Merge branch 'feature/nullable-resource' into 'master'

Allow null single resource response

See merge request undabot/json-api-symfony!44

Author: penovic

src/Http/Model/Response/ResourceResponse.php

@@ -11,7 +11,7 @@
 
 final class ResourceResponse
 {
-    /** @var ResourceInterface */
+    /** @var null|ResourceInterface */
     private $primaryResource;
 
     /** @var null|ResourceCollectionInterface */
@@ -24,7 +24,7 @@ final class ResourceResponse
     private $links;
 
     public function __construct(
-        ResourceInterface $primaryResource,
+        ?ResourceInterface $primaryResource,
         ?ResourceCollectionInterface $includedResources = null,
         ?MetaInterface $meta = null,
         ?LinkCollectionInterface $links = null
@@ -35,7 +35,7 @@ public function __construct(
         $this->links = $links;
     }
 
-    public function getPrimaryResource(): ResourceInterface
+    public function getPrimaryResource(): ?ResourceInterface
     {
         return $this->primaryResource;
     }

src/Http/Service/Responder/AbstractResponder.php

@@ -101,7 +101,12 @@ public function resource(
         array $meta = null,
         array $links = null
     ): ResourceResponse {
-        $resource = $this->encodeData($primaryData);
+        /**
+         * resource response can be single resource or null.
+         *
+         * @see https://jsonapi.org/format/#fetching-resources-responses-200
+         */
+        $resource = null === $primaryData ? null : $this->encodeData($primaryData);
 
         return new ResourceResponse(
             $resource,

tests/Unit/Http/Service/EventSubscriber/ViewResponseSubscriberTest.php

@@ -86,6 +86,11 @@ public function controllerResultProvider(): \Generator
             true,
         ];
 
+        yield 'Null ResourceResponse returned by controller' => [
+            new ResourceResponse(null),
+            true,
+        ];
+
         yield 'ResourceValidationErrorsResponse returned by controller' => [
             new ResourceValidationErrorsResponse(new ErrorCollection([])),
             true,