Spring Support suspending handler methods in Spring MVC

Following Coroutines support introduced in Spring WebFlux and since Spring MVC supports Mono via the ReactiveAdapterRegistry, it would probably makes sense to support Coroutines (suspending handler methods) in Spring MVC.

It will require similar handling than in WebFlux side + disabling the check introduced via #23585.

Good candidate for Spring Framework 5.3.

Comment From: achatellier

Hello Sebastien, I have seen your conference at Bordeaux this week (thanks for that, I learned a lot) and I was trying to use suspending handler methods.

Is there a way to test it today with a Spring beta version (I can't find one) or do I have to wait for the 5.3 release to use this feature ?

I've made a test with Spring 5.2 and obviously it doesn't work. (Sorry if it's not the right place to ask this question)

Comment From: sdeleuze

Hi, such support is not yet available in snapshots so you have to wait or contribute a PR ;-)

Comment From: sgarfinkel

@sdeleuze Is this still unimplemented? This article clearly implies that WebMVC supports suspendible functions: https://spring.io/blog/2019/04/12/going-reactive-with-spring-coroutines-and-kotlin-flow

I think this limitation should be more clearly documented.

Comment From: sdeleuze

@sgarfinkel I don't think this article I have written imply that. Coroutines section specifies are supported only in WebFlux for now.