B2B-2659: Implement GraphQL Resolver Cache for cmsBlocks query

Author: danmooney2

app/code/Magento/GraphQlCache/Model/Plugin/Query/Resolver/Result/Cache.php

@@ -128,12 +128,16 @@ public function aroundResolve(
 
         $resolvedValue = $proceed($field, $context, $info, $value, $args);
 
-        $this->graphQlResolverCache->save(
-            $this->serializer->serialize($resolvedValue),
-            $cacheIdentityString,
-            $identityProvider->getIdentities($resolvedValue),
-            false, // use default lifetime directive
-        );
+        $identities = $identityProvider->getIdentities($resolvedValue);
+
+        if (count($identities)) {
+            $this->graphQlResolverCache->save(
+                $this->serializer->serialize($resolvedValue),
+                $cacheIdentityString,
+                $identities,
+                false, // use default lifetime directive
+            );
+        }
 
         return $resolvedValue;
     }

dev/tests/api-functional/testsuite/Magento/CmsGraphQl/Model/Resolver/BlockTest.php

@@ -14,6 +14,7 @@
 use Magento\GraphQlCache\Model\CacheId\CacheIdCalculator;
 use Magento\Store\Model\StoreManagerInterface;
 use Magento\TestFramework\ObjectManager;
+use Magento\TestFramework\TestCase\GraphQl\ResponseContainsErrorsException;
 use Magento\TestFramework\TestCase\GraphQlAbstract;
 use Magento\Widget\Model\Template\FilterEmulate;
 
@@ -48,6 +49,13 @@ protected function setUp(): void
         $this->storeManager = $objectManager->get(StoreManagerInterface::class);
     }
 
+    protected function tearDown(): void
+    {
+        $this->graphqlCache->clean();
+
+        parent::tearDown();
+    }
+
     /**
      * @magentoDataFixture Magento/Cms/_files/blocks.php
      */
@@ -246,6 +254,35 @@ public function testCmsBlockResolverCacheIsInvalidatedAfterChangingItsStoreView(
         );
     }
 
+    /**
+     * @magentoConfigFixture default/system/full_page_cache/caching_application 2
+     * @return void
+     */
+    public function testCmsBlockResolverCacheDoesNotSaveNonExistentCmsBlock()
+    {
+        $nonExistentBlock = ObjectManager::getInstance()->create(BlockInterface::class);
+        $nonExistentBlock->setIdentifier('non-existent-block');
+
+        $query = $this->getQuery([$nonExistentBlock->getIdentifier()]);
+
+        try {
+            $response = $this->graphQlQueryWithResponseHeaders($query);
+            $this->fail('Expected exception was not thrown');
+        } catch (ResponseContainsErrorsException $e) {
+            // expected exception
+        }
+
+        print_r($e->getResponseData());
+
+        $response['headers'] = $e->getResponseHeaders();
+
+        $cacheIdentityString = $this->getResolverCacheKeyFromResponseAndBlocks($response, [$nonExistentBlock]);
+
+        $this->assertFalse(
+            $this->graphqlCache->load($cacheIdentityString)
+        );
+    }
+
     private function getQuery(array $identifiers): string
     {
         $identifiersStr = $this->getQuotedBlockIdentifiersListAsString($identifiers);