Setting "Allowed number of values" in field storage settings when using paragraphs_limits breaks edit pages

Added a trivial fix that covers the case when $elements['widget']['add_more'] is empty.

Applies cleanly on my composer site and fixes the issue for me.

As for the Steps to reproduce
I have a field config that includes:

settings:
  handler: paragraphs_limits
  handler_settings:
    target_bundles:
      h4d_commerce_house: h4d_commerce_house
      h4d_commerce_consumer: h4d_commerce_consumer
      h4d_commerce_business: h4d_commerce_business
    negate: 0
    target_bundles_drag_drop:
      h4d_commerce_house:
        weight: 0
        enabled: true
        lower_limit: 0
        upper_limit: 1
      h4d_commerce_consumer:
        weight: 1
        enabled: true
        lower_limit: 0
        upper_limit: 1
      h4d_commerce_business:
        weight: 2
        enabled: true
        lower_limit: 0
        upper_limit: 1

When creating/editing content, I clicked to add a paragraph (button widget), but the form won't show. Instead I get a warning and an error. The patch fixes this for me.

Warning: Undefined array key "add_more" in _paragraphs_limits_disallow_limited_paragraphs() (line 90 of /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs_limits/paragraphs_limits.module)
#0 /home/andi/git/site-h4d-greenopolis/web/core/includes/bootstrap.inc(166): _drupal_error_handler_real()
#1 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs_limits/paragraphs_limits.module(90): _drupal_error_handler()
#2 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs_limits/paragraphs_limits.module(45): _paragraphs_limits_disallow_limited_paragraphs()
#3 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Extension/ModuleHandler.php(552): paragraphs_limits_field_widget_complete_paragraphs_form_alter()
#4 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/hux/src/HuxModuleHandler.php(163): Drupal\Core\Extension\ModuleHandler->alter()
#5 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Field/WidgetBase.php(156): Drupal\hux\HuxModuleHandler->alter()
#6 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs/src/Plugin/Field/FieldWidget/ParagraphsWidget.php(1503): Drupal\Core\Field\WidgetBase->form()
#7 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Entity/Entity/EntityFormDisplay.php(190): Drupal\paragraphs\Plugin\Field\FieldWidget\ParagraphsWidget->form()
#8 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Entity/ContentEntityForm.php(121): Drupal\Core\Entity\Entity\EntityFormDisplay->buildForm()
#9 /home/andi/git/site-h4d-greenopolis/web/core/modules/node/src/NodeForm.php(134): Drupal\Core\Entity\ContentEntityForm->form()
#10 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Entity/EntityForm.php(107): Drupal\node\NodeForm->form()
#11 [internal function]: Drupal\Core\Entity\EntityForm->buildForm()
#12 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Form/FormBuilder.php(536): call_user_func_array()
#13 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Form/FormBuilder.php(375): Drupal\Core\Form\FormBuilder->retrieveForm()
#14 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Form/FormBuilder.php(633): Drupal\Core\Form\FormBuilder->rebuildForm()
#15 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Form/FormBuilder.php(326): Drupal\Core\Form\FormBuilder->processForm()
#16 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Entity/EntityFormBuilder.php(48): Drupal\Core\Form\FormBuilder->buildForm()
#17 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/group/src/Entity/Controller/GroupRelationshipController.php(391): Drupal\Core\Entity\EntityFormBuilder->getForm()
#18 /home/andi/git/site-h4d-greenopolis/web/modules/custom/route_controller/src/WrapExistingRoute/WrapExistingRouteController.php(96): Drupal\group\Entity\Controller\GroupRelationshipController->createForm()
#19 /home/andi/git/site-h4d-greenopolis/web/modules/custom/h4d_entity_logic/src/RouteDecorator/GroupOnlyOneRouteControllerDecorator.php(66): Drupal\route_controller\WrapExistingRoute\WrapExistingRouteController->build()
#20 [internal function]: Drupal\h4d_entity_logic\RouteDecorator\GroupOnlyOneRouteControllerDecorator->build()
#21 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array()
#22 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Render/Renderer.php(638): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#23 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(121): Drupal\Core\Render\Renderer->executeInRenderContext()
#24 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext()
#25 /home/andi/git/site-h4d-greenopolis/vendor/symfony/http-kernel/HttpKernel.php(181): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#26 /home/andi/git/site-h4d-greenopolis/vendor/symfony/http-kernel/HttpKernel.php(76): Symfony\Component\HttpKernel\HttpKernel->handleRaw()
#27 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/Session.php(53): Symfony\Component\HttpKernel\HttpKernel->handle()
#28 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle()
#29 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/ContentLength.php(28): Drupal\Core\StackMiddleware\KernelPreHandle->handle()
#30 /home/andi/git/site-h4d-greenopolis/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\ContentLength->handle()
#31 /home/andi/git/site-h4d-greenopolis/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass()
#32 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Drupal\page_cache\StackMiddleware\PageCache->handle()
#33 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle()
#34 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php(36): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle()
#35 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/StackedHttpKernel.php(51): Drupal\Core\StackMiddleware\AjaxPageState->handle()
#36 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/DrupalKernel.php(741): Drupal\Core\StackMiddleware\StackedHttpKernel->handle()
#37 /home/andi/git/site-h4d-greenopolis/web/index.php(19): Drupal\Core\DrupalKernel->handle()
#38 /home/andi/git/site-h4d-greenopolis/vendor/drush/drush/misc/d8-rs-router.php(48): require('...')
#39 {main}

