diff --git a/resources/sql/autopatches/20181031.board.01.queryreset.php b/resources/sql/autopatches/20181031.board.01.queryreset.php
new file mode 100644
index 0000000000..781cf456ce
--- /dev/null
+++ b/resources/sql/autopatches/20181031.board.01.queryreset.php
@@ -0,0 +1,50 @@
+<?php
+
+// See T13208. It was previously possible to replace a saved query with another
+// saved query, causing loss of the first query. Find projects which have their
+// default query set to an invalid query and throw the setting away.
+
+$viewer = PhabricatorUser::getOmnipotentUser();
+
+$table = new PhabricatorProject();
+$conn = $table->establishConnection('w');
+
+$iterator = new LiskMigrationIterator($table);
+$search_engine = id(new ManiphestTaskSearchEngine())
+  ->setViewer($viewer);
+
+foreach ($iterator as $project) {
+  $default_filter = $project->getDefaultWorkboardFilter();
+  if (!strlen($default_filter)) {
+    continue;
+  }
+
+  if ($search_engine->isBuiltinQuery($default_filter)) {
+    continue;
+  }
+
+  $saved = id(new PhabricatorSavedQueryQuery())
+    ->setViewer($viewer)
+    ->withQueryKeys(array($default_filter))
+    ->executeOne();
+  if ($saved) {
+    continue;
+  }
+
+  $properties = $project->getProperties();
+  unset($properties['workboard.filter.default']);
+
+  queryfx(
+    $conn,
+    'UPDATE %T SET properties = %s WHERE id = %d',
+    $table->getTableName(),
+    phutil_json_encode($properties),
+    $project->getID());
+
+  echo tsprintf(
+    "%s\n",
+    pht(
+      'Project ("%s") had an invalid query saved as a default workboard '.
+      'query. The query has been reset. See T13208.',
+      $project->getDisplayName()));
+}
diff --git a/src/applications/project/controller/PhabricatorProjectBoardViewController.php b/src/applications/project/controller/PhabricatorProjectBoardViewController.php
index bb048f22ea..15e0c5d075 100644
--- a/src/applications/project/controller/PhabricatorProjectBoardViewController.php
+++ b/src/applications/project/controller/PhabricatorProjectBoardViewController.php
@@ -1,1372 +1,1372 @@
 <?php
 
 final class PhabricatorProjectBoardViewController
   extends PhabricatorProjectBoardController {
 
   const BATCH_EDIT_ALL = 'all';
 
   private $id;
   private $slug;
   private $queryKey;
   private $sortKey;
   private $showHidden;
 
   public function shouldAllowPublic() {
     return true;
   }
 
   public function handleRequest(AphrontRequest $request) {
     $viewer = $request->getUser();
 
     $response = $this->loadProject();
     if ($response) {
       return $response;
     }
 
     $project = $this->getProject();
 
     $this->readRequestState();
 
     $board_uri = $this->getApplicationURI('board/'.$project->getID().'/');
 
     $search_engine = id(new ManiphestTaskSearchEngine())
       ->setViewer($viewer)
       ->setBaseURI($board_uri)
       ->setIsBoardView(true);
 
     if ($request->isFormPost()
       && !$request->getBool('initialize')
       && !$request->getStr('move')
       && !$request->getStr('queryColumnID')) {
       $saved = $search_engine->buildSavedQueryFromRequest($request);
       $search_engine->saveQuery($saved);
       $filter_form = id(new AphrontFormView())
         ->setUser($viewer);
       $search_engine->buildSearchForm($filter_form, $saved);
       if ($search_engine->getErrors()) {
         return $this->newDialog()
           ->setWidth(AphrontDialogView::WIDTH_FULL)
           ->setTitle(pht('Advanced Filter'))
           ->appendChild($filter_form->buildLayoutView())
           ->setErrors($search_engine->getErrors())
           ->setSubmitURI($board_uri)
           ->addSubmitButton(pht('Apply Filter'))
           ->addCancelButton($board_uri);
       }
       return id(new AphrontRedirectResponse())->setURI(
         $this->getURIWithState(
           $search_engine->getQueryResultsPageURI($saved->getQueryKey())));
     }
 
     $query_key = $this->getDefaultFilter($project);
 
     $request_query = $request->getStr('filter');
     if (strlen($request_query)) {
       $query_key = $request_query;
     }
 
     $uri_query = $request->getURIData('queryKey');
     if (strlen($uri_query)) {
       $query_key = $uri_query;
     }
 
     $this->queryKey = $query_key;
 
     $custom_query = null;
     if ($search_engine->isBuiltinQuery($query_key)) {
       $saved = $search_engine->buildSavedQueryFromBuiltin($query_key);
     } else {
       $saved = id(new PhabricatorSavedQueryQuery())
         ->setViewer($viewer)
         ->withQueryKeys(array($query_key))
         ->executeOne();
 
       if (!$saved) {
         return new Aphront404Response();
       }
 
       $custom_query = $saved;
     }
 
     if ($request->getURIData('filter')) {
       $filter_form = id(new AphrontFormView())
         ->setUser($viewer);
       $search_engine->buildSearchForm($filter_form, $saved);
 
       return $this->newDialog()
         ->setWidth(AphrontDialogView::WIDTH_FULL)
         ->setTitle(pht('Advanced Filter'))
         ->appendChild($filter_form->buildLayoutView())
         ->setSubmitURI($board_uri)
         ->addSubmitButton(pht('Apply Filter'))
         ->addCancelButton($board_uri);
     }
 
     $task_query = $search_engine->buildQueryFromSavedQuery($saved);
 
     $select_phids = array($project->getPHID());
     if ($project->getHasSubprojects() || $project->getHasMilestones()) {
       $descendants = id(new PhabricatorProjectQuery())
         ->setViewer($viewer)
         ->withAncestorProjectPHIDs($select_phids)
         ->execute();
       foreach ($descendants as $descendant) {
         $select_phids[] = $descendant->getPHID();
       }
     }
 
     $tasks = $task_query
       ->withEdgeLogicPHIDs(
         PhabricatorProjectObjectHasProjectEdgeType::EDGECONST,
         PhabricatorQueryConstraint::OPERATOR_ANCESTOR,
         array($select_phids))
       ->setOrder(ManiphestTaskQuery::ORDER_PRIORITY)
       ->setViewer($viewer)
       ->execute();
     $tasks = mpull($tasks, null, 'getPHID');
 
     $board_phid = $project->getPHID();
 
     // Regardless of display order, pass tasks to the layout engine in ID order
     // so layout is consistent.
     $board_tasks = msort($tasks, 'getID');
 
     $layout_engine = id(new PhabricatorBoardLayoutEngine())
       ->setViewer($viewer)
       ->setBoardPHIDs(array($board_phid))
       ->setObjectPHIDs(array_keys($board_tasks))
       ->setFetchAllBoards(true)
       ->executeLayout();
 
     $columns = $layout_engine->getColumns($board_phid);
     if (!$columns || !$project->getHasWorkboard()) {
       $has_normal_columns = false;
 
       foreach ($columns as $column) {
         if (!$column->getProxyPHID()) {
           $has_normal_columns = true;
           break;
         }
       }
 
       $can_edit = PhabricatorPolicyFilter::hasCapability(
         $viewer,
         $project,
         PhabricatorPolicyCapability::CAN_EDIT);
 
       if (!$has_normal_columns) {
         if (!$can_edit) {
           $content = $this->buildNoAccessContent($project);
         } else {
           $content = $this->buildInitializeContent($project);
         }
       } else {
         if (!$can_edit) {
           $content = $this->buildDisabledContent($project);
         } else {
           $content = $this->buildEnableContent($project);
         }
       }
 
       if ($content instanceof AphrontResponse) {
         return $content;
       }
 
       $nav = $this->getProfileMenu();
       $nav->selectFilter(PhabricatorProject::ITEM_WORKBOARD);
 
       $crumbs = $this->buildApplicationCrumbs();
       $crumbs->addTextCrumb(pht('Workboard'));
 
       return $this->newPage()
         ->setTitle(
           array(
             $project->getDisplayName(),
             pht('Workboard'),
           ))
         ->setNavigation($nav)
         ->setCrumbs($crumbs)
         ->appendChild($content);
     }
 
     // If the user wants to turn a particular column into a query, build an
     // apropriate filter and redirect them to the query results page.
     $query_column_id = $request->getInt('queryColumnID');
     if ($query_column_id) {
       $column_id_map = mpull($columns, null, 'getID');
       $query_column = idx($column_id_map, $query_column_id);
       if (!$query_column) {
         return new Aphront404Response();
       }
 
       // Create a saved query to combine the active filter on the workboard
       // with the column filter. If the user currently has constraints on the
       // board, we want to add a new column or project constraint, not
       // completely replace the constraints.
-      $saved_query = clone $saved;
+      $saved_query = $saved->newCopy();
 
       if ($query_column->getProxyPHID()) {
         $project_phids = $saved_query->getParameter('projectPHIDs');
         if (!$project_phids) {
           $project_phids = array();
         }
         $project_phids[] = $query_column->getProxyPHID();
         $saved_query->setParameter('projectPHIDs', $project_phids);
       } else {
         $saved_query->setParameter(
           'columnPHIDs',
           array($query_column->getPHID()));
       }
 
       $search_engine = id(new ManiphestTaskSearchEngine())
         ->setViewer($viewer);
       $search_engine->saveQuery($saved_query);
 
       $query_key = $saved_query->getQueryKey();
       $query_uri = new PhutilURI("/maniphest/query/{$query_key}/#R");
 
       return id(new AphrontRedirectResponse())
         ->setURI($query_uri);
     }
 
     $task_can_edit_map = id(new PhabricatorPolicyFilter())
       ->setViewer($viewer)
       ->requireCapabilities(array(PhabricatorPolicyCapability::CAN_EDIT))
       ->apply($tasks);
 
     // If this is a batch edit, select the editable tasks in the chosen column
     // and ship the user into the batch editor.
     $batch_edit = $request->getStr('batch');
     if ($batch_edit) {
       if ($batch_edit !== self::BATCH_EDIT_ALL) {
         $column_id_map = mpull($columns, null, 'getID');
         $batch_column = idx($column_id_map, $batch_edit);
         if (!$batch_column) {
           return new Aphront404Response();
         }
 
         $batch_task_phids = $layout_engine->getColumnObjectPHIDs(
           $board_phid,
           $batch_column->getPHID());
 
         foreach ($batch_task_phids as $key => $batch_task_phid) {
           if (empty($task_can_edit_map[$batch_task_phid])) {
             unset($batch_task_phids[$key]);
           }
         }
 
         $batch_tasks = array_select_keys($tasks, $batch_task_phids);
       } else {
         $batch_tasks = $task_can_edit_map;
       }
 
       if (!$batch_tasks) {
         $cancel_uri = $this->getURIWithState($board_uri);
         return $this->newDialog()
           ->setTitle(pht('No Editable Tasks'))
           ->appendParagraph(
             pht(
               'The selected column contains no visible tasks which you '.
               'have permission to edit.'))
           ->addCancelButton($board_uri);
       }
 
