fix(dataproducer): Populate context default values before resolving

src/Plugin/GraphQL/DataProducer/DataProducerPluginBase.php

@@ -51,11 +51,26 @@ public function resolveField(FieldContext $field) {
       throw new \LogicException('Missing data producer resolve method.');
     }
 
-    $context = $this->getContextValues();
+    $context = $this->getContextValuesWithDefaults();
     return call_user_func_array(
       [$this, 'resolve'],
       array_values(array_merge($context, [$field]))
     );
   }
 
+  /**
+   * Initializes all contexts and populates default values.
+   *
+   * We cannot use ::getContextValues() here because it does not work with
+   * default_value.
+   */
+  public function getContextValuesWithDefaults() {
+    $values = [];
+    foreach ($this->getContextDefinitions() as $name => $definition) {
+      $values[$name] = $this->getContext($name)->getContextValue();
+    }
+
+    return $values;
+  }
+
 }

tests/src/Kernel/DataProducer/DefaultValueTest.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Drupal\Tests\graphql\Kernel\DataProducer;
+
+use Drupal\Tests\graphql\Kernel\GraphQLTestBase;
+
+/**
+ * Context default value test.
+ *
+ * @group graphql
+ */
+class DefaultValueTest extends GraphQLTestBase {
+
+
+  /**
+   * Test that the entity_load data producer has the correct default values.
+   */
+  public function testEntityLoadDefaultValue(): void {
+    $manager = $this->container->get('plugin.manager.graphql.data_producer');
+    $plugin = $manager->createInstance('entity_load');
+    // Only type is required.
+    $plugin->setContextValue('type', 'node');
+    $context_values = $plugin->getContextValuesWithDefaults();
+    $this->assertSame(TRUE, $context_values['access']);
+    $this->assertSame('view', $context_values['access_operation']);
+  }
+
+}