'applications/conpherence/view/ConpherenceFormDragAndDropUploadControl.php',
     'ConpherenceFulltextQuery' => 'applications/conpherence/query/ConpherenceFulltextQuery.php',
-    'ConpherenceHovercardEventListener' => 'applications/conpherence/events/ConpherenceHovercardEventListener.php',
     'ConpherenceImageData' => 'applications/conpherence/constants/ConpherenceImageData.php',
     'ConpherenceIndex' => 'applications/conpherence/storage/ConpherenceIndex.php',
     'ConpherenceLayoutView' => 'applications/conpherence/view/ConpherenceLayoutView.php',
@@ -420,7 +419,7 @@ phutil_register_library_map(array(
     'DifferentialHostField' => 'applications/differential/customfield/DifferentialHostField.php',
     'DifferentialHostedGitLandingStrategy' => 'applications/differential/landing/DifferentialHostedGitLandingStrategy.php',
     'DifferentialHostedMercurialLandingStrategy' => 'applications/differential/landing/DifferentialHostedMercurialLandingStrategy.php',
-    'DifferentialHovercardEventListener' => 'applications/differential/event/DifferentialHovercardEventListener.php',
+    'DifferentialHovercardEngineExtension' => 'applications/differential/engineextension/DifferentialHovercardEngineExtension.php',
     'DifferentialHunk' => 'applications/differential/storage/DifferentialHunk.php',
     'DifferentialHunkParser' => 'applications/differential/parser/DifferentialHunkParser.php',
     'DifferentialHunkParserTestCase' => 'applications/differential/parser/__tests__/DifferentialHunkParserTestCase.php',
@@ -620,7 +619,7 @@ phutil_register_library_map(array(
     'DiffusionHistoryController' => 'applications/diffusion/controller/DiffusionHistoryController.php',
     'DiffusionHistoryQueryConduitAPIMethod' => 'applications/diffusion/conduit/DiffusionHistoryQueryConduitAPIMethod.php',
     'DiffusionHistoryTableView' => 'applications/diffusion/view/DiffusionHistoryTableView.php',
-    'DiffusionHovercardEventListener' => 'applications/diffusion/events/DiffusionHovercardEventListener.php',
+    'DiffusionHovercardEngineExtension' => 'applications/diffusion/engineextension/DiffusionHovercardEngineExtension.php',
     'DiffusionInlineCommentController' => 'applications/diffusion/controller/DiffusionInlineCommentController.php',
     'DiffusionInlineCommentPreviewController' => 'applications/diffusion/controller/DiffusionInlineCommentPreviewController.php',
     'DiffusionLastModifiedController' => 'applications/diffusion/controller/DiffusionLastModifiedController.php',
@@ -1292,7 +1291,7 @@ phutil_register_library_map(array(
     'ManiphestExcelFormatTestCase' => 'applications/maniphest/export/__tests__/ManiphestExcelFormatTestCase.php',
     'ManiphestExportController' => 'applications/maniphest/controller/ManiphestExportController.php',
     'ManiphestGetTaskTransactionsConduitAPIMethod' => 'applications/maniphest/conduit/ManiphestGetTaskTransactionsConduitAPIMethod.php',
-    'ManiphestHovercardEventListener' => 'applications/maniphest/event/ManiphestHovercardEventListener.php',
+    'ManiphestHovercardEngineExtension' => 'applications/maniphest/engineextension/ManiphestHovercardEngineExtension.php',
     'ManiphestInfoConduitAPIMethod' => 'applications/maniphest/conduit/ManiphestInfoConduitAPIMethod.php',
     'ManiphestNameIndex' => 'applications/maniphest/storage/ManiphestNameIndex.php',
     'ManiphestPriorityConfigOptionType' => 'applications/maniphest/config/ManiphestPriorityConfigOptionType.php',
@@ -2370,6 +2369,8 @@ phutil_register_library_map(array(
     'PhabricatorHomeMainController' => 'applications/home/controller/PhabricatorHomeMainController.php',
     'PhabricatorHomePreferencesSettingsPanel' => 'applications/settings/panel/PhabricatorHomePreferencesSettingsPanel.php',
     'PhabricatorHomeQuickCreateController' => 'applications/home/controller/PhabricatorHomeQuickCreateController.php',
+    'PhabricatorHovercardEngineExtension' => 'applications/search/engineextension/PhabricatorHovercardEngineExtension.php',
+    'PhabricatorHovercardEngineExtensionModule' => 'applications/search/engineextension/PhabricatorHovercardEngineExtensionModule.php',
     'PhabricatorHovercardUIExample' => 'applications/uiexample/examples/PhabricatorHovercardUIExample.php',
     'PhabricatorHovercardView' => 'view/widget/hovercard/PhabricatorHovercardView.php',
     'PhabricatorHunksManagementMigrateWorkflow' => 'applications/differential/management/PhabricatorHunksManagementMigrateWorkflow.php',
@@ -2711,7 +2712,7 @@ phutil_register_library_map(array(