       // Create a saved query to hold the working set. This allows us to get
       // around URI length limitations with a long "?ids=..." query string.
       // For details, see T10268.
       $search_engine = id(new ManiphestTaskSearchEngine())
         ->setViewer($viewer);
 
       $saved_query = $search_engine->newSavedQuery();
       $saved_query->setParameter('ids', mpull($batch_tasks, 'getID'));
       $search_engine->saveQuery($saved_query);
 
       $query_key = $saved_query->getQueryKey();
 
       $bulk_uri = new PhutilURI("/maniphest/bulk/query/{$query_key}/");
       $bulk_uri->setQueryParam('board', $this->id);
 
       return id(new AphrontRedirectResponse())
         ->setURI($bulk_uri);
     }
 
     $move_id = $request->getStr('move');
     if (strlen($move_id)) {
       $column_id_map = mpull($columns, null, 'getID');
       $move_column = idx($column_id_map, $move_id);
       if (!$move_column) {
         return new Aphront404Response();
       }
 
       $move_task_phids = $layout_engine->getColumnObjectPHIDs(
         $board_phid,
         $move_column->getPHID());
 
       foreach ($move_task_phids as $key => $move_task_phid) {
         if (empty($task_can_edit_map[$move_task_phid])) {
           unset($move_task_phids[$key]);
         }
       }
 
       $move_tasks = array_select_keys($tasks, $move_task_phids);
       $cancel_uri = $this->getURIWithState($board_uri);
 
       if (!$move_tasks) {
         return $this->newDialog()
           ->setTitle(pht('No Movable Tasks'))
           ->appendParagraph(
             pht(
               'The selected column contains no visible tasks which you '.
               'have permission to move.'))
           ->addCancelButton($cancel_uri);
       }
 
       $move_project_phid = $project->getPHID();
       $move_column_phid = null;
       $move_project = null;
       $move_column = null;
       $columns = null;
       $errors = array();
 
       if ($request->isFormPost()) {
         $move_project_phid = head($request->getArr('moveProjectPHID'));
         if (!$move_project_phid) {
           $move_project_phid = $request->getStr('moveProjectPHID');
         }
 
         if (!$move_project_phid) {
           if ($request->getBool('hasProject')) {
             $errors[] = pht('Choose a project to move tasks to.');
           }
         } else {
           $target_project = id(new PhabricatorProjectQuery())
             ->setViewer($viewer)
             ->withPHIDs(array($move_project_phid))
             ->executeOne();
           if (!$target_project) {
             $errors[] = pht('You must choose a valid project.');
           } else if (!$project->getHasWorkboard()) {
             $errors[] = pht(
               'You must choose a project with a workboard.');
           } else {
             $move_project = $target_project;
           }
         }
 
         if ($move_project) {
           $move_engine = id(new PhabricatorBoardLayoutEngine())
             ->setViewer($viewer)
             ->setBoardPHIDs(array($move_project->getPHID()))
             ->setFetchAllBoards(true)
             ->executeLayout();
 
           $columns = $move_engine->getColumns($move_project->getPHID());
           $columns = mpull($columns, null, 'getPHID');
 
           foreach ($columns as $key => $column) {
             if ($column->isHidden()) {
               unset($columns[$key]);
             }
           }
 
           $move_column_phid = $request->getStr('moveColumnPHID');
           if (!$move_column_phid) {
             if ($request->getBool('hasColumn')) {
               $errors[] = pht('Choose a column to move tasks to.');
             }
           } else {
             if (empty($columns[$move_column_phid])) {
               $errors[] = pht(
                 'Choose a valid column on the target workboard to move '.
                 'tasks to.');
             } else if ($columns[$move_column_phid]->getID() == $move_id) {
               $errors[] = pht(
                 'You can not move tasks from a column to itself.');
             } else {
               $move_column = $columns[$move_column_phid];
             }
           }
         }
       }
 
       if ($move_column && $move_project) {
         foreach ($move_tasks as $move_task) {
           $xactions = array();
 
           // If we're switching projects, get out of the old project first
           // and move to the new project.
           if ($move_project->getID() != $project->getID()) {
             $xactions[] = id(new ManiphestTransaction())
               ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
               ->setMetadataValue(
                 'edge:type',
                 PhabricatorProjectObjectHasProjectEdgeType::EDGECONST)
               ->setNewValue(
                 array(
                   '-' => array(
                     $project->getPHID() => $project->getPHID(),
                   ),
                   '+' => array(
                     $move_project->getPHID() => $move_project->getPHID(),
                   ),
                 ));
           }
 
           $xactions[] = id(new ManiphestTransaction())
             ->setTransactionType(PhabricatorTransactions::TYPE_COLUMNS)
             ->setNewValue(
               array(
                 array(
                   'columnPHID' => $move_column->getPHID(),
                 ),
               ));
 
           $editor = id(new ManiphestTransactionEditor())
             ->setActor($viewer)
             ->setContinueOnMissingFields(true)
             ->setContinueOnNoEffect(true)
             ->setContentSourceFromRequest($request);
 
           $editor->applyTransactions($move_task, $xactions);
         }
 
         return id(new AphrontRedirectResponse())
           ->setURI($cancel_uri);
       }
 
       if ($move_project) {
         $column_form = id(new AphrontFormView())
           ->setViewer($viewer)
           ->appendControl(
             id(new AphrontFormSelectControl())
               ->setName('moveColumnPHID')
               ->setLabel(pht('Move to Column'))
               ->setValue($move_column_phid)
               ->setOptions(mpull($columns, 'getDisplayName', 'getPHID')));
 
         return $this->newDialog()
           ->setTitle(pht('Move Tasks'))
           ->setWidth(AphrontDialogView::WIDTH_FORM)
           ->setErrors($errors)
           ->addHiddenInput('move', $move_id)
           ->addHiddenInput('moveProjectPHID', $move_project->getPHID())
           ->addHiddenInput('hasColumn', true)
           ->addHiddenInput('hasProject', true)
           ->appendParagraph(
             pht(
               'Choose a column on the %s workboard to move tasks to:',
               $viewer->renderHandle($move_project->getPHID())))
           ->appendForm($column_form)
           ->addSubmitButton(pht('Move Tasks'))
           ->addCancelButton($cancel_uri);
       }
 
       if ($move_project_phid) {
         $move_project_phid_value = array($move_project_phid);
       } else {
         $move_project_phid_value = array();
       }
 
       $project_form = id(new AphrontFormView())
         ->setViewer($viewer)
         ->appendControl(
           id(new AphrontFormTokenizerControl())
             ->setName('moveProjectPHID')
             ->setLimit(1)
             ->setLabel(pht('Move to Project'))
             ->setValue($move_project_phid_value)
             ->setDatasource(new PhabricatorProjectDatasource()));
 
       return $this->newDialog()
         ->setTitle(pht('Move Tasks'))
         ->setWidth(AphrontDialogView::WIDTH_FORM)
         ->setErrors($errors)
         ->addHiddenInput('move', $move_id)
         ->addHiddenInput('hasProject', true)
         ->appendForm($project_form)
         ->addSubmitButton(pht('Continue'))
         ->addCancelButton($cancel_uri);
     }
 
 
     $board_id = celerity_generate_unique_node_id();
 
     $board = id(new PHUIWorkboardView())
       ->setUser($viewer)
       ->setID($board_id)
       ->addSigil('jx-workboard')
       ->setMetadata(
         array(
           'boardPHID' => $project->getPHID(),
         ));
 
     $visible_columns = array();
     $column_phids = array();
     $visible_phids = array();
     foreach ($columns as $column) {
       if (!$this->showHidden) {
         if ($column->isHidden()) {
           continue;
         }
       }
 
       $proxy = $column->getProxy();
       if ($proxy && !$proxy->isMilestone()) {
         // TODO: For now, don't show subproject columns because we can't
         // handle tasks with multiple positions yet.
         continue;
       }
 
       $task_phids = $layout_engine->getColumnObjectPHIDs(
         $board_phid,
         $column->getPHID());
 
       $column_tasks = array_select_keys($tasks, $task_phids);
 
       // If we aren't using "natural" order, reorder the column by the original
       // query order.
       if ($this->sortKey != PhabricatorProjectColumn::ORDER_NATURAL) {
         $column_tasks = array_select_keys($column_tasks, array_keys($tasks));
       }
 
       $column_phid = $column->getPHID();
 
       $visible_columns[$column_phid] = $column;
       $column_phids[$column_phid] = $column_tasks;
 
       foreach ($column_tasks as $phid => $task) {
         $visible_phids[$phid] = $phid;
       }
     }
 
     $rendering_engine = id(new PhabricatorBoardRenderingEngine())
       ->setViewer($viewer)
       ->setObjects(array_select_keys($tasks, $visible_phids))
       ->setEditMap($task_can_edit_map)
       ->setExcludedProjectPHIDs($select_phids);
 
     $templates = array();
     $column_maps = array();
     $all_tasks = array();
     foreach ($visible_columns as $column_phid => $column) {
       $column_tasks = $column_phids[$column_phid];
 
       $panel = id(new PHUIWorkpanelView())
         ->setHeader($column->getDisplayName())
         ->setSubHeader($column->getDisplayType())
         ->addSigil('workpanel');
 
       $proxy = $column->getProxy();
       if ($proxy) {
         $proxy_id = $proxy->getID();
         $href = $this->getApplicationURI("view/{$proxy_id}/");
         $panel->setHref($href);
       }
 
       $header_icon = $column->getHeaderIcon();
       if ($header_icon) {
         $panel->setHeaderIcon($header_icon);
       }
 
       $display_class = $column->getDisplayClass();
       if ($display_class) {
         $panel->addClass($display_class);
       }
 
       if ($column->isHidden()) {
         $panel->addClass('project-panel-hidden');
       }
 
       $column_menu = $this->buildColumnMenu($project, $column);
       $panel->addHeaderAction($column_menu);
 
       $count_tag = id(new PHUITagView())
         ->setType(PHUITagView::TYPE_SHADE)
         ->setColor(PHUITagView::COLOR_BLUE)
         ->addSigil('column-points')
         ->setName(
           javelin_tag(
             'span',
             array(
               'sigil' => 'column-points-content',
             ),
             pht('-')))
         ->setStyle('display: none');
 
       $panel->setHeaderTag($count_tag);
 
       $cards = id(new PHUIObjectItemListView())
         ->setUser($viewer)
         ->setFlush(true)
         ->setAllowEmptyList(true)
         ->addSigil('project-column')
         ->setItemClass('phui-workcard')
         ->setMetadata(
           array(
             'columnPHID' => $column->getPHID(),
             'pointLimit' => $column->getPointLimit(),
           ));
 
       foreach ($column_tasks as $task) {
         $object_phid = $task->getPHID();
 
         $card = $rendering_engine->renderCard($object_phid);
         $templates[$object_phid] = hsprintf('%s', $card->getItem());
         $column_maps[$column_phid][] = $object_phid;
 
         $all_tasks[$object_phid] = $task;
       }
 
       $panel->setCards($cards);
       $board->addPanel($panel);
     }
 
     $behavior_config = array(
       'moveURI' => $this->getApplicationURI('move/'.$project->getID().'/'),
       'uploadURI' => '/file/dropupload/',
       'coverURI' => $this->getApplicationURI('cover/'),
       'chunkThreshold' => PhabricatorFileStorageEngine::getChunkThreshold(),
       'pointsEnabled' => ManiphestTaskPoints::getIsEnabled(),
 
