avoid error during error reporting in chain router (#216)

the UrlGeneratorInterface::generate is not very specific about $parameters and allows non-arrays. simple solution as its only about reporting in an edge case of an error situation.

Author: dbu

src/ChainRouter.php

@@ -288,6 +288,10 @@ private function rebuildRequest($pathinfo)
     private function getErrorMessage($name, $router = null, $parameters = null)
     {
         if ($router instanceof VersatileGeneratorInterface) {
+            // the $parameters are not forced to be array, but versatile generator does typehint it
+            if (!is_array($parameters)) {
+                $parameters = [];
+            }
             $displayName = $router->getRouteDebugMessage($name, $parameters);
         } elseif (is_object($name)) {
             $displayName = method_exists($name, '__toString')