docs(schema): Add comment about the noLocation option (#1376)

Author: klausi

src/Plugin/GraphQL/Schema/AlterableComposableSchema.php

@@ -130,6 +130,9 @@ protected function getSchemaDocument(array $extensions = []) {
       $event,
       AlterSchemaDataEvent::EVENT_NAME
     );
+    // For caching and parsing big schemas we need to disable the creation of
+    // location nodes in the AST object to prevent serialization and memory
+    // errors. See https://github.com/webonyx/graphql-php/issues/1164
     $ast = Parser::parse(implode("\n\n", $event->getSchemaData()), ['noLocation' => TRUE]);
     if (empty($this->inDevelopment)) {
       $this->astCache->set($cid, $ast, CacheBackendInterface::CACHE_PERMANENT, ['graphql']);

src/Plugin/GraphQL/Schema/SdlSchemaPluginBase.php

@@ -174,6 +174,9 @@ protected function getSchemaDocument(array $extensions = []) {
     });
 
     $schema = array_merge([$this->getSchemaDefinition()], $extensions);
+    // For caching and parsing big schemas we need to disable the creation of
+    // location nodes in the AST object to prevent serialization and memory
+    // errors. See https://github.com/webonyx/graphql-php/issues/1164
     $ast = Parser::parse(implode("\n\n", $schema), ['noLocation' => TRUE]);
     if (empty($this->inDevelopment)) {
       $this->astCache->set($cid, $ast, CacheBackendInterface::CACHE_PERMANENT, ['graphql']);