GraphQL: improve error messange when mutation not allowed

Author: dunglas

features/graphql/mutation.feature

@@ -135,7 +135,7 @@ Feature: GraphQL mutation support
     Then the response status code should be 200
     And the response should be in JSON
     And the header "Content-Type" should be equal to "application/json"
-    And the JSON node "errors[0].message" should be equal to 'Item "/dummies/1" did not match expected type "ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Foo".'
+    And the JSON node "errors[0].message" should be equal to 'Item "/dummies/1" did not match expected type "Foo".'
 
   @dropSchema
   Scenario: Delete an item with composite identifiers through a mutation

src/GraphQl/Resolver/Factory/ItemMutationResolverFactory.php

@@ -85,7 +85,7 @@ public function __invoke(string $resourceClass = null, string $rootClass = null,
                 }
 
                 if ($resourceClass !== $this->getObjectClass($item)) {
-                    throw Error::createLocatedError(sprintf('Item "%s" did not match expected type "%s".', $args['input']['id'], $resourceClass), $info->fieldNodes, $info->path);
+                    throw Error::createLocatedError(sprintf('Item "%s" did not match expected type "%s".', $args['input']['id'], $resourceMetadata->getShortName()), $info->fieldNodes, $info->path);
                 }
             }