       'boardPHID' => $project->getPHID(),
       'order' => $this->sortKey,
       'templateMap' => $templates,
       'columnMaps' => $column_maps,
       'orderMaps' => mpull($all_tasks, 'getWorkboardOrderVectors'),
       'propertyMaps' => mpull($all_tasks, 'getWorkboardProperties'),
 
       'boardID' => $board_id,
       'projectPHID' => $project->getPHID(),
     );
     $this->initBehavior('project-boards', $behavior_config);
 
 
     $sort_menu = $this->buildSortMenu(
       $viewer,
       $project,
       $this->sortKey);
 
     $filter_menu = $this->buildFilterMenu(
       $viewer,
       $project,
       $custom_query,
       $search_engine,
       $query_key);
 
     $manage_menu = $this->buildManageMenu($project, $this->showHidden);
 
     $header_link = phutil_tag(
       'a',
       array(
         'href' => $this->getApplicationURI('profile/'.$project->getID().'/'),
       ),
       $project->getName());
 
     $board_box = id(new PHUIBoxView())
       ->appendChild($board)
       ->addClass('project-board-wrapper');
 
     $nav = $this->getProfileMenu();
 
     $divider = id(new PHUIListItemView())
       ->setType(PHUIListItemView::TYPE_DIVIDER);
     $fullscreen = $this->buildFullscreenMenu();
 
     $crumbs = $this->buildApplicationCrumbs();
     $crumbs->addTextCrumb(pht('Workboard'));
     $crumbs->setBorder(true);
 
     $crumbs->addAction($sort_menu);
     $crumbs->addAction($filter_menu);
     $crumbs->addAction($divider);
     $crumbs->addAction($manage_menu);
     $crumbs->addAction($fullscreen);
 
     $page = $this->newPage()
       ->setTitle(
         array(
           $project->getDisplayName(),
           pht('Workboard'),
         ))
       ->setPageObjectPHIDs(array($project->getPHID()))
       ->setShowFooter(false)
       ->setNavigation($nav)
       ->setCrumbs($crumbs)
       ->addQuicksandConfig(
         array(
           'boardConfig' => $behavior_config,
         ))
       ->appendChild(
         array(
           $board_box,
         ));
 
     $background = $project->getDisplayWorkboardBackgroundColor();
     require_celerity_resource('phui-workboard-color-css');
     if ($background !== null) {
       $background_color_class = "phui-workboard-{$background}";
 
       $page->addClass('phui-workboard-color');
       $page->addClass($background_color_class);
     } else {
       $page->addClass('phui-workboard-no-color');
     }
 
     return $page;
   }
 
   private function readRequestState() {
     $request = $this->getRequest();
     $project = $this->getProject();
 
     $this->showHidden = $request->getBool('hidden');
     $this->id = $project->getID();
 
     $sort_key = $this->getDefaultSort($project);
 
     $request_sort = $request->getStr('order');
     if ($this->isValidSort($request_sort)) {
       $sort_key = $request_sort;
     }
 
     $this->sortKey = $sort_key;
   }
 
   private function getDefaultSort(PhabricatorProject $project) {
     $default_sort = $project->getDefaultWorkboardSort();
 
     if ($this->isValidSort($default_sort)) {
       return $default_sort;
     }
 
     return PhabricatorProjectColumn::DEFAULT_ORDER;
   }
 
   private function getDefaultFilter(PhabricatorProject $project) {
     $default_filter = $project->getDefaultWorkboardFilter();
 
     if (strlen($default_filter)) {
       return $default_filter;
     }
 
     return 'open';
   }
 
   private function isValidSort($sort) {
     switch ($sort) {
       case PhabricatorProjectColumn::ORDER_NATURAL:
       case PhabricatorProjectColumn::ORDER_PRIORITY:
         return true;
     }
 
     return false;
   }
 
   private function buildSortMenu(
     PhabricatorUser $viewer,
     PhabricatorProject $project,
     $sort_key) {
 
     $sort_icon = id(new PHUIIconView())
       ->setIcon('fa-sort-amount-asc bluegrey');
 
     $named = array(
       PhabricatorProjectColumn::ORDER_NATURAL => pht('Natural'),
       PhabricatorProjectColumn::ORDER_PRIORITY => pht('Sort by Priority'),
     );
 
     $base_uri = $this->getURIWithState();
 
     $items = array();
     foreach ($named as $key => $name) {
       $is_selected = ($key == $sort_key);
       if ($is_selected) {
         $active_order = $name;
       }
 
       $item = id(new PhabricatorActionView())
         ->setIcon('fa-sort-amount-asc')
         ->setSelected($is_selected)
         ->setName($name);
 
       $uri = $base_uri->alter('order', $key);
       $item->setHref($uri);
 
       $items[] = $item;
     }
 
     $id = $project->getID();
 
     $save_uri = "default/{$id}/sort/";
     $save_uri = $this->getApplicationURI($save_uri);
     $save_uri = $this->getURIWithState($save_uri, $force = true);
 
     $can_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
       $project,
       PhabricatorPolicyCapability::CAN_EDIT);
 
     $items[] = id(new PhabricatorActionView())
       ->setIcon('fa-floppy-o')
       ->setName(pht('Save as Default'))
       ->setHref($save_uri)
       ->setWorkflow(true)
       ->setDisabled(!$can_edit);
 
     $sort_menu = id(new PhabricatorActionListView())
       ->setUser($viewer);
     foreach ($items as $item) {
       $sort_menu->addAction($item);
     }
 
     $sort_button = id(new PHUIListItemView())
       ->setName($active_order)
       ->setIcon('fa-sort-amount-asc')
       ->setHref('#')
       ->addSigil('boards-dropdown-menu')
       ->setMetadata(
         array(
           'items' => hsprintf('%s', $sort_menu),
         ));
 
     return $sort_button;
   }
 
   private function buildFilterMenu(
     PhabricatorUser $viewer,
     PhabricatorProject $project,
     $custom_query,
     PhabricatorApplicationSearchEngine $engine,
     $query_key) {
 
     $named = array(
       'open' => pht('Open Tasks'),
       'all' => pht('All Tasks'),
     );
 
     if ($viewer->isLoggedIn()) {
       $named['assigned'] = pht('Assigned to Me');
     }
 
     if ($custom_query) {
       $named[$custom_query->getQueryKey()] = pht('Custom Filter');
     }
 
     $items = array();
     foreach ($named as $key => $name) {
       $is_selected = ($key == $query_key);
       if ($is_selected) {
         $active_filter = $name;
       }
 
       $is_custom = false;
       if ($custom_query) {
         $is_custom = ($key == $custom_query->getQueryKey());
       }
 
       $item = id(new PhabricatorActionView())
         ->setIcon('fa-search')
         ->setSelected($is_selected)
         ->setName($name);
 
       if ($is_custom) {
         $uri = $this->getApplicationURI(
           'board/'.$this->id.'/filter/query/'.$key.'/');
         $item->setWorkflow(true);
       } else {
         $uri = $engine->getQueryResultsPageURI($key);
       }
 
       $uri = $this->getURIWithState($uri)
         ->setQueryParam('filter', null);
       $item->setHref($uri);
 
       $items[] = $item;
     }
 
     $id = $project->getID();
 
     $filter_uri = $this->getApplicationURI("board/{$id}/filter/");
     $filter_uri = $this->getURIWithState($filter_uri, $force = true);
 
     $items[] = id(new PhabricatorActionView())
       ->setIcon('fa-cog')
       ->setHref($filter_uri)
       ->setWorkflow(true)
       ->setName(pht('Advanced Filter...'));
 
     $save_uri = "default/{$id}/filter/";
     $save_uri = $this->getApplicationURI($save_uri);
     $save_uri = $this->getURIWithState($save_uri, $force = true);
 
     $can_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
       $project,
       PhabricatorPolicyCapability::CAN_EDIT);
 
     $items[] = id(new PhabricatorActionView())
       ->setIcon('fa-floppy-o')
       ->setName(pht('Save as Default'))
       ->setHref($save_uri)
       ->setWorkflow(true)
       ->setDisabled(!$can_edit);
 
     $filter_menu = id(new PhabricatorActionListView())
         ->setUser($viewer);
     foreach ($items as $item) {
       $filter_menu->addAction($item);
     }
 
     $filter_button = id(new PHUIListItemView())
       ->setName($active_filter)
       ->setIcon('fa-search')
       ->setHref('#')
       ->addSigil('boards-dropdown-menu')
       ->setMetadata(
         array(
           'items' => hsprintf('%s', $filter_menu),
         ));
 
     return $filter_button;
   }
 
   private function buildManageMenu(
     PhabricatorProject $project,
     $show_hidden) {
 
     $request = $this->getRequest();
     $viewer = $request->getUser();
 
     $id = $project->getID();
 
     $manage_uri = $this->getApplicationURI("board/{$id}/manage/");
     $add_uri = $this->getApplicationURI("board/{$id}/edit/");
 
     $can_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
       $project,
       PhabricatorPolicyCapability::CAN_EDIT);
 
     $manage_items = array();
 
     $manage_items[] = id(new PhabricatorActionView())
       ->setIcon('fa-plus')
       ->setName(pht('Add Column'))
       ->setHref($add_uri)
       ->setDisabled(!$can_edit)
       ->setWorkflow(true);
 
     $reorder_uri = $this->getApplicationURI("board/{$id}/reorder/");
     $manage_items[] = id(new PhabricatorActionView())
       ->setIcon('fa-exchange')
       ->setName(pht('Reorder Columns'))
       ->setHref($reorder_uri)
       ->setDisabled(!$can_edit)
       ->setWorkflow(true);
 
     if ($show_hidden) {
       $hidden_uri = $this->getURIWithState()
         ->setQueryParam('hidden', null);
       $hidden_icon = 'fa-eye-slash';
       $hidden_text = pht('Hide Hidden Columns');
     } else {
       $hidden_uri = $this->getURIWithState()
         ->setQueryParam('hidden', 'true');
       $hidden_icon = 'fa-eye';
       $hidden_text = pht('Show Hidden Columns');
     }
 
     $manage_items[] = id(new PhabricatorActionView())
       ->setIcon($hidden_icon)
       ->setName($hidden_text)
       ->setHref($hidden_uri);
 
     $manage_items[] = id(new PhabricatorActionView())
       ->setType(PhabricatorActionView::TYPE_DIVIDER);
 
     $background_uri = $this->getApplicationURI("board/{$id}/background/");
     $manage_items[] = id(new PhabricatorActionView())
       ->setIcon('fa-paint-brush')
       ->setName(pht('Change Background Color'))
       ->setHref($background_uri)
       ->setDisabled(!$can_edit)
       ->setWorkflow(false);
 
     $manage_uri = $this->getApplicationURI("board/{$id}/manage/");
     $manage_items[] = id(new PhabricatorActionView())
       ->setIcon('fa-gear')
       ->setName(pht('Manage Workboard'))
       ->setHref($manage_uri);
 
