From a55fb95bd5aee66a94b3a2f07a0cf0de5a66e67f Mon Sep 17 00:00:00 2001
From: Bob Trahan <btrahan@phacility.com>
Date: Mon, 6 Apr 2015 11:45:43 -0700
Subject: [PATCH] Conpherence - only validate **new** participants when
 validating TYPE_PARTICIPANT transactions

Summary: Fixes T7693.

Test Plan: made a conpherence with my main test account and a throwaway test account. deleted the test account. removed myself from the thread. added myself back to the thread.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7693

Differential Revision: https://secure.phabricator.com/D12306
---
 src/applications/conpherence/editor/ConpherenceEditor.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/applications/conpherence/editor/ConpherenceEditor.php b/src/applications/conpherence/editor/ConpherenceEditor.php
index 0f5be65547..d896829ee0 100644
--- a/src/applications/conpherence/editor/ConpherenceEditor.php
+++ b/src/applications/conpherence/editor/ConpherenceEditor.php
@@ -587,9 +587,9 @@ final class ConpherenceEditor extends PhabricatorApplicationTransactionEditor {
         break;
       case ConpherenceTransactionType::TYPE_PARTICIPANTS:
         foreach ($xactions as $xaction) {
-          $phids = $this->getPHIDTransactionNewValue(
-            $xaction,
-            nonempty($object->getParticipantPHIDs(), array()));
+          $new_phids = $this->getPHIDTransactionNewValue($xaction, array());
+          $old_phids = nonempty($object->getParticipantPHIDs(), array());
+          $phids = array_diff($new_phids, $old_phids);
 
           if (!$phids) {
             continue;