From ffc70d0791e75bdf9d75846e503020a857b3d65c Mon Sep 17 00:00:00 2001
From: =?utf8?q?Gerg=C5=91=20Tisza?= <tgr.huwiki@gmail.com>
Date: Sun, 6 Jan 2019 18:03:07 -0800
Subject: [PATCH] Special:UserRights: Fix handling of empty conflict check
 value

Bug: T164211
Change-Id: I6b710a25e9be29497846fafe39c916d480989a96
---
 includes/specials/SpecialUserrights.php | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/includes/specials/SpecialUserrights.php b/includes/specials/SpecialUserrights.php
index 0f9ded382a..94b8184d5f 100644
--- a/includes/specials/SpecialUserrights.php
+++ b/includes/specials/SpecialUserrights.php
@@ -170,10 +170,11 @@ class UserrightsPage extends SpecialPage {
 				$targetUser->clearInstanceCache(); // T40989
 			}
 
-			$checkValue = explode( ',', $request->getVal( 'conflictcheck-originalgroups' ) );
+			$conflictCheck = $request->getVal( 'conflictcheck-originalgroups' );
+			$conflictCheck = ( $conflictCheck === '' ) ? [] : explode( ',', $conflictCheck );
 			$userGroups = $targetUser->getGroups();
 
-			if ( $userGroups !== $checkValue ) {
+			if ( $userGroups !== $conflictCheck ) {
 				$out->addWikiMsg( 'userrights-conflict' );
 			} else {
 				$status = $this->saveUserGroups(
-- 
2.20.1