Remove (most) support for 'differential.attach-task-class'

Summary:
After D814 and D829, you should be able to implement this logic in the
didWriteRevision() method of the field.

Note that the attacher is still referenced in
ConduitAPI_differential_updatetaskrevisionassoc_Method. This method should
probably be moved to facebook/ since it's pretty Facebook-specific.

No rush on any of this, it's not hurting anything.

Test Plan:
  - Hit differential.getcommitmessage
  - Ran 'arc diff'

Reviewers: jungejason, tuomaspelkonen, aran

Reviewed By: jungejason

CC: aran, jungejason

Differential Revision: 830

src/applications/conduit/method/differential/getcommitmessage/ConduitAPI_differential_getcommitmessage_Method.php

@@ -76,10 +76,6 @@ class ConduitAPI_differential_getcommitmessage_Method extends ConduitAPIMethod {
 
         $aux_field = idx($aux_fields, $field);
         if (!$aux_field) {
-          if ($field == 'tasks') {
-            // TODO: Remove, backcompat for Facebook.
-            continue;
-          }
           throw new Exception(
             "Commit message includes field '{$field}' which does not ".
             "correspond to any configured field.");

src/applications/differential/editor/revision/DifferentialRevisionEditor.php

@@ -31,7 +31,6 @@ class DifferentialRevisionEditor {
   protected $diff;
   protected $comments;
   protected $silentUpdate;
-  protected $tasks = null;
 
   private $auxiliaryFields = array();
 
@@ -58,11 +57,6 @@ class DifferentialRevisionEditor {
     $editor->addDiff($diff, null);
     $editor->save();
 
-    // Tasks can only be updated after revision has been saved to the
-    // database. Currently tasks are updated only when a revision is created.
-    // UI must be used to modify tasks after creating one.
-    $editor->updateTasks();
-
     return $revision;
   }
 
@@ -85,12 +79,6 @@ class DifferentialRevisionEditor {
 
     foreach ($fields as $field => $value) {
       if (empty($aux_fields[$field])) {
-        if ($field == 'tasks') {
-          // TODO: Deprecate once this can be fully supported with custom
-          // fields. This is just to prevent a backcompat break for Facebook.
-          $this->setTasks($value);
-          continue;
-        }
         throw new Exception(
           "Parsed commit message contains unrecognized field '{$field}'.");
       }
@@ -120,10 +108,6 @@ class DifferentialRevisionEditor {
     return $this;
   }
 
-  public function setTasks(array $tasks) {
-    $this->tasks = $tasks;
-  }
-
   public function addDiff(DifferentialDiff $diff, $comments) {
     if ($diff->getRevisionID() &&
         $diff->getRevisionID() != $this->getRevision()->getID()) {
@@ -673,21 +657,6 @@ class DifferentialRevisionEditor {
     return $comment;
   }
 
-  private function updateTasks() {
-    if ($this->tasks) {
-      $task_class = PhabricatorEnv::getEnvConfig(
-        'differential.attach-task-class');
-      if ($task_class) {
-        PhutilSymbolLoader::loadClass($task_class);
-        $task_attacher = newv($task_class, array());
-        $ret = $task_attacher->attachTasksToRevision(
-          $this->actorPHID,
-          $this->revision,
-          $this->tasks);
-      }
-    }
-  }
-
   private function updateAuxiliaryFields() {
     $aux_map = array();
     foreach ($this->auxiliaryFields as $aux_field) {

src/applications/differential/editor/revision/__init__.php

@@ -26,7 +26,6 @@ phutil_require_module('phabricator', 'infrastructure/env');
 phutil_require_module('phabricator', 'storage/qsprintf');
 phutil_require_module('phabricator', 'storage/queryfx');
 
-phutil_require_module('phutil', 'symbols');
 phutil_require_module('phutil', 'utils');