Issue #3497935 by prudloff, smustgrave: Renderer::getCurrentRenderContext() triggers a TypeError when there is no current request

core/lib/Drupal/Core/Render/Renderer.php

@@ -607,6 +607,11 @@ class Renderer implements RendererInterface {
    */
   protected function getCurrentRenderContext() {
     $request = $this->requestStack->getCurrentRequest();
+
+    if (is_null($request)) {
+      return NULL;
+    }
+
     return static::$contextCollection[$request] ?? NULL;
   }
 

core/tests/Drupal/Tests/Core/Render/RendererTest.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace Drupal\Tests\Core\Render;
 
+use Drupal\Core\Render\RenderContext;
 use Drupal\Component\Render\MarkupInterface;
 use Drupal\Core\Access\AccessResult;
 use Drupal\Core\Access\AccessResultInterface;
@@ -1074,6 +1075,23 @@ class RendererTest extends RendererTestBase {
     ];
   }
 
+  /**
+   * @covers ::hasRenderContext
+   */
+  public function testHasRenderContext(): void {
+    // Tests with no render context.
+    $this->assertFalse($this->renderer->hasRenderContext());
+
+    // Tests in a render context.
+    $this->renderer->executeInRenderContext(new RenderContext(), function () {
+      $this->assertTrue($this->renderer->hasRenderContext());
+    });
+
+    // Test that the method works with no current request.
+    $this->requestStack->pop();
+    $this->assertFalse($this->renderer->hasRenderContext());
+  }
+
 }
 
 /**