     $batch_edit_uri = $request->getRequestURI();
     $batch_edit_uri->setQueryParam('batch', self::BATCH_EDIT_ALL);
     $can_batch_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
       PhabricatorApplication::getByClass('PhabricatorManiphestApplication'),
       ManiphestBulkEditCapability::CAPABILITY);
 
     $manage_menu = id(new PhabricatorActionListView())
         ->setUser($viewer);
     foreach ($manage_items as $item) {
       $manage_menu->addAction($item);
     }
 
     $manage_button = id(new PHUIListItemView())
       ->setIcon('fa-cog')
       ->setHref('#')
       ->addSigil('boards-dropdown-menu')
       ->addSigil('has-tooltip')
       ->setMetadata(
         array(
           'tip' => pht('Manage'),
           'align' => 'S',
           'items' => hsprintf('%s', $manage_menu),
         ));
 
     return $manage_button;
   }
 
   private function buildFullscreenMenu() {
 
     $up = id(new PHUIListItemView())
       ->setIcon('fa-arrows-alt')
       ->setHref('#')
       ->addClass('phui-workboard-expand-icon')
       ->addSigil('jx-toggle-class')
       ->addSigil('has-tooltip')
       ->setMetaData(array(
         'tip' => pht('Fullscreen'),
         'map' => array(
           'phabricator-standard-page' => 'phui-workboard-fullscreen',
         ),
       ));
 
     return $up;
   }
 
   private function buildColumnMenu(
     PhabricatorProject $project,
     PhabricatorProjectColumn $column) {
 
     $request = $this->getRequest();
     $viewer = $request->getUser();
 
     $can_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
       $project,
       PhabricatorPolicyCapability::CAN_EDIT);
 
     $column_items = array();
 
     if ($column->getProxyPHID()) {
       $default_phid = $column->getProxyPHID();
     } else {
       $default_phid = $column->getProjectPHID();
     }
 
     $specs = id(new ManiphestEditEngine())
       ->setViewer($viewer)
       ->newCreateActionSpecifications(array());
 
     foreach ($specs as $spec) {
       $column_items[] = id(new PhabricatorActionView())
         ->setIcon($spec['icon'])
         ->setName($spec['name'])
         ->setHref($spec['uri'])
         ->setDisabled($spec['disabled'])
         ->addSigil('column-add-task')
         ->setMetadata(
           array(
             'createURI' => $spec['uri'],
             'columnPHID' => $column->getPHID(),
             'boardPHID' => $project->getPHID(),
             'projectPHID' => $default_phid,
           ));
     }
 
     if (count($specs) > 1) {
       $column_items[] = id(new PhabricatorActionView())
         ->setType(PhabricatorActionView::TYPE_DIVIDER);
     }
 
     $batch_edit_uri = $request->getRequestURI();
     $batch_edit_uri->setQueryParam('batch', $column->getID());
     $can_batch_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
       PhabricatorApplication::getByClass('PhabricatorManiphestApplication'),
       ManiphestBulkEditCapability::CAPABILITY);
 
     $column_items[] = id(new PhabricatorActionView())
       ->setIcon('fa-list-ul')
       ->setName(pht('Bulk Edit Tasks...'))
       ->setHref($batch_edit_uri)
       ->setDisabled(!$can_batch_edit);
 
     $batch_move_uri = $request->getRequestURI();
     $batch_move_uri->setQueryParam('move', $column->getID());
     $column_items[] = id(new PhabricatorActionView())
       ->setIcon('fa-arrow-right')
       ->setName(pht('Move Tasks to Column...'))
       ->setHref($batch_move_uri)
       ->setWorkflow(true);
 
     $query_uri = $request->getRequestURI();
     $query_uri->setQueryParam('queryColumnID', $column->getID());
 
     $column_items[] = id(new PhabricatorActionView())
       ->setName(pht('View as Query'))
       ->setIcon('fa-search')
       ->setHref($query_uri);
 
     $edit_uri = 'board/'.$this->id.'/edit/'.$column->getID().'/';
     $column_items[] = id(new PhabricatorActionView())
       ->setName(pht('Edit Column'))
       ->setIcon('fa-pencil')
       ->setHref($this->getApplicationURI($edit_uri))
       ->setDisabled(!$can_edit)
       ->setWorkflow(true);
 
     $can_hide = ($can_edit && !$column->isDefaultColumn());
     $hide_uri = 'board/'.$this->id.'/hide/'.$column->getID().'/';
     $hide_uri = $this->getApplicationURI($hide_uri);
     $hide_uri = $this->getURIWithState($hide_uri);
 
     if (!$column->isHidden()) {
       $column_items[] = id(new PhabricatorActionView())
         ->setName(pht('Hide Column'))
         ->setIcon('fa-eye-slash')
         ->setHref($hide_uri)
         ->setDisabled(!$can_hide)
         ->setWorkflow(true);
     } else {
       $column_items[] = id(new PhabricatorActionView())
         ->setName(pht('Show Column'))
         ->setIcon('fa-eye')
         ->setHref($hide_uri)
         ->setDisabled(!$can_hide)
         ->setWorkflow(true);
     }
 
     $column_menu = id(new PhabricatorActionListView())
       ->setUser($viewer);
     foreach ($column_items as $item) {
       $column_menu->addAction($item);
     }
 
     $column_button = id(new PHUIIconView())
       ->setIcon('fa-caret-down')
       ->setHref('#')
       ->addSigil('boards-dropdown-menu')
       ->setMetadata(
         array(
           'items' => hsprintf('%s', $column_menu),
         ));
 
     return $column_button;
   }
 
 
   /**
    * Add current state parameters (like order and the visibility of hidden
    * columns) to a URI.
    *
    * This allows actions which toggle or adjust one piece of state to keep
    * the rest of the board state persistent. If no URI is provided, this method
    * starts with the request URI.
    *
    * @param string|null URI to add state parameters to.
    * @param bool True to explicitly include all state.
    * @return PhutilURI URI with state parameters.
    */
   private function getURIWithState($base = null, $force = false) {
     $project = $this->getProject();
 
     if ($base === null) {
       $base = $this->getRequest()->getRequestURI();
     }
 
     $base = new PhutilURI($base);
 
     if ($force || ($this->sortKey != $this->getDefaultSort($project))) {
       $base->setQueryParam('order', $this->sortKey);
     } else {
       $base->setQueryParam('order', null);
     }
 
     if ($force || ($this->queryKey != $this->getDefaultFilter($project))) {
       $base->setQueryParam('filter', $this->queryKey);
     } else {
       $base->setQueryParam('filter', null);
     }
 
     $base->setQueryParam('hidden', $this->showHidden ? 'true' : null);
 
     return $base;
   }
 
   private function buildInitializeContent(PhabricatorProject $project) {
     $request = $this->getRequest();
     $viewer = $this->getViewer();
 
     $type = $request->getStr('initialize-type');
 
     $id = $project->getID();
 
     $profile_uri = $this->getApplicationURI("profile/{$id}/");
     $board_uri = $this->getApplicationURI("board/{$id}/");
     $import_uri = $this->getApplicationURI("board/{$id}/import/");
 
     $set_default = $request->getBool('default');
     if ($set_default) {
       $this
         ->getProfileMenuEngine()
         ->adjustDefault(PhabricatorProject::ITEM_WORKBOARD);
     }
 
     if ($request->isFormPost()) {
       if ($type == 'backlog-only') {
         $column = PhabricatorProjectColumn::initializeNewColumn($viewer)
           ->setSequence(0)
           ->setProperty('isDefault', true)
           ->setProjectPHID($project->getPHID())
           ->save();
 
           $xactions = array();
           $xactions[] = id(new PhabricatorProjectTransaction())
             ->setTransactionType(
                 PhabricatorProjectWorkboardTransaction::TRANSACTIONTYPE)
             ->setNewValue(1);
 
           id(new PhabricatorProjectTransactionEditor())
             ->setActor($viewer)
             ->setContentSourceFromRequest($request)
             ->setContinueOnNoEffect(true)
             ->setContinueOnMissingFields(true)
             ->applyTransactions($project, $xactions);
 
         return id(new AphrontRedirectResponse())
           ->setURI($board_uri);
       } else {
         return id(new AphrontRedirectResponse())
           ->setURI($import_uri);
       }
     }
 
     // TODO: Tailor this UI if the project is already a parent project. We
     // should not offer options for creating a parent project workboard, since
     // they can't have their own columns.
 
     $new_selector = id(new AphrontFormRadioButtonControl())
       ->setLabel(pht('Columns'))
       ->setName('initialize-type')
       ->setValue('backlog-only')
       ->addButton(
         'backlog-only',
         pht('New Empty Board'),
         pht('Create a new board with just a backlog column.'))
       ->addButton(
         'import',
         pht('Import Columns'),
         pht('Import board columns from another project.'));
 
     $default_checkbox = id(new AphrontFormCheckboxControl())
       ->setLabel(pht('Make Default'))
       ->addCheckbox(
         'default',
         1,
         pht('Make the workboard the default view for this project.'),
         true);
 
     $form = id(new AphrontFormView())
       ->setUser($viewer)
       ->addHiddenInput('initialize', 1)
       ->appendRemarkupInstructions(
         pht('The workboard for this project has not been created yet.'))
       ->appendControl($new_selector)
       ->appendControl($default_checkbox)
       ->appendControl(
         id(new AphrontFormSubmitControl())
           ->addCancelButton($profile_uri)
           ->setValue(pht('Create Workboard')));
 
     $box = id(new PHUIObjectBoxView())
       ->setHeaderText(pht('Create Workboard'))
       ->setForm($form);
 
     return $box;
   }
 
   private function buildNoAccessContent(PhabricatorProject $project) {
     $viewer = $this->getViewer();
 
     $id = $project->getID();
 
     $profile_uri = $this->getApplicationURI("profile/{$id}/");
 
     return $this->newDialog()
       ->setTitle(pht('Unable to Create Workboard'))
       ->appendParagraph(
         pht(
           'The workboard for this project has not been created yet, '.
           'but you do not have permission to create it. Only users '.
           'who can edit this project can create a workboard for it.'))
       ->addCancelButton($profile_uri);
   }
 
 
   private function buildEnableContent(PhabricatorProject $project) {
     $request = $this->getRequest();
     $viewer = $this->getViewer();
 
     $id = $project->getID();
     $profile_uri = $this->getApplicationURI("profile/{$id}/");
     $board_uri = $this->getApplicationURI("board/{$id}/");
 
     if ($request->isFormPost()) {
       $xactions = array();
 
       $xactions[] = id(new PhabricatorProjectTransaction())
         ->setTransactionType(
             PhabricatorProjectWorkboardTransaction::TRANSACTIONTYPE)
         ->setNewValue(1);
 
       id(new PhabricatorProjectTransactionEditor())
         ->setActor($viewer)
         ->setContentSourceFromRequest($request)
         ->setContinueOnNoEffect(true)
         ->setContinueOnMissingFields(true)
         ->applyTransactions($project, $xactions);
 
       return id(new AphrontRedirectResponse())
         ->setURI($board_uri);
     }
 
     return $this->newDialog()
       ->setTitle(pht('Workboard Disabled'))
       ->addHiddenInput('initialize', 1)
       ->appendParagraph(
         pht(
           'This workboard has been disabled, but can be restored to its '.
           'former glory.'))
       ->addCancelButton($profile_uri)
       ->addSubmitButton(pht('Enable Workboard'));
   }
 
   private function buildDisabledContent(PhabricatorProject $project) {
     $viewer = $this->getViewer();
 
