[REQ][kotlin-spring] Add possibility to turn off Flow usage when reactive=true

[hu553in]

Is your feature request related to a problem? Please describe.

We want to use suspend functions for methods returning single objects, but also we want to use common return types (e.g. List) for methods returning collections.

Our UI can not work with JSON streams at the moment.

On Spring 5 Flow was collected to List internally when Content-Type is application/json, but in Spring 6 this functionality is removed, so we need to return List explicitly.

Describe the solution you'd like

Some option like useFlowForArrayReturnType which will turn on/off using Flow. Possibly it should be considered only if reactive is set to true.

[jeferro]

+1

[sekaninovam]

+1

[wing328]

If anyone would like to contribute or sponsor a PR for this enhancement, please reply to let us know. Thank you.

[hu553in]

@wing328 I took it, will try to implement

[hu553in]

@wing328 hello. Actually I fucked up a bit. The point is that collection endpoints were generated without suspend modified due to their Flow usage and possibility to call suspend methods when building flow. But now, when I added this feature and now can turn off Flow usage, we continue to generate collection endpoints without suspend modifier, and now I can't call any suspend functions from them even if all my backend code is reactive. I think I need to make changes. If reactive=true and my option is turned off, then need to add suspend modifier to collection endpoints as well 🤔

[hu553in]

@wing328 hello, could you check this please? And please check previous comment. Excuse me for this :)