Well, this method is not a supported extension point currently. I'm not sure we want to make it a supported inheritance extension point for people extending our cache implementations

and anyway, doing it in 3.3 is a no-go. Adding new inheritance-based extension point is considered a new feature.

I agree with@stof
Incrementing the namespace is not a supported strategy because it requires a backend round-trip to fetch its current version.
Instead, just change the namespace.

$namespace is also private and there is no setter.

I can achieve the same result by extending all the protected methods and changing the id there, but since there is already getId-method that seems a bit bulky.

So, you need instant clearing? Did you measure it as slow on your use case? By how much?

I want to clear a namespaced memcached instance and I expect all other memcached instances not to be cleared afterwards.
Memcached does not support clearing by prefix or regex like APC or Redis.
And for clearing a namespaced cache, incrementing the namespace is good solution.

OK, got it. I suggest considering the issue as a bug, and implementing this strategy in the existing MemcachedTrait: when a non empty namespace is used, we do versioning. The extra round trip is the only way to solve the issue anyway.

Thank you for raising the point@hcomnetworkers
I implemented by-versioning clearing in#23969 as an option for drivers (since RedisCluster also had a similar issue).
I'd be happy to have your review on that PR.
Closing this PR meanwhile. Thanks again.