Explicitly decline to add commit authors as auditors from Herald

Summary:
Fixes T12304. If you have a Herald rule which tries to add a commit author as an auditor, it fails validation when trying to apply.

Stop trying to apply these transactions, and explicitly tell the user why. Differential already uses a similar ruleset around reviewers, but Audit was using older code.

Test Plan:
  - Wrote a Herald rule to add A, B and C as auditors.
  - Committed as A.
  - After change, saw B and C added with transacript guidance that A was the author.

{F3235660}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12304

Differential Revision: https://secure.phabricator.com/D17404

src/applications/diffusion/herald/DiffusionAuditorsHeraldAction.php

@@ -3,6 +3,7 @@
 abstract class DiffusionAuditorsHeraldAction
   extends HeraldAction {
 
+  const DO_AUTHORS = 'do.authors';
   const DO_ADD_AUDITORS = 'do.add-auditors';
 
   public function getActionGroupKey() {
@@ -19,6 +20,22 @@ abstract class DiffusionAuditorsHeraldAction
 
     $auditors = $object->getAudits();
 
+    // Don't try to add commit authors as auditors.
+    $authors = array();
+    foreach ($phids as $key => $phid) {
+      if ($phid == $object->getAuthorPHID()) {
+        $authors[] = $phid;
+        unset($phids[$key]);
+      }
+    }
+
+    if ($authors) {
+      $this->logEffect(self::DO_AUTHORS, $authors);
+      if (!$phids) {
+        return;
+      }
+    }
+
     $current = array();
     foreach ($auditors as $auditor) {
       if ($auditor->isInteresting()) {
@@ -53,6 +70,11 @@ abstract class DiffusionAuditorsHeraldAction
 
   protected function getActionEffectMap() {
     return array(
+      self::DO_AUTHORS => array(
+        'icon' => 'fa-user',
+        'color' => 'grey',
+        'name' => pht('Commit Author'),
+      ),
       self::DO_ADD_AUDITORS => array(
         'icon' => 'fa-user',
         'color' => 'green',
@@ -63,6 +85,10 @@ abstract class DiffusionAuditorsHeraldAction
 
   protected function renderActionEffectDescription($type, $data) {
     switch ($type) {
+      case self::DO_AUTHORS:
+        return pht(
+          'Declined to add commit author as auditor: %s.',
+          $this->renderHandleList($data));
       case self::DO_ADD_AUDITORS:
         return pht(
           'Added %s auditor(s): %s.',