[HttpFoundation] Fix notice when HTTP_PHP_AUTH_USER passed without pass

Author: Vitali Tsyrkin

ServerBag.php

@@ -89,7 +89,7 @@ public function getHeaders()
 
         // PHP_AUTH_USER/PHP_AUTH_PW
         if (isset($headers['PHP_AUTH_USER'])) {
-            $headers['AUTHORIZATION'] = 'Basic '.base64_encode($headers['PHP_AUTH_USER'].':'.$headers['PHP_AUTH_PW']);
+            $headers['AUTHORIZATION'] = 'Basic '.base64_encode($headers['PHP_AUTH_USER'].':'.($headers['PHP_AUTH_PW'] ?? ''));
         } elseif (isset($headers['PHP_AUTH_DIGEST'])) {
             $headers['AUTHORIZATION'] = $headers['PHP_AUTH_DIGEST'];
         }

Tests/ServerBagTest.php

@@ -57,6 +57,16 @@ public function testHttpPasswordIsOptional()
         ], $bag->getHeaders());
     }
 
+    public function testHttpPasswordIsOptionalWhenPassedWithHttpPrefix()
+    {
+        $bag = new ServerBag(['HTTP_PHP_AUTH_USER' => 'foo']);
+
+        $this->assertEquals([
+            'AUTHORIZATION' => 'Basic '.base64_encode('foo:'),
+            'PHP_AUTH_USER' => 'foo',
+        ], $bag->getHeaders());
+    }
+
     public function testHttpBasicAuthWithPhpCgi()
     {
         $bag = new ServerBag(['HTTP_AUTHORIZATION' => 'Basic '.base64_encode('foo:bar')]);