Add @ControllerAdvice support to RSocket messaging auto-configuration

[dmitrysulman]

This PR adds support for beans annotated with @ControllerAdvice inRSocketMessagingAutoConfiguration, allowing the use of global @MessageExceptionHandler methods.

See spring-projects/spring-framework#26636 (comment)

Fixes #45360

[snicoll]

Thanks for the PR! Closed by b10262c (I used the id of the linked issue).

@ControllerAdvice and ControllerAdviceBean are in spring-web unfortunately and spring-messaging cannot depend on that.

FTR neither can we, so my polish commit moves that to a separate customizer that only kicks in if spring-web is also on the classpath.

[dmitrysulman]

@snicoll thanks!

FTR neither can we

I just wanted to clarify. Currently spring-web is declared as an implementation dependency in the spring-boot-rsocket module (see its build.gradle), so it's always on the classpath. Should this actually be an optional dependency instead?

[snicoll]

Currently spring-web is declared as an implementation dependency in the spring-boot-rsocket module

Good point I had missed that. I think that's worth exploring. See #47409 for further details.