[HttpFoundation] Fix prepare request uri when it starts with double s…

…lashes

src/Symfony/Component/HttpFoundation/Request.php

@@ -1837,6 +1837,13 @@ protected function prepareRequestUri()
         } elseif ($this->server->has('REQUEST_URI')) {
             $requestUri = $this->server->get('REQUEST_URI');
 
+            // The REQUEST_URI starts with double slashes.
+            if (0 === strpos($requestUri, '//')) {
+                // We assume that the scheme and host are not provided (e.g. //path/too).
+                // Then patch the call to `parse_url()`.
+                $requestUri = "http://example.com$requestUri";
+            }
+
             // HTTP proxy reqs setup request URI with scheme and host [and port] + the URL path, only use URL path
             $uriComponents = parse_url($requestUri);
 

src/Symfony/Component/HttpFoundation/Tests/RequestTest.php

@@ -281,6 +281,10 @@ public function testCreateWithRequestUri()
         $request = Request::create('http://test.com/foo#bar');
         $request->server->set('REQUEST_URI', 'http://test.com/foo#bar');
         $this->assertEquals('http://test.com/foo', $request->getUri());
+
+        $request = Request::create('http://foo//bar/foo');
+        $request->server->set('REQUEST_URI', '//bar/foo');
+        $this->assertEquals('//bar/foo', $request->getPathInfo(), 'When the REQUEST_URI starts with double slashes.');
     }
 
     public function testCreateCheckPrecedence()