     'PhabricatorPeopleDisableController' => 'applications/people/controller/PhabricatorPeopleDisableController.php',
     'PhabricatorPeopleEmpowerController' => 'applications/people/controller/PhabricatorPeopleEmpowerController.php',
     'PhabricatorPeopleExternalPHIDType' => 'applications/people/phid/PhabricatorPeopleExternalPHIDType.php',
-    'PhabricatorPeopleHovercardEventListener' => 'applications/people/event/PhabricatorPeopleHovercardEventListener.php',
+    'PhabricatorPeopleHovercardEngineExtension' => 'applications/people/engineextension/PhabricatorPeopleHovercardEngineExtension.php',
     'PhabricatorPeopleInviteController' => 'applications/people/controller/PhabricatorPeopleInviteController.php',
     'PhabricatorPeopleInviteListController' => 'applications/people/controller/PhabricatorPeopleInviteListController.php',
     'PhabricatorPeopleInviteSendController' => 'applications/people/controller/PhabricatorPeopleInviteSendController.php',
@@ -4172,7 +4173,6 @@ phutil_register_library_map(array(
     'ConpherenceEditor' => 'PhabricatorApplicationTransactionEditor',
     'ConpherenceFormDragAndDropUploadControl' => 'AphrontFormControl',
     'ConpherenceFulltextQuery' => 'PhabricatorOffsetPagedQuery',
-    'ConpherenceHovercardEventListener' => 'PhabricatorEventListener',
     'ConpherenceImageData' => 'ConpherenceConstants',
     'ConpherenceIndex' => 'ConpherenceDAO',
     'ConpherenceLayoutView' => 'AphrontView',
@@ -4347,7 +4347,7 @@ phutil_register_library_map(array(
     'DifferentialHostField' => 'DifferentialCustomField',
     'DifferentialHostedGitLandingStrategy' => 'DifferentialLandingStrategy',
     'DifferentialHostedMercurialLandingStrategy' => 'DifferentialLandingStrategy',
-    'DifferentialHovercardEventListener' => 'PhabricatorEventListener',
+    'DifferentialHovercardEngineExtension' => 'PhabricatorHovercardEngineExtension',
     'DifferentialHunk' => array(
       'DifferentialDAO',
       'PhabricatorPolicyInterface',
@@ -4568,7 +4568,7 @@ phutil_register_library_map(array(
     'DiffusionHistoryController' => 'DiffusionController',
     'DiffusionHistoryQueryConduitAPIMethod' => 'DiffusionQueryConduitAPIMethod',
     'DiffusionHistoryTableView' => 'DiffusionView',
-    'DiffusionHovercardEventListener' => 'PhabricatorEventListener',
+    'DiffusionHovercardEngineExtension' => 'PhabricatorHovercardEngineExtension',
     'DiffusionInlineCommentController' => 'PhabricatorInlineCommentController',
     'DiffusionInlineCommentPreviewController' => 'PhabricatorInlineCommentPreviewController',
     'DiffusionLastModifiedController' => 'DiffusionController',
@@ -5361,7 +5361,7 @@ phutil_register_library_map(array(
     'ManiphestExcelFormatTestCase' => 'PhabricatorTestCase',
     'ManiphestExportController' => 'ManiphestController',
     'ManiphestGetTaskTransactionsConduitAPIMethod' => 'ManiphestConduitAPIMethod',
-    'ManiphestHovercardEventListener' => 'PhabricatorEventListener',
+    'ManiphestHovercardEngineExtension' => 'PhabricatorHovercardEngineExtension',
     'ManiphestInfoConduitAPIMethod' => 'ManiphestConduitAPIMethod',
     'ManiphestNameIndex' => 'ManiphestDAO',
     'ManiphestPriorityConfigOptionType' => 'PhabricatorConfigJSONOptionType',
@@ -6624,6 +6624,8 @@ phutil_register_library_map(array(
     'PhabricatorHomeMainController' => 'PhabricatorHomeController',
     'PhabricatorHomePreferencesSettingsPanel' => 'PhabricatorSettingsPanel',
     'PhabricatorHomeQuickCreateController' => 'PhabricatorHomeController',
+    'PhabricatorHovercardEngineExtension' => 'Phobject',
+    'PhabricatorHovercardEngineExtensionModule' => 'PhabricatorConfigModule',
     'PhabricatorHovercardUIExample' => 'PhabricatorUIExample',
     'PhabricatorHovercardView' => 'AphrontView',
     'PhabricatorHunksManagementMigrateWorkflow' => 'PhabricatorHunksManagementWorkflow',
@@ -7010,7 +7012,7 @@ phutil_register_library_map(array(
     'PhabricatorPeopleDisableController' => 'PhabricatorPeopleController',
     'PhabricatorPeopleEmpowerController' => 'PhabricatorPeopleController',
     'PhabricatorPeopleExternalPHIDType' => 'PhabricatorPHIDType',
-    'PhabricatorPeopleHovercardEventListener' => 'PhabricatorEventListener',
+    'PhabricatorPeopleHovercardEngineExtension' => 'PhabricatorHovercardEngineExtension',
     'PhabricatorPeopleInviteController' => 'PhabricatorPeopleController',
     'PhabricatorPeopleInviteListController' => 'PhabricatorPeopleInviteController',
     'PhabricatorPeopleInviteSendController' => 'PhabricatorPeopleInviteController',