     $id = $project->getID();
 
     $profile_uri = $this->getApplicationURI("profile/{$id}/");
 
     return $this->newDialog()
       ->setTitle(pht('Workboard Disabled'))
       ->appendParagraph(
         pht(
           'This workboard has been disabled, and you do not have permission '.
           'to enable it. Only users who can edit this project can restore '.
           'the workboard.'))
       ->addCancelButton($profile_uri);
   }
 
 }
diff --git a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
index b808291a52..a89a017e85 100644
--- a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
+++ b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
@@ -1,1599 +1,1607 @@
 <?php
 
 /**
  * Represents an abstract search engine for an application. It supports
  * creating and storing saved queries.
  *
  * @task construct  Constructing Engines
  * @task app        Applications
  * @task builtin    Builtin Queries
  * @task uri        Query URIs
  * @task dates      Date Filters
  * @task order      Result Ordering
  * @task read       Reading Utilities
  * @task exec       Paging and Executing Queries
  * @task render     Rendering Results
  */
 abstract class PhabricatorApplicationSearchEngine extends Phobject {
 
   private $application;
   private $viewer;
   private $errors = array();
   private $request;
   private $context;
   private $controller;
   private $namedQueries;
   private $navigationItems = array();
 
   const CONTEXT_LIST  = 'list';
   const CONTEXT_PANEL = 'panel';
 
   const BUCKET_NONE = 'none';
 
   public function setController(PhabricatorController $controller) {
     $this->controller = $controller;
     return $this;
   }
 
   public function getController() {
     return $this->controller;
   }
 
   public function buildResponse() {
     $controller = $this->getController();
     $request = $controller->getRequest();
 
     $search = id(new PhabricatorApplicationSearchController())
       ->setQueryKey($request->getURIData('queryKey'))
       ->setSearchEngine($this);
 
     return $controller->delegateToController($search);
   }
 
   public function newResultObject() {
     // We may be able to get this automatically if newQuery() is implemented.
     $query = $this->newQuery();
     if ($query) {
       $object = $query->newResultObject();
       if ($object) {
         return $object;
       }
     }
 
     return null;
   }
 
   public function newQuery() {
     return null;
   }
 
   public function setViewer(PhabricatorUser $viewer) {
     $this->viewer = $viewer;
     return $this;
   }
 
   protected function requireViewer() {
     if (!$this->viewer) {
       throw new PhutilInvalidStateException('setViewer');
     }
     return $this->viewer;
   }
 
   public function setContext($context) {
     $this->context = $context;
     return $this;
   }
 
   public function isPanelContext() {
     return ($this->context == self::CONTEXT_PANEL);
   }
 
   public function setNavigationItems(array $navigation_items) {
     assert_instances_of($navigation_items, 'PHUIListItemView');
     $this->navigationItems = $navigation_items;
     return $this;
   }
 
   public function getNavigationItems() {
     return $this->navigationItems;
   }
 
   public function canUseInPanelContext() {
     return true;
   }
 
   public function saveQuery(PhabricatorSavedQuery $query) {
+    if ($query->getID()) {
+      throw new Exception(
+        pht(
+          'Query (with ID "%s") has already been saved. Queries are '.
+          'immutable once saved.',
+          $query->getID()));
+    }
+
     $query->setEngineClassName(get_class($this));
 
     $unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
     try {
       $query->save();
     } catch (AphrontDuplicateKeyQueryException $ex) {
       // Ignore, this is just a repeated search.
     }
     unset($unguarded);
   }
 
   /**
    * Create a saved query object from the request.
    *
    * @param AphrontRequest The search request.
    * @return PhabricatorSavedQuery
    */
   public function buildSavedQueryFromRequest(AphrontRequest $request) {
     $fields = $this->buildSearchFields();
     $viewer = $this->requireViewer();
 
     $saved = new PhabricatorSavedQuery();
     foreach ($fields as $field) {
       $field->setViewer($viewer);
 
       $value = $field->readValueFromRequest($request);
       $saved->setParameter($field->getKey(), $value);
     }
 
     return $saved;
   }
 
   /**
    * Executes the saved query.
    *
    * @param PhabricatorSavedQuery The saved query to operate on.
    * @return PhabricatorQuery The result of the query.
    */
   public function buildQueryFromSavedQuery(PhabricatorSavedQuery $original) {
     $saved = clone $original;
     $this->willUseSavedQuery($saved);
 
     $fields = $this->buildSearchFields();
     $viewer = $this->requireViewer();
 
     $map = array();
     foreach ($fields as $field) {
       $field->setViewer($viewer);
       $field->readValueFromSavedQuery($saved);
       $value = $field->getValueForQuery($field->getValue());
       $map[$field->getKey()] = $value;
     }
 
     $original->attachParameterMap($map);
     $query = $this->buildQueryFromParameters($map);
 
     $object = $this->newResultObject();
     if (!$object) {
       return $query;
     }
 
     $extensions = $this->getEngineExtensions();
     foreach ($extensions as $extension) {
       $extension->applyConstraintsToQuery($object, $query, $saved, $map);
     }
 
     $order = $saved->getParameter('order');
     $builtin = $query->getBuiltinOrderAliasMap();
     if (strlen($order) && isset($builtin[$order])) {
       $query->setOrder($order);
     } else {
       // If the order is invalid or not available, we choose the first
       // builtin order. This isn't always the default order for the query,
       // but is the first value in the "Order" dropdown, and makes the query
       // behavior more consistent with the UI. In queries where the two
       // orders differ, this order is the preferred order for humans.
       $query->setOrder(head_key($builtin));
     }
 
     return $query;
   }
 
   /**
    * Hook for subclasses to adjust saved queries prior to use.
    *
    * If an application changes how queries are saved, it can implement this
    * hook to keep old queries working the way users expect, by reading,
    * adjusting, and overwriting parameters.
    *
    * @param PhabricatorSavedQuery Saved query which will be executed.
    * @return void
    */
   protected function willUseSavedQuery(PhabricatorSavedQuery $saved) {
     return;
   }
 
   protected function buildQueryFromParameters(array $parameters) {
     throw new PhutilMethodNotImplementedException();
   }
 
   /**
    * Builds the search form using the request.
    *
    * @param AphrontFormView       Form to populate.
    * @param PhabricatorSavedQuery The query from which to build the form.
    * @return void
    */
   public function buildSearchForm(
     AphrontFormView $form,
     PhabricatorSavedQuery $saved) {
 
     $saved = clone $saved;
     $this->willUseSavedQuery($saved);
 
     $fields = $this->buildSearchFields();
     $fields = $this->adjustFieldsForDisplay($fields);
     $viewer = $this->requireViewer();
 
     foreach ($fields as $field) {
       $field->setViewer($viewer);
       $field->readValueFromSavedQuery($saved);
     }
 
     foreach ($fields as $field) {
       foreach ($field->getErrors() as $error) {
         $this->addError(last($error));
       }
     }
 
     foreach ($fields as $field) {
       $field->appendToForm($form);
     }
   }
 
   protected function buildSearchFields() {
     $fields = array();
 
     foreach ($this->buildCustomSearchFields() as $field) {
       $fields[] = $field;
     }
 
     $object = $this->newResultObject();
     if ($object) {
       $extensions = $this->getEngineExtensions();
       foreach ($extensions as $extension) {
         $extension_fields = $extension->getSearchFields($object);
         foreach ($extension_fields as $extension_field) {
           $fields[] = $extension_field;
         }
       }
     }
 
     $query = $this->newQuery();
     if ($query && $this->shouldShowOrderField()) {
       $orders = $query->getBuiltinOrders();
       $orders = ipull($orders, 'name');
 
       $fields[] = id(new PhabricatorSearchOrderField())
         ->setLabel(pht('Order By'))
         ->setKey('order')
         ->setOrderAliases($query->getBuiltinOrderAliasMap())
         ->setOptions($orders);
     }
 
     $buckets = $this->newResultBuckets();
     if ($query && $buckets) {
       $bucket_options = array(
         self::BUCKET_NONE => pht('No Bucketing'),
       ) + mpull($buckets, 'getResultBucketName');
 
       $fields[] = id(new PhabricatorSearchSelectField())
         ->setLabel(pht('Bucket'))
         ->setKey('bucket')
         ->setOptions($bucket_options);
     }
 
     $field_map = array();
     foreach ($fields as $field) {
       $key = $field->getKey();
       if (isset($field_map[$key])) {
         throw new Exception(
           pht(
             'Two fields in this SearchEngine use the same key ("%s"), but '.
             'each field must use a unique key.',
             $key));
       }
       $field_map[$key] = $field;
     }
 
     return $field_map;
   }
 
   protected function shouldShowOrderField() {
     return true;
   }
 
   private function adjustFieldsForDisplay(array $field_map) {
     $order = $this->getDefaultFieldOrder();
 
     $head_keys = array();
     $tail_keys = array();
     $seen_tail = false;
     foreach ($order as $order_key) {
       if ($order_key === '...') {
         $seen_tail = true;
         continue;
       }
 
       if (!$seen_tail) {
         $head_keys[] = $order_key;
       } else {
         $tail_keys[] = $order_key;
       }
     }
 
     $head = array_select_keys($field_map, $head_keys);
     $body = array_diff_key($field_map, array_fuse($tail_keys));
     $tail = array_select_keys($field_map, $tail_keys);
 
     $result = $head + $body + $tail;
 
     // Force the fulltext "query" field to the top unconditionally.
     $result = array_select_keys($result, array('query')) + $result;
 
     foreach ($this->getHiddenFields() as $hidden_key) {
       unset($result[$hidden_key]);
     }
 
     return $result;
   }
 
   protected function buildCustomSearchFields() {
     throw new PhutilMethodNotImplementedException();
   }
 
 
   /**
    * Define the default display order for fields by returning a list of
    * field keys.
    *
    * You can use the special key `...` to mean "all unspecified fields go
    * here". This lets you easily put important fields at the top of the form,
    * standard fields in the middle of the form, and less important fields at
    * the bottom.
    *
    * For example, you might return a list like this:
    *
    *   return array(
    *     'authorPHIDs',
    *     'reviewerPHIDs',
    *     '...',
    *     'createdAfter',
    *     'createdBefore',
    *   );
    *
    * Any unspecified fields (including custom fields and fields added
    * automatically by infrastructure) will be put in the middle.
    *
    * @return list<string> Default ordering for field keys.
    */
   protected function getDefaultFieldOrder() {
     return array();
   }
 
   /**
    * Return a list of field keys which should be hidden from the viewer.
    *
     * @return list<string> Fields to hide.
    */
   protected function getHiddenFields() {
     return array();
   }
 
   public function getErrors() {
     return $this->errors;
   }
 
   public function addError($error) {
     $this->errors[] = $error;
     return $this;
   }
 
