fix(travis): Install missing mysql (#920)

Author: klausi

.travis.yml

@@ -1,5 +1,9 @@
 language: php
 sudo: false
+dist: bionic
+
+services:
+  - mysql
 
 php:
   - 7.2

src/Plugin/GraphQL/DataProducer/Entity/EntityLoadMultiple.php

@@ -173,7 +173,10 @@ public function resolve($type, array $ids, $language, array $bundles, ?bool $acc
           /* @var $accessResult \Drupal\Core\Access\AccessResultInterface */
           $accessResult = $entity->access($accessOperation, $accessUser, TRUE);
           $context->addCacheableDependency($accessResult);
-          if ($accessResult->isForbidden()) {
+          // We need to call isAllowed() because isForbidden() returns FALSE
+          // for neutral access results, which is dangerous. Only an explicitly
+          // allowed result means that the user has access.
+          if (!$accessResult->isAllowed()) {
             unset($entities[$id]);
             continue;
           }

tests/src/Kernel/DataProducer/EntityMultipleTest.php

@@ -92,6 +92,10 @@ public function testResolveEntityLoadMultiple() {
       'type' => $this->node1->getEntityTypeId(),
       'bundles' => [$this->node1->bundle(), $this->node2->bundle()],
       'ids' => [$this->node1->id(), $this->node2->id(), $this->node3->id()],
+      // @todo We need to set these default values here to make the access
+      // handling work. Ideally that should not be needed.
+      'access' => TRUE,
+      'access_operation' => 'view',
     ]);
 
     $nids = array_values(array_map(function (NodeInterface $item) {