fix(executor): Fix swapped errors and extensions property in execution results (drupal-graphql#1161)

Author: Kingdutch

config/install/graphql.settings.yml

@@ -0,0 +1 @@
+deprecated_swap_errors_and_extensions_in_results: false

config/schema/graphql.schema.yml

@@ -1,3 +1,12 @@
+graphql.settings:
+  type: config_object
+  label: "GraphQL Settings"
+  mapping:
+    deprecated_swap_errors_and_extensions_in_results:
+      type: boolean
+      label: "Return `errors` in the GraphQL response `extension` key and vice versa"
+      description: "Preserves behaviour that was caused by a bug that caused errors to appear in the extensions key of GraphQL results. Ensures misbehaving client implementations don't break by fixing this bug. Will be removed in 5.0.0"
+
 graphql.graphql_servers.*:
   type: config_entity
   label: 'Server'

graphql.install

@@ -63,3 +63,12 @@ function graphql_update_8001(): void {
     $server->save();
   }
 }
+
+/**
+ * Preserve incorrect error reporting behaviour for PR #1161.
+ */
+function graphql_update_8400() :void {
+  \Drupal::configFactory()->getEditable('graphql.settings')
+    ->set('deprecated_swap_errors_and_extensions_in_results', TRUE)
+    ->save();
+}

src/GraphQL/Execution/Executor.php

@@ -223,7 +223,13 @@ public function doExecute(): Promise {
     return $this->doExecuteUncached()->then(function ($result) {
       $this->context->mergeCacheMaxAge(0);
 
-      $result = new CacheableExecutionResult($result->data, $result->extensions, $result->errors);
+      // @todo keep only else case in 5.0.0.
+      if (\Drupal::config('graphql.settings')->get('deprecated_swap_errors_and_extensions_in_results')) {
+        $result = new CacheableExecutionResult($result->data, $result->extensions, $result->errors);
+      }
+      else {
+        $result = new CacheableExecutionResult($result->data, $result->errors, $result->extensions);
+      }
       $result->addCacheableDependency($this->context);
       return $result;
     });
@@ -246,7 +252,13 @@ protected function doExecuteCached($prefix) {
         $this->context->mergeCacheMaxAge(0);
       }
 
-      $result = new CacheableExecutionResult($result->data, $result->extensions, $result->errors);
+      // @todo keep only else case in 5.0.0.
+      if (\Drupal::config('graphql.settings')->get('deprecated_swap_errors_and_extensions_in_results')) {
+        $result = new CacheableExecutionResult($result->data, $result->extensions, $result->errors);
+      }
+      else {
+        $result = new CacheableExecutionResult($result->data, $result->errors, $result->extensions);
+      }
       $result->addCacheableDependency($this->context);
       if ($result->getCacheMaxAge() !== 0) {
         $this->cacheWrite($prefix, $result);