src/applications/conpherence/application/PhabricatorConpherenceApplication.php

@@ -28,12 +28,6 @@ final class PhabricatorConpherenceApplication extends PhabricatorApplication {
     );
   }
 
-  public function getEventListeners() {
-    return array(
-      new ConpherenceHovercardEventListener(),
-    );
-  }
-
   public function getRoutes() {
     return array(
       '/Z(?P<id>[1-9]\d*)'         => 'ConpherenceViewController',

src/applications/conpherence/events/ConpherenceHovercardEventListener.php

@@ -1,41 +0,0 @@
-<?php
-
-/**
- * This event listener is tasked with probably one of the most important
- * missions in this world: Adding a Conpherence button to a hovercard.
- *
- * Handle with care when modifying!
- *
- * @task event
- */
-final class ConpherenceHovercardEventListener extends PhabricatorEventListener {
-
-  public function register() {
-    $this->listen(PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD);
-  }
-
-  public function handleEvent(PhutilEvent $event) {
-    switch ($event->getType()) {
-      case PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD:
-        $this->handleHovercardEvent($event);
-      break;
-    }
-  }
-
-  private function handleHovercardEvent($event) {
-    $hovercard = $event->getValue('hovercard');
-    $user = $event->getValue('object');
-
-    if (!($user instanceof PhabricatorUser)) {
-      return;
-    }
-
-    $conpherence_uri = id(new PhutilURI('/conpherence/new/'))
-      ->setQueryParam('participant', $user->getPHID());
-    $name = pht('Send a Message');
-    $hovercard->addAction($name, $conpherence_uri, true);
-
-    $event->setValue('hovercard', $hovercard);
-  }
-
-}

src/applications/differential/application/PhabricatorDifferentialApplication.php

@@ -44,7 +44,6 @@ final class PhabricatorDifferentialApplication extends PhabricatorApplication {
   public function getEventListeners() {
     return array(
       new DifferentialActionMenuEventListener(),
-      new DifferentialHovercardEventListener(),
       new DifferentialLandingActionMenuEventListener(),
     );
   }

src/applications/differential/engineextension/DifferentialHovercardEngineExtension.php

@@ -0,0 +1,77 @@
+<?php
+
+final class DifferentialHovercardEngineExtension
+  extends PhabricatorHovercardEngineExtension {
+
+  const EXTENSIONKEY = 'differential';
+
+  public function isExtensionEnabled() {
+    return PhabricatorApplication::isClassInstalled(
+      'PhabricatorDifferentialApplication');
+  }
+
+  public function getExtensionName() {
+    return pht('Differential Revisions');
+  }
+
+  public function canRenderObjectHovercard($object) {
+    return ($object instanceof DifferentialRevision);
+  }
+
+  public function willRenderHovercards(array $objects) {
+    $viewer = $this->getViewer();
+    $phids = mpull($objects, 'getPHID');
+
+    $revisions = id(new DifferentialRevisionQuery())
+      ->setViewer($viewer)
+      ->withPHIDs($phids)
+      ->needReviewerStatus(true)
+      ->execute();
+    $revisions = mpull($revisions, null, 'getPHID');
+
+    return array(
+      'revisions' => $revisions,
+    );
+  }
+
+  public function renderHovercard(
+    PhabricatorHovercardView $hovercard,
+    PhabricatorObjectHandle $handle,
+    $object,
+    $data) {
+
+    $viewer = $this->getViewer();
+
+    $revision = idx($data['revisions'], $object->getPHID());
+    if (!$revision) {
+      return;
+    }
+
+    $hovercard->setTitle('D'.$revision->getID());
+    $hovercard->setDetail($revision->getTitle());
+
+    $hovercard->addField(
+      pht('Author'),
+      $viewer->renderHandle($revision->getAuthorPHID()));
+
+    $reviewer_phids = $revision->getReviewerStatus();
+    $reviewer_phids = mpull($reviewer_phids, 'getReviewerPHID');
+
+    $hovercard->addField(
+      pht('Reviewers'),
+      $viewer->renderHandleList($reviewer_phids)->setAsInline(true));
+
+    $summary = $revision->getSummary();
+    if (strlen($summary)) {
+      $summary = id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs(120)
+        ->truncateString($summary);
+
+      $hovercard->addField(pht('Summary'), $summary);
+    }
+
+    $tag = DifferentialRevisionDetailView::renderTagForRevision($revision);
+    $hovercard->addTag($tag);
+  }
+
+}

