Ensure RouteParser Always Present After Routing

Slim/Handlers/ErrorHandler.php

@@ -212,7 +212,7 @@ protected function determineStatusCode(): int
      * as willdurand/negotiation for any other situation.
      *
      * @param ServerRequestInterface $request
-     * @return string
+     * @return string|null
      */
     protected function determineContentType(ServerRequestInterface $request): ?string
     {
@@ -231,10 +231,15 @@ protected function determineContentType(ServerRequestInterface $request): ?strin
              * when multiple content types are provided via Accept header.
              */
             if ($current === 'text/plain' && $count > 1) {
-                return next($selectedContentTypes);
+                $next = next($selectedContentTypes);
+                if (is_string($next)) {
+                    return $next;
+                }
             }
 
-            return $current;
+            if (is_string($current)) {
+                return $current;
+            }
         }
 
         if (preg_match('/\+(json|xml)/', $acceptHeader, $matches)) {

Slim/Middleware/RoutingMiddleware.php

@@ -55,7 +55,6 @@ public function __construct(RouteResolverInterface $routeResolver, RouteParserIn
      */
     public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
     {
-        $request = $request->withAttribute(RouteContext::ROUTE_PARSER, $this->routeParser);
         $request = $this->performRouting($request);
         return $handler->handle($request);
     }
@@ -72,6 +71,8 @@ public function process(ServerRequestInterface $request, RequestHandlerInterface
      */
     public function performRouting(ServerRequestInterface $request): ServerRequestInterface
     {
+        $request = $request->withAttribute(RouteContext::ROUTE_PARSER, $this->routeParser);
+
         $routingResults = $this->resolveRoutingResultsFromRequest($request);
         $routeStatus = $routingResults->getRouteStatus();
 

tests/Routing/RouteRunnerTest.php

@@ -26,8 +26,12 @@ class RouteRunnerTest extends TestCase
     public function testRoutingIsPerformedIfRoutingResultsAreUnavailable()
     {
         $handler = (function (ServerRequestInterface $request, ResponseInterface $response) {
+            $routeParser = $request->getAttribute(RouteContext::ROUTE_PARSER);
+            $this->assertInstanceOf(RouteParser::class, $routeParser);
+
             $routingResults = $request->getAttribute(RouteContext::ROUTING_RESULTS);
             $this->assertInstanceOf(RoutingResults::class, $routingResults);
+
             return $response;
         })->bindTo($this);