Error message

• Warning: Undefined variable $level in Drupal\herneeds_product_details\Plugin\Field\FieldFormatter\CustomStockLevelFormatter->viewElements() (line 95 of modules/custom/herneeds_product_details/src/Plugin/Field/FieldFormatter/CustomStockLevelFormatter.php).

  Drupal\herneeds_product_details\Plugin\Field\FieldFormatter\CustomStockLevelFormatter->viewElements() (Line: 91)
  Drupal\Core\Field\FormatterBase->view() (Line: 268)
  Drupal\Core\Entity\Entity\EntityViewDisplay->buildMultiple() (Line: 340)
  Drupal\Core\Entity\EntityViewBuilder->buildComponents() (Line: 282)
  Drupal\Core\Entity\EntityViewBuilder->buildMultiple() (Line: 239)
  Drupal\Core\Entity\EntityViewBuilder->build()
  call_user_func() (Line: 37)
  Drupal\commerce_product\ProductVariationFieldRenderer->renderFields() (Line: 96)
  Drupal\commerce_product\ProductViewBuilder->alterBuild() (Line: 292)
  Drupal\Core\Entity\EntityViewBuilder->buildMultiple() (Line: 239)
  Drupal\Core\Entity\EntityViewBuilder->build()
  call_user_func_array() (Line: 113)
  Drupal\Core\Render\Renderer->doTrustedCallback() (Line: 870)
  Drupal\Core\Render\Renderer->doCallback() (Line: 432)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 238)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 638)
  Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 231)
  Drupal\Core\Render\MainContent\HtmlRenderer->prepare() (Line: 128)
  Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse() (Line: 90)
  Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray()
  call_user_func() (Line: 111)
  Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch() (Line: 186)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
  Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 32)
  Drupal\big_pipe\StackMiddleware\ContentLength->handle() (Line: 191)
  Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 128)
  Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 82)
  Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
  Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 741)
  Drupal\Core\DrupalKernel->handle() (Line: 19)
  

• Notice: Only variables should be passed by reference in herneeds_product_details_form_commerce_order_item_add_to_cart_form_alter() (line 56 of modules/custom/herneeds_product_details/herneeds_product_details.module).

  herneeds_product_details_form_commerce_order_item_add_to_cart_form_alter() (Line: 552)
  Drupal\Core\Extension\ModuleHandler->alter() (Line: 834)
  Drupal\Core\Form\FormBuilder->prepareForm() (Line: 285)
  Drupal\Core\Form\FormBuilder->buildForm() (Line: 97)
  Drupal\commerce_product\ProductLazyBuilders->addToCartForm()
  call_user_func_array() (Line: 113)
  Drupal\Core\Render\Renderer->doTrustedCallback() (Line: 870)
  Drupal\Core\Render\Renderer->doCallback() (Line: 411)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 165)
  Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}() (Line: 638)
  Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 164)
  Drupal\Core\Render\Renderer->renderInIsolation() (Line: 191)
  Drupal\Core\Render\Renderer->doRenderPlaceholder() (Line: 723)
  Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}()
  Fiber->start() (Line: 731)
  Drupal\Core\Render\Renderer->replacePlaceholders() (Line: 608)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 153)
  Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}() (Line: 638)
  Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 152)
  Drupal\Core\Render\Renderer->renderRoot() (Line: 288)
  Drupal\Core\Render\HtmlResponseAttachmentsProcessor->renderPlaceholders() (Line: 74)
  Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments() (Line: 45)
  Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond()
  call_user_func() (Line: 111)
  Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch() (Line: 214)
  Symfony\Component\HttpKernel\HttpKernel->filterResponse() (Line: 202)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
  Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 32)
  Drupal\big_pipe\StackMiddleware\ContentLength->handle() (Line: 191)
  Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 128)
  Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 82)
  Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
  Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 741)
  Drupal\Core\DrupalKernel->handle() (Line: 19)