src/applications/differential/event/DifferentialHovercardEventListener.php

@@ -1,71 +0,0 @@
-<?php
-
-final class DifferentialHovercardEventListener
-  extends PhabricatorEventListener {
-
-  public function register() {
-    $this->listen(PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD);
-  }
-
-  public function handleEvent(PhutilEvent $event) {
-    switch ($event->getType()) {
-      case PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD:
-        $this->handleHovercardEvent($event);
-      break;
-    }
-  }
-
-  private function handleHovercardEvent($event) {
-    $viewer = $event->getUser();
-    $hovercard = $event->getValue('hovercard');
-    $object_handle = $event->getValue('handle');
-    $phid = $object_handle->getPHID();
-    $rev = $event->getValue('object');
-
-    if (!($rev instanceof DifferentialRevision)) {
-      return;
-    }
-
-    $rev->loadRelationships();
-    $reviewer_phids = $rev->getReviewers();
-    $e_task = DifferentialRevisionHasTaskEdgeType::EDGECONST;
-    $edge_query = id(new PhabricatorEdgeQuery())
-      ->withSourcePHIDs(array($phid))
-      ->withEdgeTypes(
-        array(
-          $e_task,
-        ));
-    $edge_query->execute();
-    $tasks = $edge_query->getDestinationPHIDs();
-
-    $hovercard->setTitle('D'.$rev->getID());
-    $hovercard->setDetail($rev->getTitle());
-
-    $hovercard->addField(
-      pht('Author'),
-      $viewer->renderHandle($rev->getAuthorPHID()));
-
-    $hovercard->addField(
-      pht('Reviewers'),
-      $viewer->renderHandleList($reviewer_phids)->setAsInline(true));
-
-    if ($tasks) {
-      $hovercard->addField(
-        pht('Tasks'),
-        $viewer->renderHandleList($tasks)->setAsInline(true));
-    }
-
-    if ($rev->getSummary()) {
-      $hovercard->addField(pht('Summary'),
-        id(new PhutilUTF8StringTruncator())
-        ->setMaximumGlyphs(120)
-        ->truncateString($rev->getSummary()));
-    }
-
-    $hovercard->addTag(
-      DifferentialRevisionDetailView::renderTagForRevision($rev));
-
-    $event->setValue('hovercard', $hovercard);
-  }
-
-}

src/applications/diffusion/application/PhabricatorDiffusionApplication.php

@@ -37,12 +37,6 @@ final class PhabricatorDiffusionApplication extends PhabricatorApplication {
     );
   }
 
-  public function getEventListeners() {
-    return array(
-      new DiffusionHovercardEventListener(),
-    );
-  }
-
   public function getRemarkupRules() {
     return array(
       new DiffusionCommitRemarkupRule(),

src/applications/diffusion/engineextension/DiffusionHovercardEngineExtension.php

@@ -0,0 +1,53 @@
+<?php
+
+final class DiffusionHovercardEngineExtension
+  extends PhabricatorHovercardEngineExtension {
+
+  const EXTENSIONKEY = 'diffusion';
+
+  public function isExtensionEnabled() {
+    return PhabricatorApplication::isClassInstalled(
+      'PhabricatorDiffusionApplication');
+  }
+
+  public function getExtensionName() {
+    return pht('Diffusion Commits');
+  }
+
+  public function canRenderObjectHovercard($object) {
+    return ($object instanceof PhabricatorRepositoryCommit);
+  }
+
+  public function renderHovercard(
+    PhabricatorHovercardView $hovercard,
+    PhabricatorObjectHandle $handle,
+    $commit,
+    $data) {
+
+    $viewer = $this->getViewer();
+
+    $author_phid = $commit->getAuthorPHID();
+    if ($author_phid) {
+      $author = $viewer->loadHandle($author)->renderLink();
+    } else {
+      $commit_data = $commit->loadCommitData();
+      $author = phutil_tag('em', array(), $commit_data->getAuthorName());
+    }
+
+    $hovercard->setTitle($handle->getName());
+    $hovercard->setDetail($commit->getSummary());
+
+    $hovercard->addField(pht('Author'), $author);
+    $hovercard->addField(pht('Date'),
+      phabricator_date($commit->getEpoch(), $viewer));
+
+    if ($commit->getAuditStatus() !=
+      PhabricatorAuditCommitStatusConstants::NONE) {
+
+      $hovercard->addField(pht('Audit Status'),
+        PhabricatorAuditCommitStatusConstants::getStatusName(
+          $commit->getAuditStatus()));
+    }
+  }
+
+}

