Correct a bug where milestone "spacePHID" columns could become desynchronized

Summary:
Depends on D20041. See PHI1046. If you do this:

- Create a parent project called "Crab" in Space 1.
- Create a milestone called "Left Claw".
- Shift "Crab" to Space 2.
- Create a milestone called "Right Claw".

...you currently end up with "Left Claw" in the wrong `spacePHID` in the database. At the application level it's in the correct space, but when we `WHERE ... AND spacePHID IN (...)` we can incorrectly filter it out.

Test Plan:
  - Did the above setup.
  - Saved "Crab", saw the space fix itself.
  - Put things back in the broken state.
  - Ran the migration script, saw things fix themselves again.

Reviewers: amckinley

Reviewed By: amckinley

Subscribers: aeiser, PHID-OPKG-gm6ozazyms6q6i22gyam

Differential Revision: https://secure.phabricator.com/D20063

Author: epriestley

resources/sql/autopatches/20190129.project.01.spaces.php

@@ -0,0 +1,18 @@
+<?php
+
+// See PHI1046. The "spacePHID" column for milestones may have fallen out of
+// sync; correct all existing values.
+
+$table = new PhabricatorProject();
+$conn = $table->establishConnection('w');
+$table_name = $table->getTableName();
+
+foreach (new LiskRawMigrationIterator($conn, $table_name) as $project_row) {
+  queryfx(
+    $conn,
+    'UPDATE %R SET spacePHID = %ns
+      WHERE parentProjectPHID = %s AND milestoneNumber IS NOT NULL',
+    $table,
+    $project_row['spacePHID'],
+    $project_row['phid']);
+}

src/applications/project/editor/PhabricatorProjectTransactionEditor.php

@@ -249,6 +249,17 @@ protected function applyFinalEffects(
         ->rematerialize($new_parent);
     }
 
+    // See PHI1046. Milestones are always in the Space of their parent project.
+    // Synchronize the database values to match the application values.
+    $conn = $object->establishConnection('w');
+    queryfx(
+      $conn,
+      'UPDATE %R SET spacePHID = %ns
+        WHERE parentProjectPHID = %s AND milestoneNumber IS NOT NULL',
+      $object,
+      $object->getSpacePHID(),
+      $object->getPHID());
+
     return parent::applyFinalEffects($object, $xactions);
   }