TypeError: _paragraphs_limits_add_more_is_empty(): Argument #1 ($element) must be of type array, null given, called in /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs_limits/paragraphs_limits.module on line 90 in _paragraphs_limits_add_more_is_empty() (line 105 of /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs_limits/paragraphs_limits.module).
Severity	Error
Hostname	127.0.0.1
Operations	
Backtrace	
#0 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs_limits/paragraphs_limits.module(90): _paragraphs_limits_add_more_is_empty()
#1 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs_limits/paragraphs_limits.module(45): _paragraphs_limits_disallow_limited_paragraphs()
#2 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Extension/ModuleHandler.php(552): paragraphs_limits_field_widget_complete_paragraphs_form_alter()
#3 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/hux/src/HuxModuleHandler.php(163): Drupal\Core\Extension\ModuleHandler->alter()
#4 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Field/WidgetBase.php(156): Drupal\hux\HuxModuleHandler->alter()
#5 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/paragraphs/src/Plugin/Field/FieldWidget/ParagraphsWidget.php(1503): Drupal\Core\Field\WidgetBase->form()
#6 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Entity/Entity/EntityFormDisplay.php(190): Drupal\paragraphs\Plugin\Field\FieldWidget\ParagraphsWidget->form()
#7 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Entity/ContentEntityForm.php(121): Drupal\Core\Entity\Entity\EntityFormDisplay->buildForm()
#8 /home/andi/git/site-h4d-greenopolis/web/core/modules/node/src/NodeForm.php(134): Drupal\Core\Entity\ContentEntityForm->form()
#9 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Entity/EntityForm.php(107): Drupal\node\NodeForm->form()
#10 [internal function]: Drupal\Core\Entity\EntityForm->buildForm()
#11 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Form/FormBuilder.php(536): call_user_func_array()
#12 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Form/FormBuilder.php(375): Drupal\Core\Form\FormBuilder->retrieveForm()
#13 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Form/FormBuilder.php(633): Drupal\Core\Form\FormBuilder->rebuildForm()
#14 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Form/FormBuilder.php(326): Drupal\Core\Form\FormBuilder->processForm()
#15 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Entity/EntityFormBuilder.php(48): Drupal\Core\Form\FormBuilder->buildForm()
#16 /home/andi/git/site-h4d-greenopolis/web/modules/contrib/group/src/Entity/Controller/GroupRelationshipController.php(391): Drupal\Core\Entity\EntityFormBuilder->getForm()
#17 /home/andi/git/site-h4d-greenopolis/web/modules/custom/route_controller/src/WrapExistingRoute/WrapExistingRouteController.php(96): Drupal\group\Entity\Controller\GroupRelationshipController->createForm()
#18 /home/andi/git/site-h4d-greenopolis/web/modules/custom/h4d_entity_logic/src/RouteDecorator/GroupOnlyOneRouteControllerDecorator.php(66): Drupal\route_controller\WrapExistingRoute\WrapExistingRouteController->build()
#19 [internal function]: Drupal\h4d_entity_logic\RouteDecorator\GroupOnlyOneRouteControllerDecorator->build()
#20 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array()
#21 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/Render/Renderer.php(638): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#22 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(121): Drupal\Core\Render\Renderer->executeInRenderContext()
#23 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext()
#24 /home/andi/git/site-h4d-greenopolis/vendor/symfony/http-kernel/HttpKernel.php(181): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#25 /home/andi/git/site-h4d-greenopolis/vendor/symfony/http-kernel/HttpKernel.php(76): Symfony\Component\HttpKernel\HttpKernel->handleRaw()
#26 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/Session.php(53): Symfony\Component\HttpKernel\HttpKernel->handle()
#27 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle()
#28 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/ContentLength.php(28): Drupal\Core\StackMiddleware\KernelPreHandle->handle()
#29 /home/andi/git/site-h4d-greenopolis/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\ContentLength->handle()
#30 /home/andi/git/site-h4d-greenopolis/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass()
#31 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Drupal\page_cache\StackMiddleware\PageCache->handle()
#32 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle()
#33 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php(36): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle()
#34 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/StackMiddleware/StackedHttpKernel.php(51): Drupal\Core\StackMiddleware\AjaxPageState->handle()
#35 /home/andi/git/site-h4d-greenopolis/web/core/lib/Drupal/Core/DrupalKernel.php(741): Drupal\Core\StackMiddleware\StackedHttpKernel->handle()
#36 /home/andi/git/site-h4d-greenopolis/web/index.php(19): Drupal\Core\DrupalKernel->handle()
#37 /home/andi/git/site-h4d-greenopolis/vendor/drush/drush/misc/d8-rs-router.php(48): require('...')
#38 {main}

So the issue seems to be happening when the field is limited by core's field storage setting "Allowed number of values". If this is set to unlimited the pages are working as intended. If this is limited at the storage level, Drupal removes the add more button completely from the form and paragraphs_limits breaks.

Would be nice to have a test for this.

Admittedly setting a limit at the storage level was not something I thought about since I thought we'd be setting granular limits using the handler. Good catch!

Is it fair to assume that you weren't using the patch from ✨ This module should disallow adding more than the allowed amount of paragraph items in the add widget Fixed prior to rc2?

@pavlosdan Thanks for your reply! That's correct ;)

Indeed, when setting field storage to unlimited this issue does not come up. I can see edge cases that might want to use limited storage, but we don't have them atm.

Tests for storage limit added.

Merged. Thanks all!

Automatically closed - issue fixed for 2 weeks with no activity.