Notice: Trying to access array offset on value of type null in Drupal\Core\Menu\Plugin\Block\LocalTasksBlock->blockSubmit() (line 153 of core/lib/Drupal/Core/Menu/Plugin/Block/LocalTasksBlock.php).

jernejmramor 🐛 Notice: Trying to access array offset on value of type null in Drupal\Core\Menu\Plugin\Block\LocalTasksBlock->blockSubmit() (line 153 of core/lib/Drupal/Core/Menu/Plugin/Block/LocalTasksBlock.php). Active

This is the context config.

I've run into this same problem on Drupal 10.1.5 and Context 5.0.0-rc1. Has there been any movement on getting a fix/patch for this?

Error message is for the SystemBrandingBlock:

Warning: Trying to access array offset on value of type null in Drupal\system\Plugin\Block\SystemBrandingBlock->blockSubmit() (line 142 of core/modules/system/src/Plugin/Block/SystemBrandingBlock.php).
Drupal\system\Plugin\Block\SystemBrandingBlock->blockSubmit(Array, Object) (Line: 234)
Drupal\Core\Block\BlockBase->submitConfigurationForm(Array, Object) (Line: 756)
Drupal\context\Plugin\ContextReaction\Blocks->submitConfigurationForm(Array, Object) (Line: 207)
Drupal\context_ui\Form\ContextFormBase->handleReactions(Array, Object) (Line: 150)
Drupal\context_ui\Form\ContextFormBase->submitForm(Array, Object)
call_user_func_array(Array, Array) (Line: 114)
Drupal\Core\Form\FormSubmitter->executeSubmitHandlers(Array, Object) (Line: 52)
Drupal\Core\Form\FormSubmitter->doSubmitForm(Array, Object) (Line: 597)
Drupal\Core\Form\FormBuilder->processForm('context_edit_form', Array, Object) (Line: 325)
Drupal\Core\Form\FormBuilder->buildForm(Object, Object) (Line: 73)
Drupal\Core\Controller\FormController->getContentResult(Object, Object) (Line: 39)
Drupal\layout_builder\Controller\LayoutBuilderHtmlEntityFormController->getContentResult(Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 617)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 182)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object, 1, 1) (Line: 704)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

This issue still exists for me on both 8.x-4.x and 5.0.0-rc1

Warning: Trying to access array offset on value of type null in Drupal\system\Plugin\Block\SystemBrandingBlock->blockSubmit() (line 142 of core/modules/system/src/Plugin/Block/SystemBrandingBlock.php).
Warning: Trying to access array offset on value of type null in Drupal\system\Plugin\Block\SystemBrandingBlock->blockSubmit() (line 143 of core/modules/system/src/Plugin/Block/SystemBrandingBlock.php).
Warning: Trying to access array offset on value of type null in Drupal\system\Plugin\Block\SystemBrandingBlock->blockSubmit() (line 144 of core/modules/system/src/Plugin/Block/SystemBrandingBlock.php).

This will happen for all Blocks, that has a hierarchical structure in the form.

$block_state = (new FormState())->setValues($configuration);
$block->submitConfigurationForm($form, $block_state);

Here the FormState is initialised with the $configuration values which is a simple array, but if you check the SystemBrandingBlock or LocalTasksBlock blockSubmits, you can see that the values from the fieldset are moved to the top level values.

So this is a general issue, and will show up for every block which has hierarchical form structure.