   /**
    * Return an application URI corresponding to the results page of a query.
    * Normally, this is something like `/application/query/QUERYKEY/`.
    *
    * @param   string  The query key to build a URI for.
    * @return  string  URI where the query can be executed.
    * @task uri
    */
   public function getQueryResultsPageURI($query_key) {
     return $this->getURI('query/'.$query_key.'/');
   }
 
 
   /**
    * Return an application URI for query management. This is used when, e.g.,
    * a query deletion operation is cancelled.
    *
    * @return  string  URI where queries can be managed.
    * @task uri
    */
   public function getQueryManagementURI() {
     return $this->getURI('query/edit/');
   }
 
   public function getQueryBaseURI() {
     return $this->getURI('');
   }
 
   public function getExportURI($query_key) {
     return $this->getURI('query/'.$query_key.'/export/');
   }
 
 
   /**
    * Return the URI to a path within the application. Used to construct default
    * URIs for management and results.
    *
    * @return string URI to path.
    * @task uri
    */
   abstract protected function getURI($path);
 
 
   /**
    * Return a human readable description of the type of objects this query
    * searches for.
    *
    * For example, "Tasks" or "Commits".
    *
    * @return string Human-readable description of what this engine is used to
    *   find.
    */
   abstract public function getResultTypeDescription();
 
 
   public function newSavedQuery() {
     return id(new PhabricatorSavedQuery())
       ->setEngineClassName(get_class($this));
   }
 
   public function addNavigationItems(PHUIListView $menu) {
     $viewer = $this->requireViewer();
 
     $menu->newLabel(pht('Queries'));
 
     $named_queries = $this->loadEnabledNamedQueries();
 
     foreach ($named_queries as $query) {
       $key = $query->getQueryKey();
       $uri = $this->getQueryResultsPageURI($key);
       $menu->newLink($query->getQueryName(), $uri, 'query/'.$key);
     }
 
     if ($viewer->isLoggedIn()) {
       $manage_uri = $this->getQueryManagementURI();
       $menu->newLink(pht('Edit Queries...'), $manage_uri, 'query/edit');
     }
 
     $menu->newLabel(pht('Search'));
     $advanced_uri = $this->getQueryResultsPageURI('advanced');
     $menu->newLink(pht('Advanced Search'), $advanced_uri, 'query/advanced');
 
     foreach ($this->navigationItems as $extra_item) {
       $menu->addMenuItem($extra_item);
     }
 
     return $this;
   }
 
   public function loadAllNamedQueries() {
     $viewer = $this->requireViewer();
     $builtin = $this->getBuiltinQueries();
 
     if ($this->namedQueries === null) {
       $named_queries = id(new PhabricatorNamedQueryQuery())
         ->setViewer($viewer)
         ->withEngineClassNames(array(get_class($this)))
         ->withUserPHIDs(
           array(
             $viewer->getPHID(),
             PhabricatorNamedQuery::SCOPE_GLOBAL,
           ))
         ->execute();
       $named_queries = mpull($named_queries, null, 'getQueryKey');
 
       $builtin = mpull($builtin, null, 'getQueryKey');
 
       foreach ($named_queries as $key => $named_query) {
         if ($named_query->getIsBuiltin()) {
           if (isset($builtin[$key])) {
             $named_queries[$key]->setQueryName($builtin[$key]->getQueryName());
             unset($builtin[$key]);
           } else {
             unset($named_queries[$key]);
           }
         }
 
         unset($builtin[$key]);
       }
 
       $named_queries = msortv($named_queries, 'getNamedQuerySortVector');
       $this->namedQueries = $named_queries;
     }
 
     return $this->namedQueries + $builtin;
   }
 
   public function loadEnabledNamedQueries() {
     $named_queries = $this->loadAllNamedQueries();
     foreach ($named_queries as $key => $named_query) {
       if ($named_query->getIsBuiltin() && $named_query->getIsDisabled()) {
         unset($named_queries[$key]);
       }
     }
     return $named_queries;
   }
 
   public function getDefaultQueryKey() {
     $viewer = $this->requireViewer();
 
     $configs = id(new PhabricatorNamedQueryConfigQuery())
       ->setViewer($viewer)
       ->withEngineClassNames(array(get_class($this)))
       ->withScopePHIDs(
         array(
           $viewer->getPHID(),
           PhabricatorNamedQueryConfig::SCOPE_GLOBAL,
         ))
       ->execute();
     $configs = msortv($configs, 'getStrengthSortVector');
 
     $key_pinned = PhabricatorNamedQueryConfig::PROPERTY_PINNED;
     $map = $this->loadEnabledNamedQueries();
     foreach ($configs as $config) {
       $pinned = $config->getConfigProperty($key_pinned);
       if (!isset($map[$pinned])) {
         continue;
       }
 
       return $pinned;
     }
 
     return head_key($map);
   }
 
   protected function setQueryProjects(
     PhabricatorCursorPagedPolicyAwareQuery $query,
     PhabricatorSavedQuery $saved) {
 
     $datasource = id(new PhabricatorProjectLogicalDatasource())
       ->setViewer($this->requireViewer());
 
     $projects = $saved->getParameter('projects', array());
     $constraints = $datasource->evaluateTokens($projects);
 
     if ($constraints) {
       $query->withEdgeLogicConstraints(
         PhabricatorProjectObjectHasProjectEdgeType::EDGECONST,
         $constraints);
     }
 
     return $this;
   }
 
 
 /* -(  Applications  )------------------------------------------------------- */
 
 
   protected function getApplicationURI($path = '') {
     return $this->getApplication()->getApplicationURI($path);
   }
 
   protected function getApplication() {
     if (!$this->application) {
       $class = $this->getApplicationClassName();
 
       $this->application = id(new PhabricatorApplicationQuery())
         ->setViewer($this->requireViewer())
         ->withClasses(array($class))
         ->withInstalled(true)
         ->executeOne();
 
       if (!$this->application) {
         throw new Exception(
           pht(
             'Application "%s" is not installed!',
             $class));
       }
     }
 
     return $this->application;
   }
 
   abstract public function getApplicationClassName();
 
 
 /* -(  Constructing Engines  )----------------------------------------------- */
 
 
   /**
    * Load all available application search engines.
    *
    * @return list<PhabricatorApplicationSearchEngine> All available engines.
    * @task construct
    */
   public static function getAllEngines() {
     return id(new PhutilClassMapQuery())
       ->setAncestorClass(__CLASS__)
       ->execute();
   }
 
 
   /**
    * Get an engine by class name, if it exists.
    *
    * @return PhabricatorApplicationSearchEngine|null Engine, or null if it does
    *   not exist.
    * @task construct
    */
   public static function getEngineByClassName($class_name) {
     return idx(self::getAllEngines(), $class_name);
   }
 
 
 /* -(  Builtin Queries  )---------------------------------------------------- */
 
 
   /**
    * @task builtin
    */
   public function getBuiltinQueries() {
     $names = $this->getBuiltinQueryNames();
 
     $queries = array();
     $sequence = 0;
     foreach ($names as $key => $name) {
       $queries[$key] = id(new PhabricatorNamedQuery())
         ->setUserPHID(PhabricatorNamedQuery::SCOPE_GLOBAL)
         ->setEngineClassName(get_class($this))
         ->setQueryName($name)
         ->setQueryKey($key)
         ->setSequence((1 << 24) + $sequence++)
         ->setIsBuiltin(true);
     }
 
     return $queries;
   }
 
 
   /**
    * @task builtin
    */
   public function getBuiltinQuery($query_key) {
     if (!$this->isBuiltinQuery($query_key)) {
       throw new Exception(pht("'%s' is not a builtin!", $query_key));
     }
     return idx($this->getBuiltinQueries(), $query_key);
   }
 
 
   /**
    * @task builtin
    */
   protected function getBuiltinQueryNames() {
     return array();
   }
 
 
   /**
    * @task builtin
    */
   public function isBuiltinQuery($query_key) {
     $builtins = $this->getBuiltinQueries();
     return isset($builtins[$query_key]);
   }
 
 
   /**
    * @task builtin
    */
   public function buildSavedQueryFromBuiltin($query_key) {
     throw new Exception(pht("Builtin '%s' is not supported!", $query_key));
   }
 
 
 /* -(  Reading Utilities )--------------------------------------------------- */
 
 
   /**
    * Read a list of user PHIDs from a request in a flexible way. This method
    * supports either of these forms:
    *
    *   users[]=alincoln&users[]=htaft
    *   users=alincoln,htaft
    *
    * Additionally, users can be specified either by PHID or by name.
    *
    * The main goal of this flexibility is to allow external programs to generate
    * links to pages (like "alincoln's open revisions") without needing to make
    * API calls.
    *
    * @param AphrontRequest  Request to read user PHIDs from.
    * @param string          Key to read in the request.
    * @param list<const>     Other permitted PHID types.
    * @return list<phid>     List of user PHIDs and selector functions.
    * @task read
    */
   protected function readUsersFromRequest(
     AphrontRequest $request,
     $key,
     array $allow_types = array()) {
 
     $list = $this->readListFromRequest($request, $key);
 
     $phids = array();
     $names = array();
     $allow_types = array_fuse($allow_types);
     $user_type = PhabricatorPeopleUserPHIDType::TYPECONST;
     foreach ($list as $item) {
       $type = phid_get_type($item);
       if ($type == $user_type) {
         $phids[] = $item;
       } else if (isset($allow_types[$type])) {
         $phids[] = $item;
       } else {
         if (PhabricatorTypeaheadDatasource::isFunctionToken($item)) {
           // If this is a function, pass it through unchanged; we'll evaluate
           // it later.
           $phids[] = $item;
         } else {
           $names[] = $item;
         }
       }
     }
 
     if ($names) {
       $users = id(new PhabricatorPeopleQuery())
         ->setViewer($this->requireViewer())
         ->withUsernames($names)
         ->execute();
       foreach ($users as $user) {
         $phids[] = $user->getPHID();
       }
       $phids = array_unique($phids);
     }
 
     return $phids;
   }
 
 
   /**
    * Read a list of subscribers from a request in a flexible way.
    *
    * @param AphrontRequest  Request to read PHIDs from.
    * @param string          Key to read in the request.
    * @return list<phid>     List of object PHIDs.
    * @task read
    */
   protected function readSubscribersFromRequest(
     AphrontRequest $request,
     $key) {
     return $this->readUsersFromRequest(
       $request,
       $key,
       array(
         PhabricatorProjectProjectPHIDType::TYPECONST,
       ));
   }
 
 
   /**
    * Read a list of generic PHIDs from a request in a flexible way. Like
    * @{method:readUsersFromRequest}, this method supports either array or
    * comma-delimited forms. Objects can be specified either by PHID or by
    * object name.
    *
    * @param AphrontRequest  Request to read PHIDs from.
    * @param string          Key to read in the request.
    * @param list<const>     Optional, list of permitted PHID types.
    * @return list<phid>     List of object PHIDs.
    *
    * @task read
    */
   protected function readPHIDsFromRequest(
     AphrontRequest $request,
     $key,
     array $allow_types = array()) {
 
     $list = $this->readListFromRequest($request, $key);
 
