PHP 8.1 compatibility

I think this is a mistake in the definition of a library.

The "component" key does not have an S at the end.

base:
  css:
    component: <---
      css/components/foo.css:

This only happens when ipless module is enabled. Site opens normal if module is disabled.

I saw only one similar post about this and it was about the componen(s): definition here as you suggested .

But inside drupal (9) there are lots of modules still using component: instead of components:

Below is the full error message I found.

Error: Undefined constant "CSS_COMPONENTS" in constant() (line 180 of /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscoveryParser.php)
#0 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscoveryParser.php(180): constant()
#1 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscoveryCollector.php(87): Drupal\Core\Asset\LibraryDiscoveryParser->buildByExtension()
#2 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscoveryCollector.php(66): Drupal\Core\Asset\LibraryDiscoveryCollector->getLibraryDefinitions()
#3 /var/www/uydu/web/core/lib/Drupal/Core/Cache/CacheCollector.php(149): Drupal\Core\Asset\LibraryDiscoveryCollector->resolveCacheMiss()
#4 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscoveryCollector.php(149): Drupal\Core\Cache\CacheCollector->get()
#5 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscoveryCollector.php(111): Drupal\Core\Asset\LibraryDiscoveryCollector->applyLibrariesExtend()
#6 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscoveryCollector.php(66): Drupal\Core\Asset\LibraryDiscoveryCollector->getLibraryDefinitions()
#7 /var/www/uydu/web/core/lib/Drupal/Core/Cache/CacheCollector.php(149): Drupal\Core\Asset\LibraryDiscoveryCollector->resolveCacheMiss()
#8 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscovery.php(44): Drupal\Core\Cache\CacheCollector->get()
#9 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDiscovery.php(58): Drupal\Core\Asset\LibraryDiscovery->getLibrariesByExtension()
#10 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDependencyResolver.php(68): Drupal\Core\Asset\LibraryDiscovery->getLibraryByName()
#11 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDependencyResolver.php(70): Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies()
#12 /var/www/uydu/web/core/lib/Drupal/Core/Asset/LibraryDependencyResolver.php(41): Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies()
#13 /var/www/uydu/web/core/lib/Drupal/Core/Asset/AssetResolver.php(104): Drupal\Core\Asset\LibraryDependencyResolver->getLibrariesWithDependencies()
#14 /var/www/uydu/web/core/lib/Drupal/Core/Asset/AssetResolver.php(116): Drupal\Core\Asset\AssetResolver->getLibrariesToLoad()
#15 /var/www/uydu/web/core/lib/Drupal/Core/Render/HtmlResponseAttachmentsProcessor.php(312): Drupal\Core\Asset\AssetResolver->getCssAssets()
#16 /var/www/uydu/web/core/lib/Drupal/Core/Render/HtmlResponseAttachmentsProcessor.php(158): Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries()
#17 /var/www/uydu/web/core/modules/big_pipe/src/Render/BigPipeResponseAttachmentsProcessor.php(94): Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments()
#18 /var/www/uydu/web/core/lib/Drupal/Core/EventSubscriber/HtmlResponseSubscriber.php(45): Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments()
#19 [internal function]: Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond()
#20 /var/www/uydu/web/core/lib/Drupal/Component/EventDispatcher/ContainerAwareEventDispatcher.php(142): call_user_func()
#21 /var/www/uydu/vendor/symfony/http-kernel/HttpKernel.php(202): Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch()
#22 /var/www/uydu/vendor/symfony/http-kernel/HttpKernel.php(190): Symfony\Component\HttpKernel\HttpKernel->filterResponse()
#23 /var/www/uydu/vendor/symfony/http-kernel/HttpKernel.php(81): Symfony\Component\HttpKernel\HttpKernel->handleRaw()
#24 /var/www/uydu/web/core/lib/Drupal/Core/StackMiddleware/Session.php(58): Symfony\Component\HttpKernel\HttpKernel->handle()
#25 /var/www/uydu/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle()
#26 /var/www/uydu/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\KernelPreHandle->handle()
#27 /var/www/uydu/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass()
#28 /var/www/uydu/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Drupal\page_cache\StackMiddleware\PageCache->handle()
#29 /var/www/uydu/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle()
#30 /var/www/uydu/web/modules/contrib/remove_http_headers/src/StackMiddleware/RemoveHttpHeadersMiddleware.php(49): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle()
#31 /var/www/uydu/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\remove_http_headers\StackMiddleware\RemoveHttpHeadersMiddleware->handle()
#32 /var/www/uydu/web/core/lib/Drupal/Core/DrupalKernel.php(713): Stack\StackedHttpKernel->handle()
#33 /var/www/uydu/web/index.php(19): Drupal\Core\DrupalKernel->handle()
#34 {main}

Also a side note; On my other 8.1 server I use drupal10 and everything works fine with ipless. Not sure if this will be helpfull :)

All possible groups are :

• base
• layout
• component
• state
• theme

In your case, you have a library with "components" group key.
If your site is working fine with ipless disabled, it means that you have a library like this one:

base:
  less:
    components: <---
      css/components/foo.css:

You can try something like this and you'll get the same error:

base:
  css:
    foo: <---
      css/components/foo.css:

'Error: Undefined constant "CSS_FOO" in constant() (line 180 of

This is not an error of the module, but an error in a lbrary.