Return milestone information in project.search

Summary:
Ref T12074.

  - `project.search` now returns milestones by default.
  - A new constraint, `isMilestone`, allows filtering to milestones, non-milestones, or both (API and web UI).
  - `project.search` now returns a milestone number for milestones, or `null` for non-milestones.

NOTE: Existing custom saved queries in projects which previously did not return milestones now will. I expect this to have little-to-no impact on users, and these queries are easy to correct, but I'll note this in changelogs.

Test Plan:
  - Ran various queries with `project.search` and in the web UI, searching for milestones, non-milestones, and both.
  - Web UI default behavior (no milestones) is unchanged, but you can now get milestones if you want them.
  - Queried a milestone by ID/PHID via API.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12074

Differential Revision: https://secure.phabricator.com/D17153

src/applications/project/query/PhabricatorProjectSearchEngine.php

@@ -13,8 +13,7 @@ final class PhabricatorProjectSearchEngine
 
   public function newQuery() {
     return id(new PhabricatorProjectQuery())
-      ->needImages(true)
-      ->withIsMilestone(false);
+      ->needImages(true);
   }
 
   protected function buildCustomSearchFields() {
@@ -34,6 +33,17 @@ final class PhabricatorProjectSearchEngine
         ->setLabel(pht('Status'))
         ->setKey('status')
         ->setOptions($this->getStatusOptions()),
+      id(new PhabricatorSearchThreeStateField())
+        ->setLabel(pht('Milestones'))
+        ->setKey('isMilestone')
+        ->setOptions(
+          pht('(Show All)'),
+          pht('Show Only Milestones'),
+          pht('Hide Milestones'))
+        ->setDescription(
+          pht(
+            'Pass true to find only milestones, or false to omit '.
+            'milestones.')),
       id(new PhabricatorSearchCheckboxesField())
         ->setLabel(pht('Icons'))
         ->setKey('icons')
@@ -77,6 +87,10 @@ final class PhabricatorProjectSearchEngine
       $query->withColors($map['colors']);
     }
 
+    if ($map['isMilestone'] !== null) {
+      $query->withIsMilestone($map['isMilestone']);
+    }
+
     return $query;
   }
 
@@ -103,6 +117,9 @@ final class PhabricatorProjectSearchEngine
 
     $viewer_phid = $this->requireViewer()->getPHID();
 
+    // By default, do not show milestones in the list view.
+    $query->setParameter('isMilestone', false);
+
     switch ($query_key) {
       case 'all':
         return $query;

src/applications/project/storage/PhabricatorProject.php

@@ -741,6 +741,10 @@ final class PhabricatorProject extends PhabricatorProjectDAO
         ->setKey('slug')
         ->setType('string')
         ->setDescription(pht('Primary slug/hashtag.')),
+      id(new PhabricatorConduitSearchFieldSpecification())
+        ->setKey('milestone')
+        ->setType('int?')
+        ->setDescription(pht('For milestones, milestone sequence number.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('icon')
         ->setType('map<string, wild>')
@@ -756,9 +760,16 @@ final class PhabricatorProject extends PhabricatorProjectDAO
     $color_key = $this->getColor();
     $color_name = PhabricatorProjectIconSet::getColorName($color_key);
 
+    if ($this->isMilestone()) {
+      $milestone = (int)$this->getMilestoneNumber();
+    } else {
+      $milestone = null;
+    }
+
     return array(
       'name' => $this->getName(),
       'slug' => $this->getPrimarySlug(),
+      'milestone' => $milestone,
       'icon' => array(
         'key' => $this->getDisplayIconKey(),
         'name' => $this->getDisplayIconName(),