     $objects = id(new PhabricatorObjectQuery())
       ->setViewer($this->requireViewer())
       ->withNames($list)
       ->execute();
     $list = mpull($objects, 'getPHID');
 
     if (!$list) {
       return array();
     }
 
     // If only certain PHID types are allowed, filter out all the others.
     if ($allow_types) {
       $allow_types = array_fuse($allow_types);
       foreach ($list as $key => $phid) {
         if (empty($allow_types[phid_get_type($phid)])) {
           unset($list[$key]);
         }
       }
     }
 
     return $list;
   }
 
 
   /**
    * Read a list of items from the request, in either array format or string
    * format:
    *
    *   list[]=item1&list[]=item2
    *   list=item1,item2
    *
    * This provides flexibility when constructing URIs, especially from external
    * sources.
    *
    * @param AphrontRequest  Request to read strings from.
    * @param string          Key to read in the request.
    * @return list<string>   List of values.
    */
   protected function readListFromRequest(
     AphrontRequest $request,
     $key) {
     $list = $request->getArr($key, null);
     if ($list === null) {
       $list = $request->getStrList($key);
     }
 
     if (!$list) {
       return array();
     }
 
     return $list;
   }
 
   protected function readBoolFromRequest(
     AphrontRequest $request,
     $key) {
     if (!strlen($request->getStr($key))) {
       return null;
     }
     return $request->getBool($key);
   }
 
 
   protected function getBoolFromQuery(PhabricatorSavedQuery $query, $key) {
     $value = $query->getParameter($key);
     if ($value === null) {
       return $value;
     }
     return $value ? 'true' : 'false';
   }
 
 
 /* -(  Dates  )-------------------------------------------------------------- */
 
 
   /**
    * @task dates
    */
   protected function parseDateTime($date_time) {
     if (!strlen($date_time)) {
       return null;
     }
 
     return PhabricatorTime::parseLocalTime($date_time, $this->requireViewer());
   }
 
 
   /**
    * @task dates
    */
   protected function buildDateRange(
     AphrontFormView $form,
     PhabricatorSavedQuery $saved_query,
     $start_key,
     $start_name,
     $end_key,
     $end_name) {
 
     $start_str = $saved_query->getParameter($start_key);
     $start = null;
     if (strlen($start_str)) {
       $start = $this->parseDateTime($start_str);
       if (!$start) {
         $this->addError(
           pht(
             '"%s" date can not be parsed.',
             $start_name));
       }
     }
 
 
     $end_str = $saved_query->getParameter($end_key);
     $end = null;
     if (strlen($end_str)) {
       $end = $this->parseDateTime($end_str);
       if (!$end) {
         $this->addError(
           pht(
             '"%s" date can not be parsed.',
             $end_name));
       }
     }
 
     if ($start && $end && ($start >= $end)) {
       $this->addError(
         pht(
           '"%s" must be a date before "%s".',
           $start_name,
           $end_name));
     }
 
     $form
       ->appendChild(
         id(new PHUIFormFreeformDateControl())
           ->setName($start_key)
           ->setLabel($start_name)
           ->setValue($start_str))
       ->appendChild(
         id(new AphrontFormTextControl())
           ->setName($end_key)
           ->setLabel($end_name)
           ->setValue($end_str));
   }
 
 
 /* -(  Paging and Executing Queries  )--------------------------------------- */
 
 
   protected function newResultBuckets() {
     return array();
   }
 
   public function getResultBucket(PhabricatorSavedQuery $saved) {
     $key = $saved->getParameter('bucket');
     if ($key == self::BUCKET_NONE) {
       return null;
     }
 
     $buckets = $this->newResultBuckets();
     return idx($buckets, $key);
   }
 
 
   public function getPageSize(PhabricatorSavedQuery $saved) {
     $bucket = $this->getResultBucket($saved);
 
     $limit = (int)$saved->getParameter('limit');
 
     if ($limit > 0) {
       if ($bucket) {
         $bucket->setPageSize($limit);
       }
       return $limit;
     }
 
     if ($bucket) {
       return $bucket->getPageSize();
     }
 
     return 100;
   }
 
 
   public function shouldUseOffsetPaging() {
     return false;
   }
 
 
   public function newPagerForSavedQuery(PhabricatorSavedQuery $saved) {
     if ($this->shouldUseOffsetPaging()) {
       $pager = new PHUIPagerView();
     } else {
       $pager = new AphrontCursorPagerView();
     }
 
     $page_size = $this->getPageSize($saved);
     if (is_finite($page_size)) {
       $pager->setPageSize($page_size);
     } else {
       // Consider an INF pagesize to mean a large finite pagesize.
 
       // TODO: It would be nice to handle this more gracefully, but math
       // with INF seems to vary across PHP versions, systems, and runtimes.
       $pager->setPageSize(0xFFFF);
     }
 
     return $pager;
   }
 
 
   public function executeQuery(
     PhabricatorPolicyAwareQuery $query,
     AphrontView $pager) {
 
     $query->setViewer($this->requireViewer());
 
     if ($this->shouldUseOffsetPaging()) {
       $objects = $query->executeWithOffsetPager($pager);
     } else {
       $objects = $query->executeWithCursorPager($pager);
     }
 
     $this->didExecuteQuery($query);
 
     return $objects;
   }
 
   protected function didExecuteQuery(PhabricatorPolicyAwareQuery $query) {
     return;
   }
 
 
 /* -(  Rendering  )---------------------------------------------------------- */
 
 
   public function setRequest(AphrontRequest $request) {
     $this->request = $request;
     return $this;
   }
 
   public function getRequest() {
     return $this->request;
   }
 
   public function renderResults(
     array $objects,
     PhabricatorSavedQuery $query) {
 
     $phids = $this->getRequiredHandlePHIDsForResultList($objects, $query);
 
     if ($phids) {
       $handles = id(new PhabricatorHandleQuery())
         ->setViewer($this->requireViewer())
         ->witHPHIDs($phids)
         ->execute();
     } else {
       $handles = array();
     }
 
     return $this->renderResultList($objects, $query, $handles);
   }
 
   protected function getRequiredHandlePHIDsForResultList(
     array $objects,
     PhabricatorSavedQuery $query) {
     return array();
   }
 
   abstract protected function renderResultList(
     array $objects,
     PhabricatorSavedQuery $query,
     array $handles);
 
 
 /* -(  Application Search  )------------------------------------------------- */
 
 
   public function getSearchFieldsForConduit() {
     $standard_fields = $this->buildSearchFields();
 
     $fields = array();
     foreach ($standard_fields as $field_key => $field) {
       $conduit_key = $field->getConduitKey();
 
       if (isset($fields[$conduit_key])) {
         $other = $fields[$conduit_key];
         $other_key = $other->getKey();
 
         throw new Exception(
           pht(
             'SearchFields "%s" (of class "%s") and "%s" (of class "%s") both '.
             'define the same Conduit key ("%s"). Keys must be unique.',
             $field_key,
             get_class($field),
             $other_key,
             get_class($other),
             $conduit_key));
       }
 
       $fields[$conduit_key] = $field;
     }
 
     // These are handled separately for Conduit, so don't show them as
     // supported.
     unset($fields['order']);
     unset($fields['limit']);
 
     $viewer = $this->requireViewer();
     foreach ($fields as $key => $field) {
       $field->setViewer($viewer);
     }
 
     return $fields;
   }
 
   public function buildConduitResponse(
     ConduitAPIRequest $request,
     ConduitAPIMethod $method) {
     $viewer = $this->requireViewer();
 
     $query_key = $request->getValue('queryKey');
     if (!strlen($query_key)) {
       $saved_query = new PhabricatorSavedQuery();
     } else if ($this->isBuiltinQuery($query_key)) {
       $saved_query = $this->buildSavedQueryFromBuiltin($query_key);
     } else {
       $saved_query = id(new PhabricatorSavedQueryQuery())
         ->setViewer($viewer)
         ->withQueryKeys(array($query_key))
         ->executeOne();
       if (!$saved_query) {
         throw new Exception(
           pht(
             'Query key "%s" does not correspond to a valid query.',
             $query_key));
       }
     }
 
     $constraints = $request->getValue('constraints', array());
 
     $fields = $this->getSearchFieldsForConduit();
 
     foreach ($fields as $key => $field) {
       if (!$field->getConduitParameterType()) {
         unset($fields[$key]);
       }
     }
 
     $valid_constraints = array();
     foreach ($fields as $field) {
       foreach ($field->getValidConstraintKeys() as $key) {
         $valid_constraints[$key] = true;
       }
     }
 
     foreach ($constraints as $key => $constraint) {
       if (empty($valid_constraints[$key])) {
         throw new Exception(
           pht(
             'Constraint "%s" is not a valid constraint for this query.',
             $key));
       }
     }
 
     foreach ($fields as $field) {
       if (!$field->getValueExistsInConduitRequest($constraints)) {
         continue;
       }
 
       $value = $field->readValueFromConduitRequest(
         $constraints,
         $request->getIsStrictlyTyped());
       $saved_query->setParameter($field->getKey(), $value);
     }
 
     // NOTE: Currently, when running an ad-hoc query we never persist it into
     // a saved query. We might want to add an option to do this in the future
     // (for example, to enable a CLI-to-Web workflow where user can view more
     // details about results by following a link), but have no use cases for
     // it today. If we do identify a use case, we could save the query here.
 
     $query = $this->buildQueryFromSavedQuery($saved_query);
     $pager = $this->newPagerForSavedQuery($saved_query);
 
     $attachments = $this->getConduitSearchAttachments();
 
     // TODO: Validate this better.
     $attachment_specs = $request->getValue('attachments', array());
     $attachments = array_select_keys(
       $attachments,
       array_keys($attachment_specs));
 
     foreach ($attachments as $key => $attachment) {
       $attachment->setViewer($viewer);
     }
 
     foreach ($attachments as $key => $attachment) {
       $attachment->willLoadAttachmentData($query, $attachment_specs[$key]);
     }
 
     $this->setQueryOrderForConduit($query, $request);
     $this->setPagerLimitForConduit($pager, $request);
     $this->setPagerOffsetsForConduit($pager, $request);
 
     $objects = $this->executeQuery($query, $pager);
 
     $data = array();
     if ($objects) {
       $field_extensions = $this->getConduitFieldExtensions();
 
       $extension_data = array();
       foreach ($field_extensions as $key => $extension) {
         $extension_data[$key] = $extension->loadExtensionConduitData($objects);
       }
 
       $attachment_data = array();
       foreach ($attachments as $key => $attachment) {
         $attachment_data[$key] = $attachment->loadAttachmentData(
           $objects,
           $attachment_specs[$key]);
       }
 
       foreach ($objects as $object) {
         $field_map = $this->getObjectWireFieldsForConduit(
           $object,
           $field_extensions,
           $extension_data);
 
         $attachment_map = array();
         foreach ($attachments as $key => $attachment) {
           $attachment_map[$key] = $attachment->getAttachmentForObject(
             $object,
             $attachment_data[$key],
             $attachment_specs[$key]);
         }
 
         // If this is empty, we still want to emit a JSON object, not a
         // JSON list.
         if (!$attachment_map) {
           $attachment_map = (object)$attachment_map;
         }
 
         $id = (int)$object->getID();
         $phid = $object->getPHID();
 
