Revisit dependency to Spring Messaging

[fmbenhassine]

Discussed in #1204

^{Originally posted by piotrooo November 1, 2025}
I'd like to ask about the rationale for using spring-messaging in spring-shell. The only reason I can see is to reuse Message and HandlerMethodArgumentResolver as some kind of generic holder (?) for multiple purposes.

Is that really the best approach? It feels a bit bizarre.

Maybe a spring-shell specific HandlerMethodArgumentResolver should be introduced, and the dependency on spring-messaging could be dropped?

[fmbenhassine]

I couldn't agree more! I came to the same conclusion when I was reviewing dependencies (similar to having core depending on a ui module, see c95651a).. Same thing for reactor dependency, I see no added value of using it in the context of interactive shell applications (even in non interactive mode BTW, with all the complexity in DefaultEventLoop).

Anyway, I will plan this for v4 and see if we can improve things with less dependencies.