Materialize parent project memberships

Summary:
Ref T10010. Subprojects have the following general membership rule: if you are a member of a subproject ("Engineering > Backend"), you are also a member of the parent project.

It would be unreasonably difficult to implement this rule directly in SQL when querying `withMemberPHIDs()`, because we'd have to do an arbitrarily large number of arbitrarily deep joins, or fetch and then requery a lot of data.

Instead, introduce "materailized members", which are just a copy of all the effective members of a project. When a subproject has a membership change, we go recompute the effective membership of all the parent projects. Then we can just JOIN to satisfy `withMemberPHIDs()`.

Having this process avialable will also be useful in the future, when a project's membership might be defined by some external source.

Also make milestones mostly work like we'd expect them to with respect to membership and visibility.

Test Plan:
  - Added and executed unit tests.
  - Changed project members, verified materialized members populated correctly in the database.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10010

Differential Revision: https://secure.phabricator.com/D14863

src/applications/project/engineextension/PhabricatorProjectsMembershipIndexEngineExtension.php

@@ -0,0 +1,98 @@
+<?php
+
+final class PhabricatorProjectsMembershipIndexEngineExtension
+  extends PhabricatorIndexEngineExtension {
+
+  const EXTENSIONKEY = 'project.members';
+
+  public function getExtensionName() {
+    return pht('Project Members');
+  }
+
+  public function shouldIndexObject($object) {
+    if (!($object instanceof PhabricatorProject)) {
+      return false;
+    }
+
+    return true;
+  }
+
+  public function indexObject(
+    PhabricatorIndexEngine $engine,
+    $object) {
+
+    $this->rematerialize($object);
+  }
+
+  public function rematerialize(PhabricatorProject $project) {
+    $materialize = $project->getAncestorProjects();
+    array_unshift($materialize, $project);
+
+    foreach ($materialize as $project) {
+      $this->materializeProject($project);
+    }
+  }
+
+  private function materializeProject(PhabricatorProject $project) {
+    if ($project->isMilestone()) {
+      return;
+    }
+
+    $material_type = PhabricatorProjectMaterializedMemberEdgeType::EDGECONST;
+    $member_type = PhabricatorProjectProjectHasMemberEdgeType::EDGECONST;
+
+    $project_phid = $project->getPHID();
+
+    $descendants = id(new PhabricatorProjectQuery())
+      ->setViewer($this->getViewer())
+      ->withAncestorProjectPHIDs(array($project->getPHID()))
+      ->withIsMilestone(false)
+      ->withHasSubprojects(false)
+      ->execute();
+    $descendant_phids = mpull($descendants, 'getPHID');
+
+    if ($descendant_phids) {
+      $source_phids = $descendant_phids;
+      $has_subprojects = true;
+    } else {
+      $source_phids = array($project->getPHID());
+      $has_subprojects = false;
+    }
+
+    $conn_w = $project->establishConnection('w');
+
+    $project->openTransaction();
+
+      // Delete any existing materialized member edges.
+      queryfx(
+        $conn_w,
+        'DELETE FROM %T WHERE src = %s AND type = %s',
+        PhabricatorEdgeConfig::TABLE_NAME_EDGE,
+        $project_phid,
+        $material_type);
+
+      // Copy current member edges to create new materialized edges.
+      queryfx(
+        $conn_w,
+        'INSERT IGNORE INTO %T (src, type, dst, dateCreated, seq)
+          SELECT %s, %d, dst, dateCreated, seq FROM %T
+          WHERE src IN (%Ls) AND type = %d',
+        PhabricatorEdgeConfig::TABLE_NAME_EDGE,
+        $project_phid,
+        $material_type,
+        PhabricatorEdgeConfig::TABLE_NAME_EDGE,
+        $source_phids,
+        $member_type);
+
+      // Update the hasSubprojects flag.
+      queryfx(
+        $conn_w,
+        'UPDATE %T SET hasSubprojects = %d WHERE id = %d',
+        $project->getTableName(),
+        (int)$has_subprojects,
+        $project->getID());
+
+    $project->saveTransaction();
+  }
+
+}