Show task duplicates as related objects in Maniphest and migrate old duplicates

Summary: Does the UI work that's part of T12234 and adds migrations for both of the old-style duplicate transactions.

Test Plan:
 - Started with a clean DB.
 - Checked out really old code that marks tasks as dupes using comments.
 - Made a bunch of tasks and closed some as dupes. Made a bunch of additional comments.
 - Checked out D10427 and did a `storage upgrade`.
 - Made a bunch more new tasks and dupes.
 - Snapshotted DB.
 - Ran migration repeatedly until all expected edges showed up in the `phabricator_maniphest.edge`table.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T12234

Differential Revision: https://secure.phabricator.com/D18037

resources/sql/autopatches/20170528.maniphestdupes.php

@@ -0,0 +1,68 @@
+<?php
+
+$table = new ManiphestTransaction();
+$add_edges = array();
+
+foreach (new LiskMigrationIterator($table) as $txn) {
+  $txn_type = $txn->getTransactionType();
+
+  if ($txn_type == 'mergedinto') {
+    // dupe handling as implemented in D10427, which creates a specific txn
+    $add_edges[] = array(
+      'src' => $txn->getObjectPHID(),
+      'dst' => $txn->getNewValue(),
+    );
+  } else if ($txn_type == 'status' && $txn->getNewValue() == 'duplicate') {
+    // dupe handling as originally implemented, which just changes the status
+    // and adds a comment
+    $src_phid = $txn->getObjectPHID();
+
+    // get all the comment transactions associated with this task
+    $viewer = PhabricatorUser::getOmnipotentUser();
+    $comment_txns = id(new ManiphestTransactionQuery())
+      ->setViewer($viewer)
+      ->withObjectPHIDs(array($src_phid))
+      ->needComments(true)
+      ->execute();
+
+    // check each comment, looking for the "Merged Into" message
+    foreach ($comment_txns as $comment_txn) {
+      if ($comment_txn->hasComment()) {
+        $comment = $comment_txn->getComment()->getContent();
+        $pattern = '/^\xE2\x9C\x98 Merged into T(\d+)\.$/';
+        $matches = array();
+
+        if (preg_match($pattern, $comment, $matches)) {
+          $dst_task = id(new ManiphestTaskQuery())
+            ->setViewer($viewer)
+            ->withIDs(array($matches[1]))
+            ->executeOne();
+
+          if ($dst_task) {
+            $dst_phid = $dst_task->getPHID();
+            $add_edges[] = array(
+              'src' => $src_phid,
+              'dst' => $dst_phid,
+            );
+          }
+        }
+      }
+    }
+  }
+}
+
+if ($add_edges) {
+  foreach ($add_edges as $edge) {
+    $src_phid = $edge['src'];
+    $dst_phid = $edge['dst'];
+
+    $type = ManiphestTaskIsDuplicateOfTaskEdgeType::EDGECONST;
+    try {
+      $editor = id(new PhabricatorEdgeEditor())
+        ->addEdge($src_phid, $type, $dst_phid)
+        ->save();
+    } catch (PhabricatorEdgeCycleException $ex) {
+      // Some earlier or later merge made this invalid, just skip it.
+    }
+  }
+}

src/applications/maniphest/controller/ManiphestTaskDetailController.php

@@ -36,6 +36,7 @@ final class ManiphestTaskDetailController extends ManiphestController {
       ManiphestTaskHasMockEdgeType::EDGECONST,
       PhabricatorObjectMentionedByObjectEdgeType::EDGECONST,
       PhabricatorObjectMentionsObjectEdgeType::EDGECONST,
+      ManiphestTaskHasDuplicateTaskEdgeType::EDGECONST,
     );
 
     $phid = $task->getPHID();
@@ -159,6 +160,7 @@ final class ManiphestTaskDetailController extends ManiphestController {
 
     $related_tabs[] = $this->newMocksTab($task, $query);
     $related_tabs[] = $this->newMentionsTab($task, $query);
+    $related_tabs[] = $this->newDuplicatesTab($task, $query);
 
     $tab_view = null;
 
@@ -553,6 +555,32 @@ final class ManiphestTaskDetailController extends ManiphestController {
       ->appendChild($view);
   }
 
+  private function newDuplicatesTab(
+    ManiphestTask $task,
+    PhabricatorEdgeQuery $edge_query) {
+
+    $in_type = ManiphestTaskHasDuplicateTaskEdgeType::EDGECONST;
+    $in_phids = $edge_query->getDestinationPHIDs(array(), array($in_type));
+
+    $viewer = $this->getViewer();
+    $in_handles = $viewer->loadHandles($in_phids);
+    $in_handles = $this->getCompleteHandles($in_handles);
+
+    $view = new PHUIPropertyListView();
+
+    if (!count($in_handles)) {
+      return null;
+    }
+
+    $view->addProperty(
+      pht('Duplicates Merged Here'), $in_handles->renderList());
+
+    return id(new PHUITabView())
+      ->setName(pht('Duplicates'))
+      ->setKey('duplicates')
+      ->appendChild($view);
+  }
+
   private function getCompleteHandles(PhabricatorHandleList $handles) {
     $phids = array();