Symfony version(s) affected

5.3.x, probably earlier

Description

Framework-provided cache pools take priority over those defined in the cache config by user, and do so without warning.

How to reproduce

While setting up the rate limiter, I saw that it uses the cache.rate_limiter pool by default. This pool extends the cache.app one as per

I wanted to make sure all rate limiters get stored somewhere else than the app cache, so it seemed obvious to me that I could redefine the cache.rate_limiter pool in the config and get this to be written somewhere else:

framework:
    cache:
        # [...]
        pools:
            cache.rate_limiter:
                adapter: cache.adapter.redis
                provider: '%redis_rate_limiter_dsn%'

Then a few months later I now realize this does not work at all. It seems like the service definition in FrameworkBundle/rate_limiter.php overwrites my cache pool silently, and so everything is still dumped in the app cache.

Possible Solution

A few alternatives I see to improve things:

1. The best solution to me would be that if a pool is defined already then FrameworkBundle would not recreate that service.
2. If redefining framework pools is frowned upon, then maybe the reserved list could be expanded a bit to include other cache.x pools.

Additional Context

No response