Discount codes for events, PHP 8.1 and Drupal 9 error
On a PHP 8.1 system / Drupal 9, using events, the following error occurs. With no option to continue;
TypeError: count(): Argument #1 ($value) must be of type Countable|array, null given in include() (line 7 of /home/web/sites/default/files/civicrm/templates_c/en_GB/%%2F/2F3/2F376CCE%%BillingBlock.tpl.php) #0 /home/vendor/civicrm/civicrm-packages/Smarty/Smarty.class.php(1915): include() #1 /home/web/sites/default/files/civicrm/templates_c/en_GB/%%C2/C29/C29BF079%%BillingBlockWrapper.tpl.php(8): Smarty->_smarty_include(Array) #2 /home/vendor/civicrm/civicrm-packages/Smarty/Smarty.class.php(1915): include('/home/st...') #3 (closed) /home/web/sites/default/files/civicrm/templates_c/en_GB/%%4F/4FB/4FBAC7AC%%Register.tpl.php(174): Smarty->_smarty_include(Array) #4 (closed) /home/vendor/civicrm/civicrm-packages/Smarty/Smarty.class.php(1915): include('/home/st...') #5 /home/web/sites/default/files/civicrm/templates_c/en_GB/%%0C/0CB/0CBEC124%%default.tpl.php(19): Smarty->_smarty_include(Array) #6 /home/vendor/civicrm/civicrm-packages/Smarty/Smarty.class.php(1915): include('/home/st...') #7 /home/web/sites/default/files/civicrm/templates_c/en_GB/%%F7/F77/F77C7890%%CMSPrint.tpl.php(61): Smarty->_smarty_include(Array) #8 /home/vendor/civicrm/civicrm-packages/Smarty/Smarty.class.php(1915): include('/home/st...') #9 /home/web/sites/default/files/civicrm/templates_c/en_GB/%%2B/2BD/2BD99720%%drupal8.tpl.php(6): Smarty->_smarty_include(Array) #10 (closed) /home/vendor/civicrm/civicrm-packages/Smarty/Smarty.class.php(1274): include('/home/st...') #11 (closed) /home/vendor/civicrm/civicrm-core/CRM/Core/Smarty.php(189): Smarty->fetch('CRM/common/drup...', NULL, NULL, false) #12 (closed) /home/vendor/civicrm/civicrm-core/CRM/Core/QuickForm/Action/Display.php(117): CRM_Core_Smarty->fetch('CRM/common/drup...') #13 (closed) /home/vendor/civicrm/civicrm-core/CRM/Core/QuickForm/Action/Display.php(83): CRM_Core_QuickForm_Action_Display->renderForm(Object(CRM_Event_Form_Registration_Register)) #14 /home/vendor/civicrm/civicrm-packages/HTML/QuickForm/Controller.php(203): CRM_Core_QuickForm_Action_Display->perform(Object(CRM_Event_Form_Registration_Register), 'display') #15 /home/vendor/civicrm/civicrm-packages/HTML/QuickForm/Page.php(103): HTML_QuickForm_Controller->handle(Object(CRM_Event_Form_Registration_Register), 'display') #16 /home/vendor/civicrm/civicrm-core/CRM/Core/QuickForm/Action/Reload.php(53): HTML_QuickForm_Page->handle('display') #17 /home/vendor/civicrm/civicrm-packages/HTML/QuickForm/Controller.php(203): CRM_Core_QuickForm_Action_Reload->perform(Object(CRM_Event_Form_Registration_Register), 'reload') #18 /home/vendor/civicrm/civicrm-packages/HTML/QuickForm/Page.php(103): HTML_QuickForm_Controller->handle(Object(CRM_Event_Form_Registration_Register), 'reload') #19 /home/vendor/civicrm/civicrm-core/CRM/Core/Controller.php(355): HTML_QuickForm_Page->handle('reload') #20 /home/vendor/civicrm/civicrm-core/CRM/Core/Invoke.php(319): CRM_Core_Controller->run(Array, NULL) #21 /home/vendor/civicrm/civicrm-core/CRM/Core/Invoke.php(69): CRM_Core_Invoke::runItem(Array) #22 /home/vendor/civicrm/civicrm-core/CRM/Core/Invoke.php(36): CRM_Core_Invoke::_invoke(Array) #23 (closed) /home/web/modules/contrib/civicrm/src/Civicrm.php(88): CRM_Core_Invoke::invoke(Array) #24 (closed) /home/web/modules/contrib/civicrm/src/Controller/CivicrmController.php(80): Drupal\civicrm\Civicrm->invoke(Array) #25 [internal function]: Drupal\civicrm\Controller\CivicrmController->main(Array, '') #26 /home/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array) #27 (closed) /home/web/core/lib/Drupal/Core/Render/Renderer.php(580): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber{closure}() #28 /home/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #29 /home/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) #30 /home/vendor/symfony/http-kernel/HttpKernel.php(169): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber{closure}() #31 /home/vendor/symfony/http-kernel/HttpKernel.php(81): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #32 (closed) /home/web/core/lib/Drupal/Core/StackMiddleware/Session.php(58): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #33 /home/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #34 /home/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #35 (closed) /home/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #36 /home/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #37 (closed) /home/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #38 (closed) /home/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #39 (closed) /home/web/core/lib/Drupal/Core/DrupalKernel.php(718): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #40 /home/web/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #41 (closed) {main}