         $data[] = array(
           'id' => $id,
           'type' => phid_get_type($phid),
           'phid' => $phid,
           'fields' => $field_map,
           'attachments' => $attachment_map,
         );
       }
     }
 
     return array(
       'data' => $data,
       'maps' => $method->getQueryMaps($query),
       'query' => array(
         // This may be `null` if we have not saved the query.
         'queryKey' => $saved_query->getQueryKey(),
       ),
       'cursor' => array(
         'limit' => $pager->getPageSize(),
         'after' => $pager->getNextPageID(),
         'before' => $pager->getPrevPageID(),
         'order' => $request->getValue('order'),
       ),
     );
   }
 
   public function getAllConduitFieldSpecifications() {
     $extensions = $this->getConduitFieldExtensions();
     $object = $this->newQuery()->newResultObject();
 
     $map = array();
     foreach ($extensions as $extension) {
       $specifications = $extension->getFieldSpecificationsForConduit($object);
       foreach ($specifications as $specification) {
         $key = $specification->getKey();
         if (isset($map[$key])) {
           throw new Exception(
             pht(
               'Two field specifications share the same key ("%s"). Each '.
               'specification must have a unique key.',
               $key));
         }
         $map[$key] = $specification;
       }
     }
 
     return $map;
   }
 
   private function getEngineExtensions() {
     $extensions = PhabricatorSearchEngineExtension::getAllEnabledExtensions();
 
     foreach ($extensions as $key => $extension) {
       $extension
         ->setViewer($this->requireViewer())
         ->setSearchEngine($this);
     }
 
     $object = $this->newResultObject();
     foreach ($extensions as $key => $extension) {
       if (!$extension->supportsObject($object)) {
         unset($extensions[$key]);
       }
     }
 
     return $extensions;
   }
 
 
   private function getConduitFieldExtensions() {
     $extensions = $this->getEngineExtensions();
     $object = $this->newResultObject();
 
     foreach ($extensions as $key => $extension) {
       if (!$extension->getFieldSpecificationsForConduit($object)) {
         unset($extensions[$key]);
       }
     }
 
     return $extensions;
   }
 
   private function setQueryOrderForConduit($query, ConduitAPIRequest $request) {
     $order = $request->getValue('order');
     if ($order === null) {
       return;
     }
 
     if (is_scalar($order)) {
       $query->setOrder($order);
     } else {
       $query->setOrderVector($order);
     }
   }
 
   private function setPagerLimitForConduit($pager, ConduitAPIRequest $request) {
     $limit = $request->getValue('limit');
 
     // If there's no limit specified and the query uses a weird huge page
     // size, just leave it at the default gigantic page size. Otherwise,
     // make sure it's between 1 and 100, inclusive.
 
     if ($limit === null) {
       if ($pager->getPageSize() >= 0xFFFF) {
         return;
       } else {
         $limit = 100;
       }
     }
 
     if ($limit > 100) {
       throw new Exception(
         pht(
           'Maximum page size for Conduit API method calls is 100, but '.
           'this call specified %s.',
           $limit));
     }
 
     if ($limit < 1) {
       throw new Exception(
         pht(
           'Minimum page size for API searches is 1, but this call '.
           'specified %s.',
           $limit));
     }
 
     $pager->setPageSize($limit);
   }
 
   private function setPagerOffsetsForConduit(
     $pager,
     ConduitAPIRequest $request) {
     $before_id = $request->getValue('before');
     if ($before_id !== null) {
       $pager->setBeforeID($before_id);
     }
 
     $after_id = $request->getValue('after');
     if ($after_id !== null) {
       $pager->setAfterID($after_id);
     }
   }
 
   protected function getObjectWireFieldsForConduit(
     $object,
     array $field_extensions,
     array $extension_data) {
 
     $fields = array();
     foreach ($field_extensions as $key => $extension) {
       $data = idx($extension_data, $key, array());
       $fields += $extension->getFieldValuesForConduit($object, $data);
     }
 
     return $fields;
   }
 
   public function getConduitSearchAttachments() {
     $extensions = $this->getEngineExtensions();
     $object = $this->newResultObject();
 
     $attachments = array();
     foreach ($extensions as $extension) {
       $extension_attachments = $extension->getSearchAttachments($object);
       foreach ($extension_attachments as $attachment) {
         $attachment_key = $attachment->getAttachmentKey();
         if (isset($attachments[$attachment_key])) {
           $other = $attachments[$attachment_key];
           throw new Exception(
             pht(
               'Two search engine attachments (of classes "%s" and "%s") '.
               'specify the same attachment key ("%s"); keys must be unique.',
               get_class($attachment),
               get_class($other),
               $attachment_key));
         }
         $attachments[$attachment_key] = $attachment;
       }
     }
 
     return $attachments;
   }
 
   final public function renderNewUserView() {
     $body = $this->getNewUserBody();
 
     if (!$body) {
       return null;
     }
 
     return $body;
   }
 
   protected function getNewUserHeader() {
     return null;
   }
 
   protected function getNewUserBody() {
     return null;
   }
 
   public function newUseResultsActions(PhabricatorSavedQuery $saved) {
     return array();
   }
 
 
 /* -(  Export  )------------------------------------------------------------- */
 
 
   public function canExport() {
     $fields = $this->newExportFields();
     return (bool)$fields;
   }
 
   final public function newExportFieldList() {
     $object = $this->newResultObject();
 
     $builtin_fields = array(
       id(new PhabricatorIDExportField())
         ->setKey('id')
         ->setLabel(pht('ID')),
     );
 
     if ($object->getConfigOption(LiskDAO::CONFIG_AUX_PHID)) {
       $builtin_fields[] = id(new PhabricatorPHIDExportField())
         ->setKey('phid')
         ->setLabel(pht('PHID'));
     }
 
     $fields = mpull($builtin_fields, null, 'getKey');
 
     $export_fields = $this->newExportFields();
     foreach ($export_fields as $export_field) {
       $key = $export_field->getKey();
 
       if (isset($fields[$key])) {
         throw new Exception(
           pht(
             'Search engine ("%s") defines an export field with a key ("%s") '.
             'that collides with another field. Each field must have a '.
             'unique key.',
             get_class($this),
             $key));
       }
 
       $fields[$key] = $export_field;
     }
 
     $extensions = $this->newExportExtensions();
     foreach ($extensions as $extension) {
       $extension_fields = $extension->newExportFields();
       foreach ($extension_fields as $extension_field) {
         $key = $extension_field->getKey();
 
         if (isset($fields[$key])) {
           throw new Exception(
             pht(
               'Export engine extension ("%s") defines an export field with '.
               'a key ("%s") that collides with another field. Each field '.
               'must have a unique key.',
               get_class($extension_field),
               $key));
         }
 
         $fields[$key] = $extension_field;
       }
     }
 
     return $fields;
   }
 
   final public function newExport(array $objects) {
     $object = $this->newResultObject();
     $has_phid = $object->getConfigOption(LiskDAO::CONFIG_AUX_PHID);
 
     $objects = array_values($objects);
     $n = count($objects);
 
     $maps = array();
     foreach ($objects as $object) {
       $map = array(
         'id' => $object->getID(),
       );
 
       if ($has_phid) {
         $map['phid'] = $object->getPHID();
       }
 
       $maps[] = $map;
     }
 
     $export_data = $this->newExportData($objects);
     $export_data = array_values($export_data);
     if (count($export_data) !== count($objects)) {
       throw new Exception(
         pht(
           'Search engine ("%s") exported the wrong number of objects, '.
           'expected %s but got %s.',
           get_class($this),
           phutil_count($objects),
           phutil_count($export_data)));
     }
 
     for ($ii = 0; $ii < $n; $ii++) {
       $maps[$ii] += $export_data[$ii];
     }
 
     $extensions = $this->newExportExtensions();
     foreach ($extensions as $extension) {
       $extension_data = $extension->newExportData($objects);
       $extension_data = array_values($extension_data);
       if (count($export_data) !== count($objects)) {
         throw new Exception(
           pht(
             'Export engine extension ("%s") exported the wrong number of '.
             'objects, expected %s but got %s.',
             get_class($extension),
             phutil_count($objects),
             phutil_count($export_data)));
       }
 
       for ($ii = 0; $ii < $n; $ii++) {
         $maps[$ii] += $extension_data[$ii];
       }
     }
 
     return $maps;
   }
 
   protected function newExportFields() {
     return array();
   }
 
   protected function newExportData(array $objects) {
     throw new PhutilMethodNotImplementedException();
   }
 
   private function newExportExtensions() {
     $object = $this->newResultObject();
     $viewer = $this->requireViewer();
 
     $extensions = PhabricatorExportEngineExtension::getAllExtensions();
 
     $supported = array();
     foreach ($extensions as $extension) {
       $extension = clone $extension;
       $extension->setViewer($viewer);
 
       if ($extension->supportsObject($object)) {
         $supported[] = $extension;
       }
     }
 
     return $supported;
   }
 
 }
diff --git a/src/applications/search/storage/PhabricatorSavedQuery.php b/src/applications/search/storage/PhabricatorSavedQuery.php
index 3f75027888..837f4fde42 100644
--- a/src/applications/search/storage/PhabricatorSavedQuery.php
+++ b/src/applications/search/storage/PhabricatorSavedQuery.php
@@ -1,84 +1,91 @@
 <?php
 
 final class PhabricatorSavedQuery extends PhabricatorSearchDAO
   implements PhabricatorPolicyInterface {
 
   protected $parameters = array();
   protected $queryKey;
   protected $engineClassName;
 
   private $parameterMap = self::ATTACHABLE;
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_SERIALIZATION => array(
         'parameters' => self::SERIALIZATION_JSON,
       ),
       self::CONFIG_COLUMN_SCHEMA => array(
         'engineClassName' => 'text255',
         'queryKey' => 'text12',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_queryKey' => array(
           'columns' => array('queryKey'),
           'unique' => true,
         ),
       ),
     ) + parent::getConfiguration();
   }
 
   public function setParameter($key, $value) {
     $this->parameters[$key] = $value;
     return $this;
   }
 
   public function getParameter($key, $default = null) {
     return idx($this->parameters, $key, $default);
   }
 
   public function save() {
     if ($this->getEngineClassName() === null) {
       throw new Exception(pht('Engine class is null.'));
     }
 
     // Instantiate the engine to make sure it's valid.
     $this->newEngine();
 
     $serial = $this->getEngineClassName().serialize($this->parameters);
     $this->queryKey = PhabricatorHash::digestForIndex($serial);
 
     return parent::save();
   }
 
   public function newEngine() {
     return newv($this->getEngineClassName(), array());
   }
 
   public function attachParameterMap(array $map) {
     $this->parameterMap = $map;
     return $this;
   }
 
   public function getEvaluatedParameter($key) {
     return $this->assertAttachedKey($this->parameterMap, $key);
   }
 
+  public function newCopy() {
+    return id(new self())
+      ->setParameters($this->getParameters())
+      ->setQueryKey(null)
+      ->setEngineClassName($this->getEngineClassName());
+  }
+
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
     );
   }
 
   public function getPolicy($capability) {
     return PhabricatorPolicies::POLICY_PUBLIC;
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $viewer) {
     return false;
   }
 
 }