src/applications/diffusion/events/DiffusionHovercardEventListener.php

@@ -1,75 +0,0 @@
-<?php
-
-final class DiffusionHovercardEventListener extends PhabricatorEventListener {
-
-  public function register() {
-    $this->listen(PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD);
-  }
-
-  public function handleEvent(PhutilEvent $event) {
-    switch ($event->getType()) {
-      case PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD:
-        $this->handleHovercardEvent($event);
-      break;
-    }
-  }
-
-  private function handleHovercardEvent($event) {
-    $viewer = $event->getUser();
-    $hovercard = $event->getValue('hovercard');
-    $object_handle = $event->getValue('handle');
-    $commit = $event->getValue('object');
-
-    if (!($commit instanceof PhabricatorRepositoryCommit)) {
-      return;
-    }
-
-    $commit_data = $commit->loadCommitData();
-
-    $revision = PhabricatorEdgeQuery::loadDestinationPHIDs(
-      $commit->getPHID(),
-      DiffusionCommitHasRevisionEdgeType::EDGECONST);
-    $revision = reset($revision);
-
-    $author = $commit->getAuthorPHID();
-
-    $phids = array_filter(array(
-      $revision,
-      $author,
-    ));
-
-    $handles = id(new PhabricatorHandleQuery())
-      ->setViewer($viewer)
-      ->withPHIDs($phids)
-      ->execute();
-
-    if ($author) {
-      $author = $handles[$author]->renderLink();
-    } else {
-      $author = phutil_tag('em', array(), $commit_data->getAuthorName());
-    }
-
-    $hovercard->setTitle($object_handle->getName());
-    $hovercard->setDetail($commit->getSummary());
-
-    $hovercard->addField(pht('Author'), $author);
-    $hovercard->addField(pht('Date'),
-      phabricator_date($commit->getEpoch(), $viewer));
-
-    if ($commit->getAuditStatus() !=
-      PhabricatorAuditCommitStatusConstants::NONE) {
-
-      $hovercard->addField(pht('Audit Status'),
-        PhabricatorAuditCommitStatusConstants::getStatusName(
-          $commit->getAuditStatus()));
-    }
-
-    if ($revision) {
-      $rev_handle = $handles[$revision];
-      $hovercard->addField(pht('Revision'), $rev_handle->renderLink());
-    }
-
-    $event->setValue('hovercard', $hovercard);
-  }
-
-}

src/applications/maniphest/application/PhabricatorManiphestApplication.php

@@ -36,12 +36,6 @@ final class PhabricatorManiphestApplication extends PhabricatorApplication {
     );
   }
 
-  public function getEventListeners() {
-    return array(
-      new ManiphestHovercardEventListener(),
-    );
-  }
-
   public function getRemarkupRules() {
     return array(
       new ManiphestRemarkupRule(),

src/applications/maniphest/engineextension/ManiphestHovercardEngineExtension.php

@@ -0,0 +1,47 @@
+<?php
+
+final class ManiphestHovercardEngineExtension
+  extends PhabricatorHovercardEngineExtension {
+
+  const EXTENSIONKEY = 'maniphest';
+
+  public function isExtensionEnabled() {
+    return PhabricatorApplication::isClassInstalled(
+      'PhabricatorManiphestApplication');
+  }
+
+  public function getExtensionName() {
+    return pht('Maniphest Tasks');
+  }
+
+  public function canRenderObjectHovercard($object) {
+    return ($object instanceof ManiphestTask);
+  }
+
+  public function renderHovercard(
+    PhabricatorHovercardView $hovercard,
+    PhabricatorObjectHandle $handle,
+    $task,
+    $data) {
+    $viewer = $this->getViewer();
+
+    $hovercard
+      ->setTitle($task->getMonogram())
+      ->setDetail($task->getTitle());
+
+    $owner_phid = $task->getOwnerPHID();
+    if ($owner_phid) {
+      $owner = $viewer->renderHandle($owner_phid);
+    } else {
+      $owner = phutil_tag('em', array(), pht('None'));
+    }
+    $hovercard->addField(pht('Assigned To'), $owner);
+
+    $hovercard->addField(
+      pht('Priority'),
+      ManiphestTaskPriority::getTaskPriorityName($task->getPriority()));
+
+    $hovercard->addTag(ManiphestView::renderTagForTask($task));
+  }
+
+}

