From 83ebbb519fa7cd6504c278fde0631891aebd49b6 Mon Sep 17 00:00:00 2001
From: Thalia <thalia.e.chan@googlemail.com>
Date: Tue, 16 Jul 2019 18:07:10 +0100
Subject: [PATCH] Check namespace exists in HTMLNamespacesMultiselectField
 validation

Bug: T219882
Change-Id: I710d0abed6bd40dcea5bdd1c59c8d936565961eb
---
 includes/htmlform/fields/HTMLNamespacesMultiselectField.php | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/includes/htmlform/fields/HTMLNamespacesMultiselectField.php b/includes/htmlform/fields/HTMLNamespacesMultiselectField.php
index 5eab6052a8..cbcd3ba34b 100644
--- a/includes/htmlform/fields/HTMLNamespacesMultiselectField.php
+++ b/includes/htmlform/fields/HTMLNamespacesMultiselectField.php
@@ -1,6 +1,7 @@
 <?php
 
 use MediaWiki\Widget\NamespacesMultiselectWidget;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Implements a tag multiselect input field for namespaces.
@@ -43,7 +44,10 @@ class HTMLNamespacesMultiselectField extends HTMLSelectNamespace {
 		}
 
 		foreach ( $namespaces as $namespace ) {
-			if ( $namespace < 0 ) {
+			if (
+				$namespace < 0 ||
+				!MediaWikiServices::getInstance()->getNamespaceInfo()->exists( $namespace )
+			) {
 				return $this->msg( 'htmlform-select-badoption' );
 			}
 
-- 
2.20.1