Index: src/wp-admin/includes/misc.php
===================================================================
--- src/wp-admin/includes/misc.php	(revision 40958)
+++ src/wp-admin/includes/misc.php	(working copy)
@@ -71,8 +71,9 @@
 		return $result;
 	}
 
-	if ( $markerdata = explode( "\n", implode( '', file( $filename ) ) ));
-	{
+	$markerdata = explode( "\n", implode( '', file( $filename ) ) );
+
+	if ( ! empty( $markerdata ) ) {
 		$state = false;
 		foreach ( $markerdata as $markerline ) {
 			if (strpos($markerline, '# END ' . $marker) !== false)