Work around parse_url() bug

Author: nicolas-grekas

Controller/RedirectController.php

@@ -119,14 +119,19 @@ public function urlRedirectAction(Request $request, string $path, bool $permanen
             $statusCode = $permanent ? 301 : 302;
         }
 
+        if (null === $scheme) {
+            $scheme = $request->getScheme();
+        }
+
+        if (str_starts_with($path, '//')) {
+            $path = $scheme.':'.$path;
+        }
+
         // redirect if the path is a full URL
         if (parse_url($path, \PHP_URL_SCHEME)) {
             return new RedirectResponse($path, $statusCode);
         }
 
-        if (null === $scheme) {
-            $scheme = $request->getScheme();
-        }
 
         if ($qs = $request->server->get('QUERY_STRING') ?: $request->getQueryString()) {
             if (!str_contains($path, '?')) {

Tests/Controller/RedirectControllerTest.php

@@ -183,6 +183,20 @@ public function testFullURLWithMethodKeep()
         $this->assertEquals(307, $returnResponse->getStatusCode());
     }
 
+    public function testProtocolRelative()
+    {
+        $request = new Request();
+        $controller = new RedirectController();
+
+        $returnResponse = $controller->urlRedirectAction($request, '//foo.bar/');
+        $this->assertRedirectUrl($returnResponse, 'http://foo.bar/');
+        $this->assertSame(302, $returnResponse->getStatusCode());
+
+        $returnResponse = $controller->urlRedirectAction($request, '//foo.bar/', false, 'https');
+        $this->assertRedirectUrl($returnResponse, 'https://foo.bar/');
+        $this->assertSame(302, $returnResponse->getStatusCode());
+    }
+
     public function testUrlRedirectDefaultPorts()
     {
         $host = 'www.example.com';