Hi cilefen,
I tried reverting to the regex expression before the change from #3446381, but I still get the same behavior. In the version of Drupal were upgrading from, 10.2.7, the class was still part of the SDC module. We do have a folder named components in our theme directory so this may very well be related to that issue.
It looks like in the working version, the \Drupal\Core\Plugin\Discovery\DirectoryWithMetadataPluginDiscovery class was never called at all in the previous version, thus no issue. One of the changes must have triggered this class to now be used for discovery so there must be more going on.
Here is the stack trace I'm dealing with:
Drupal\Core\Render\Component\Exception\InvalidComponentException: Unable to find the Twig template for the component "compony:select". in Drupal\Core\Plugin\Component->__construct() (line 58 of core/lib/Drupal/Core/Plugin/Component.php).
Drupal\Core\Plugin\Factory\ContainerFactory->createInstance() (Line: 83)
Drupal\Component\Plugin\PluginManagerBase->createInstance() (Line: 102)
Drupal\Core\Theme\ComponentPluginManager->createInstance()
array_map() (Line: 150)
Drupal\Core\Theme\ComponentPluginManager->getAllComponents() (Line: 488)
Drupal\Core\Asset\LibraryDiscoveryParser->librariesForComponents() (Line: 409)
Drupal\Core\Asset\LibraryDiscoveryParser->parseLibraryInfo() (Line: 157)
Drupal\Core\Asset\LibraryDiscoveryParser->buildByExtension() (Line: 87)
Drupal\Core\Asset\LibraryDiscoveryCollector->getLibraryDefinitions() (Line: 66)
Drupal\Core\Asset\LibraryDiscoveryCollector->resolveCacheMiss() (Line: 149)
Drupal\Core\Cache\CacheCollector->get() (Line: 44)
Drupal\Core\Asset\LibraryDiscovery->getLibrariesByExtension() (Line: 58)
Drupal\Core\Asset\LibraryDiscovery->getLibraryByName() (Line: 68)
Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies() (Line: 70)
Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies() (Line: 41)
Drupal\Core\Asset\LibraryDependencyResolver->getLibrariesWithDependencies() (Line: 87)
Drupal\Core\Asset\LibraryDependencyResolver->getMinimalRepresentativeSubset() (Line: 113)
Drupal\Core\Asset\AssetResolver->getLibrariesToLoad() (Line: 128)
Drupal\Core\Asset\AssetResolver->getCssAssets() (Line: 323)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries() (Line: 167)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments() (Line: 97)
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: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass() (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 53)
Asm89\Stack\Cors->handle() (Line: 263)
Drupal\shield\ShieldMiddleware->bypass() (Line: 219)
Drupal\shield\ShieldMiddleware->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 124)
Drupal\cloudflare\CloudFlareMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 741)
Drupal\Core\DrupalKernel->handle() (Line: 19)
Thank you for bringing this to my attention, tgoeg.
It looks like an unexpected compatibility issue with Symfony 4, so I have changed the version requirement to Drupal 10 and above which runs on Symfony 6.
Sorry for the trouble.