src/applications/maniphest/event/ManiphestHovercardEventListener.php

@@ -1,93 +0,0 @@
-<?php
-
-final class ManiphestHovercardEventListener extends PhabricatorEventListener {
-
-  public function register() {
-    $this->listen(PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD);
-  }
-
-  public function handleEvent(PhutilEvent $event) {
-    switch ($event->getType()) {
-      case PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD:
-        $this->handleHovercardEvent($event);
-      break;
-    }
-  }
-
-  private function handleHovercardEvent(PhutilEvent $event) {
-    $viewer = $event->getUser();
-    $hovercard = $event->getValue('hovercard');
-    $handle = $event->getValue('handle');
-    $phid = $handle->getPHID();
-    $task = $event->getValue('object');
-
-    if (!($task instanceof ManiphestTask)) {
-      return;
-    }
-
-    $e_project = PhabricatorProjectObjectHasProjectEdgeType::EDGECONST;
-    // Fun with "Unbeta Pholio", hua hua
-    $e_dep_on = ManiphestTaskDependsOnTaskEdgeType::EDGECONST;
-    $e_dep_by = ManiphestTaskDependedOnByTaskEdgeType::EDGECONST;
-
-    $edge_query = id(new PhabricatorEdgeQuery())
-      ->withSourcePHIDs(array($phid))
-      ->withEdgeTypes(
-        array(
-          $e_project,
-          $e_dep_on,
-          $e_dep_by,
-        ));
-    $edges = idx($edge_query->execute(), $phid);
-    $edge_phids = $edge_query->getDestinationPHIDs();
-
-    $owner_phid = $task->getOwnerPHID();
-
-    $hovercard
-      ->setTitle(pht('T%d', $task->getID()))
-      ->setDetail($task->getTitle());
-
-    if ($owner_phid) {
-      $owner = $viewer->renderHandle($owner_phid);
-    } else {
-      $owner = phutil_tag('em', array(), pht('None'));
-    }
-    $hovercard->addField(pht('Assigned To'), $owner);
-    $hovercard->addField(
-      pht('Priority'),
-      ManiphestTaskPriority::getTaskPriorityName($task->getPriority()));
-
-    if ($edge_phids) {
-      $edge_types = array(
-        $e_project => pht('Projects'),
-        $e_dep_by => pht('Blocks'),
-        $e_dep_on  => pht('Blocked By'),
-      );
-
-      $max_count = 6;
-      foreach ($edge_types as $edge_type => $edge_name) {
-        if ($edges[$edge_type]) {
-          // TODO: This can be made more sophisticated. We still load all
-          // edges into memory. Only load the ones we need.
-          $edge_overflow = array();
-          if (count($edges[$edge_type]) > $max_count) {
-            $edges[$edge_type] = array_slice($edges[$edge_type], 0, 6, true);
-            $edge_overflow = ', ...';
-          }
-
-          $hovercard->addField(
-            $edge_name,
-            array(
-              $viewer->renderHandleList(array_keys($edges[$edge_type])),
-              $edge_overflow,
-            ));
-        }
-      }
-    }
-
-    $hovercard->addTag(ManiphestView::renderTagForTask($task));
-
-    $event->setValue('hovercard', $hovercard);
-  }
-
-}

src/applications/people/application/PhabricatorPeopleApplication.php

@@ -34,12 +34,6 @@ final class PhabricatorPeopleApplication extends PhabricatorApplication {
     return false;
   }
 
-  public function getEventListeners() {
-    return array(
-      new PhabricatorPeopleHovercardEventListener(),
-    );
-  }
-
   public function getRoutes() {
     return array(
       '/people/' => array(

src/applications/people/engineextension/PhabricatorPeopleHovercardEngineExtension.php

@@ -1,45 +1,58 @@
 <?php
 
-final class PhabricatorPeopleHovercardEventListener
+final class PhabricatorPeopleHovercardEngineExtension
-  extends PhabricatorEventListener {
+  extends PhabricatorHovercardEngineExtension {
 
-  public function register() {
+  const EXTENSIONKEY = 'people';
-    $this->listen(PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD);
+
+  public function isExtensionEnabled() {
+    return true;
   }
 
-  public function handleEvent(PhutilEvent $event) {
+  public function getExtensionName() {
-    switch ($event->getType()) {
+    return pht('User Accounts');
-      case PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD:
-        $this->handleHovercardEvent($event);
-      break;
-    }
   }
 
-  private function handleHovercardEvent($event) {
+  public function canRenderObjectHovercard($object) {
-    $viewer = $event->getUser();
+    return ($object instanceof PhabricatorUser);
-    $hovercard = $event->getValue('hovercard');
+  }
-    $object_handle = $event->getValue('handle');
-    $phid = $object_handle->getPHID();
-    $user = $event->getValue('object');
 
-    if (!($user instanceof PhabricatorUser)) {
+  public function willRenderHovercards(array $objects) {
-      return;
+    $viewer = $this->getViewer();
-    }
+    $phids = mpull($objects, 'getPHID');
 
