Detect other PSR violations where namespace is missing or not a subnamespace of configured one

[PrinsFrank]

Fixes composer/composer#11957

To get warnings about missing namespaces or non-common namespaces in Composer when running with --strict-psr, classes shouldn't be skipped before checking their namespace if they don't have a common root.

[szepeviktor]

No silent ignoring 👍🏻

[Seldaek]

Thanks, I think it makes sense but I am a bit worried about unforeseen side-effects here.. It should only be warnings though nothing dramatic so let's merge and see if we get more feedback than expected :)

[Seldaek]

@PrinsFrank already got a bunch of errors on the Composer repo due to test fixtures😅

One last one I cannot fix immediately tho is in a dependency:

Class SymfonyExcludeListSimplePhpunit located in ./vendor/symfony/phpunit-bridge/bin/simple-phpunit.php does not comply with psr-4 autoloading standard (expected namespace Symfony\Bridge\PhpUnit\). Skipping.

So my guess is it will cause more pain than we think..

[PrinsFrank]

@Seldaek these warnings only really make sense in the composer project itself, right? Errors in autoloaded classes can be more easily found if the strict-psr is run in the project itself, but if a dependency ships with non-psr4 compliant classes I don't think it makes sense to show these errors in dependant packages?

[Seldaek]

Right yes that's true. I need to see if I can ignore dependencies. It's not that easy given the API we have here.

[PrinsFrank]

I can look into this this weekend as well if you want? I'd love to help out right now, but I'm ill at the moment. ;)

[Seldaek]

Nah don't worry I am on it. 6307dcf fixes some of the problems already. And the new method added there will let me clean up vendor warnings in Composer.

Hope you get well soon!