Ticket #21526: 21526-post_capabilities_array_merge.patch

wp-includes/post.php

@@ -1180 +1180 @@
                 $default_capabilities = array_merge( $default_capabilities, $default_capabilities_for_mapping );
         }
 
-        $capabilities = array_merge( $default_capabilities, $args->capabilities );
+        $capabilities = array_merge( $default_capabilities, (array)$args->capabilities );
 
         // Remember meta capabilities for future reference.
         if ( $args->map_meta_cap )