-    // Reload to get availability.
+    $users = id(new PhabricatorPeopleQuery())
-    $user = id(new PhabricatorPeopleQuery())
       ->setViewer($viewer)
-      ->withIDs(array($user->getID()))
+      ->withPHIDs($phids)
       ->needAvailability(true)
       ->needProfile(true)
       ->needBadges(true)
-      ->executeOne();
+      ->execute();
+    $users = mpull($users, null, 'getPHID');
+
+    return array(
+      'users' => $users,
+    );
+  }
+
+  public function renderHovercard(
+    PhabricatorHovercardView $hovercard,
+    PhabricatorObjectHandle $handle,
+    $object,
+    $data) {
+    $viewer = $this->getViewer();
+
+    $user = idx($data['users'], $object->getPHID());
+    if (!$user) {
+      return;
+    }
 
     $hovercard->setTitle($user->getUsername());
+
     $profile = $user->getUserProfile();
     $detail = $user->getRealName();
     if ($profile->getTitle()) {
-      $detail .= ' - '.$profile->getTitle().'.';
+      $detail .= ' - '.$profile->getTitle();
     }
     $hovercard->setDetail($detail);
 
@@ -70,8 +83,6 @@ final class PhabricatorPeopleHovercardEventListener
     foreach ($badges as $badge) {
       $hovercard->addBadge($badge);
     }
-
-    $event->setValue('hovercard', $hovercard);
   }
 
   private function buildBadges(
@@ -101,5 +112,4 @@ final class PhabricatorPeopleHovercardEventListener
     return $items;
   }
 
-
 }

src/applications/search/application/PhabricatorSearchApplication.php

@@ -35,7 +35,7 @@ final class PhabricatorSearchApplication extends PhabricatorApplication {
         'select/(?P<type>\w+)/(?:(?P<action>\w+)/)?'
           => 'PhabricatorSearchSelectController',
         'index/(?P<phid>[^/]+)/' => 'PhabricatorSearchIndexController',
-        'hovercard/(?P<mode>retrieve|test)/'
+        'hovercard/'
           => 'PhabricatorSearchHovercardController',
         'edit/(?P<queryKey>[^/]+)/' => 'PhabricatorSearchEditController',
         'delete/(?P<queryKey>[^/]+)/(?P<engine>[^/]+)/'

src/applications/search/controller/PhabricatorSearchHovercardController.php

@@ -15,13 +15,43 @@ final class PhabricatorSearchHovercardController
       ->setViewer($viewer)
       ->withPHIDs($phids)
       ->execute();
+
     $objects = id(new PhabricatorObjectQuery())
       ->setViewer($viewer)
       ->withPHIDs($phids)
       ->execute();
+    $objects = mpull($objects, null, 'getPHID');
+
+    $extensions =
+      PhabricatorHovercardEngineExtension::getAllEnabledExtensions();
+
+    $extension_maps = array();
+    foreach ($extensions as $key => $extension) {
+      $extension->setViewer($viewer);
+
+      $extension_phids = array();
+      foreach ($objects as $phid => $object) {
+        if ($extension->canRenderObjectHovercard($object)) {
+          $extension_phids[$phid] = $phid;
+        }
+      }
+
+      $extension_maps[$key] = $extension_phids;
+    }
+
+    $extension_data = array();
+    foreach ($extensions as $key => $extension) {
+      $extension_phids = $extension_maps[$key];
+      if (!$extension_phids) {
+        unset($extensions[$key]);
+        continue;
+      }
+
+      $extension_data[$key] = $extension->willRenderHovercards(
+        array_select_keys($objects, $extension_phids));
+    }
 
     $cards = array();
-
     foreach ($phids as $phid) {
       $handle = $handles[$phid];
       $object = $objects[$phid];
@@ -32,43 +62,39 @@ final class PhabricatorSearchHovercardController
 
       if ($object) {
         $hovercard->setObject($object);
-      }
 
-      // Send it to the other side of the world, thanks to PhutilEventEngine
+        foreach ($extension_maps as $key => $extension_phids) {
-      $event = new PhabricatorEvent(
+          if (isset($extension_phids[$phid])) {
-        PhabricatorEventType::TYPE_UI_DIDRENDERHOVERCARD,
+            $extensions[$key]->renderHovercard(
-        array(
+              $hovercard,
-          'hovercard' => $hovercard,
+              $handle,
-          'handle'    => $handle,
+              $object,
-          'object'    => $object,
+              $extension_data[$key]);
-        ));
+          }
-      $event->setUser($viewer);
+        }
-      PhutilEventEngine::dispatchEvent($event);
+      }
 
