Reverting #45476 will break streamedresponses for other Runtimes like Roadrunner, Swoole (php-runtime/runtime#115), is there any possibility todo this only when specific Runtime is used? /cc @nicolas-grekas.

Addition: The problem also is that it would behave differently between Roadrunner, Swoole, now as they could then still run into #46743 where this listener is required to be disabled. I understand @derrabus concern about #51139 but to have full support for such runtimes I don't see another way then make HttpKernel aware of a Response class specially it already has dependency to HttpFoundation.

Thanks for the reminder @alexander-schranz

I understand @derrabus concern about #51139 but to have full support for such runtimes I don't see another way then make HttpKernel aware of a Response class specially it already has dependency to HttpFoundation.

The other way would be to document that the request stack is empty when StreamedResponse's callback is executed. This is fine imho.

Note that the breaking change was to un-wire the deprecated listener which has happened without prior deprecation in a minor release. We could wire it again, but make it opt-out by introducing a config flag into FrameworkBundle. Yeah, I know how we don't like those.

document that the request stack is empty when StreamedResponse's callback is executed

This ship has sailed IMHO. Also it's very hard to deal with, because any services can be used in that callback. I think #51396 is pragmatic and makes sense also.

I think #51396 is pragmatic and makes sense also.

LGTM.