Replace hook_requirements with tagged services

Maybe it could use attribute based discovery instead?

Hmm. Having a look at 🌱 [META] Hooks via attributes on service methods (hux style) Active this way more complex that I imagined.

@larowlan pointed out in slack that 'install' checks for hook_requirements run _before_ a module is enabled/loaded, so we can't use services for this.

Yes, there's no services before installing but composer namespaces are setup-up so discovery is possible

Related 📌 Deprecate drupal_check_module() and replace with a service Needs review

Hmm. I guess we could something like:

$requirements = $classResolver->getInstanceFromDefinition("\Drupal\{$module}\Requirements");

That way classes implementing ContainerInjectionInterface could have other non-module services injected.

I wonder how attributes would help?

Not sure whether this is worth pursuing or not. 🤔

Would you mind my adding this as part of Follow up 3? 📌 [PP-1] Explore converting Install hooks to OOP Active

There are actually two parts to hook requirements, there is a hook requirements for runtime that can be OOP and hook_requirements during install which likely cannot be converted.