       $cards[$phid] = $hovercard;
     }
 
-    // Browser-friendly for non-Ajax requests
+    if ($request->isAjax()) {
-    if (!$request->isAjax()) {
-      foreach ($cards as $key => $hovercard) {
-        $cards[$key] = phutil_tag('div',
-          array(
-            'class' => 'ml',
-          ),
-          $hovercard);
-      }
-
-      return $this->buildApplicationPage(
-        $cards,
-        array(
-          'device' => false,
-        ));
-    } else {
       return id(new AphrontAjaxResponse())->setContent(
         array(
           'cards' => $cards,
         ));
     }
+
+    foreach ($cards as $key => $hovercard) {
+      $cards[$key] = phutil_tag('div',
+        array(
+          'class' => 'ml',
+        ),
+        $hovercard);
+    }
+
+    return $this->newPage()
+      ->appendChild($cards)
+      ->setShowFooter(false);
   }
 
 }

src/applications/search/engineextension/PhabricatorHovercardEngineExtension.php

@@ -0,0 +1,60 @@
+<?php
+
+abstract class PhabricatorHovercardEngineExtension extends Phobject {
+
+  private $viewer;
+
+  final public function getExtensionKey() {
+    return $this->getPhobjectClassConstant('EXTENSIONKEY');
+  }
+
+  final public function setViewer($viewer) {
+    $this->viewer = $viewer;
+    return $this;
+  }
+
+  final public function getViewer() {
+    return $this->viewer;
+  }
+
+  abstract public function isExtensionEnabled();
+
+  abstract public function getExtensionName();
+
+  abstract public function canRenderObjectHovercard($object);
+
+  public function getExtensionOrder() {
+    return 5000;
+  }
+
+  public function willRenderHovercards(array $objects) {
+    return null;
+  }
+
+  abstract public function renderHovercard(
+    PhabricatorHovercardView $hovercard,
+    PhabricatorObjectHandle $handle,
+    $object,
+    $data);
+
+  final public static function getAllExtensions() {
+    return id(new PhutilClassMapQuery())
+      ->setAncestorClass(__CLASS__)
+      ->setUniqueMethod('getExtensionKey')
+      ->setSortMethod('getExtensionOrder')
+      ->execute();
+  }
+
+  final public static function getAllEnabledExtensions() {
+    $extensions = self::getAllExtensions();
+
+    foreach ($extensions as $key => $extension) {
+      if (!$extension->isExtensionEnabled()) {
+        unset($extensions[$key]);
+      }
+    }
+
+    return $extensions;
+  }
+
+}

src/applications/search/engineextension/PhabricatorHovercardEngineExtensionModule.php

@@ -0,0 +1,55 @@
+<?php
+
+final class PhabricatorHovercardEngineExtensionModule
+  extends PhabricatorConfigModule {
+
+  public function getModuleKey() {
+    return 'hovercardengine';
+  }
+
+  public function getModuleName() {
+    return pht('Engine: Hovercards');
+  }
+
+  public function renderModuleStatus(AphrontRequest $request) {
+    $viewer = $request->getViewer();
+
+    $extensions = PhabricatorHovercardEngineExtension::getAllExtensions();
+
+    $rows = array();
+    foreach ($extensions as $extension) {
+      $rows[] = array(
+        $extension->getExtensionOrder(),
+        $extension->getExtensionKey(),
+        get_class($extension),
+        $extension->getExtensionName(),
+        $extension->isExtensionEnabled()
+          ? pht('Yes')
+          : pht('No'),
+      );
+    }
+
+    $table = id(new AphrontTableView($rows))
+      ->setHeaders(
+        array(
+          pht('Order'),
+          pht('Key'),
+          pht('Class'),
+          pht('Name'),
+          pht('Enabled'),
+        ))
+      ->setColumnClasses(
+        array(
+          null,
+          null,
+          null,
+          'wide pri',
+          null,
+        ));
+
+    return id(new PHUIObjectBoxView())
+      ->setHeaderText(pht('HovercardEngine Extensions'))
+      ->setTable($table);
+  }
+
+}

src/infrastructure/events/constant/PhabricatorEventType.php

@@ -20,8 +20,6 @@ final class PhabricatorEventType extends PhutilEventType {
   const TYPE_UI_DIDRENDEROBJECTS            = 'ui.didRenderObjects';
   const TYPE_UI_WILLRENDERPROPERTIES        = 'ui.willRenderProperties';
 
-  const TYPE_UI_DIDRENDERHOVERCARD          = 'ui.didRenderHovercard';
-
   const TYPE_PEOPLE_DIDRENDERMENU           = 'people.didRenderMenu';
   const TYPE_AUTH_WILLREGISTERUSER          = 'auth.willRegisterUser';
   const TYPE_AUTH_WILLLOGINUSER             = 'auth.willLoginUser';

webroot/rsrc/js/core/Hovercard.js

@@ -15,7 +15,7 @@ JX.install('Hovercard', {
     _activeRoot : null,
     _visiblePHID : null,
 
-    fetchUrl : '/search/hovercard/retrieve/',
+    fetchUrl : '/search/hovercard/',
 
     /**
      * Hovercard storage. {"PHID-XXXX-YYYY":"<...>", ...}