When destroying an object, destroy its Herald transcripts too

Summary: Ref T5915. Make `bin/remove destroy` a bit more thorough, since Herald transcripts can have field information in them.

Test Plan: Used `bin/remove destroy` to nuke revisions, saw their transcripts vanish too.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T5915

Differential Revision: https://secure.phabricator.com/D10306

src/__phutil_library_map__.php

@@ -3575,6 +3575,7 @@ phutil_register_library_map(array(
     'HeraldTranscript' => array(
       'HeraldDAO',
       'PhabricatorPolicyInterface',
+      'PhabricatorDestructibleInterface',
     ),
     'HeraldTranscriptController' => 'HeraldController',
     'HeraldTranscriptGarbageCollector' => 'PhabricatorGarbageCollector',

src/applications/herald/storage/transcript/HeraldTranscript.php

@@ -1,7 +1,9 @@
 <?php
 
 final class HeraldTranscript extends HeraldDAO
-  implements PhabricatorPolicyInterface {
+  implements
+    PhabricatorPolicyInterface,
+    PhabricatorDestructibleInterface {
 
   protected $objectTranscript;
   protected $ruleTranscripts = array();
@@ -196,4 +198,16 @@ final class HeraldTranscript extends HeraldDAO
   }
 
 
+/* -(  PhabricatorDestructibleInterface  )----------------------------------- */
+
+
+  public function destroyObjectPermanently(
+    PhabricatorDestructionEngine $engine) {
+
+    $this->openTransaction();
+      $this->delete();
+    $this->saveTransaction();
+  }
+
+
 }

src/applications/system/engine/PhabricatorDestructionEngine.php

@@ -48,6 +48,19 @@ final class PhabricatorDestructionEngine extends Phobject {
       }
     }
 
+    // Nuke any Herald transcripts of the object, because they may contain
+    // field data.
+
+    // TODO: Define an interface so we don't have to do this for transactions
+    // and other objects with no Herald adapters?
+    $transcripts = id(new HeraldTranscript())->loadAllWhere(
+      'objectPHID = %s',
+      $object_phid);
+    foreach ($transcripts as $transcript) {
+      $transcript->destroyObjectPermanently($this);
+    }
+
+    // TODO: Remove stuff from search indexes?
     // TODO: PhabricatorFlaggableInterface
     // TODO: PhabricatorTokenReceiverInterface
   }