Ticket #16849: 16489.3.patch

src/wp-admin/includes/file.php

@@ -263 +263 @@
          */
         $file = apply_filters( "{$action}_prefilter", $file );
 
+        /**
+         * Filters the ovverride action for a file before it is uploaded to WordPress.
+         *
+         * The dynamic portion of the hook name, `$action`, refers to the post action.
+         *
+         * @param array $file An array of overrides actions.
+         */
+        $overrides = apply_filters( "{$action}_overrides", $overrides );
+
         // You may define your own function and pass the name in $overrides['upload_error_handler']
         $upload_error_handler = 'wp_handle_upload_error';
         if ( isset( $overrides['upload_error_handler'] ) ) {