[JAVA] [SPRING] Handle list of String special case in reactive generator

[TMRGZ]

Related: #24077

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Summary by cubic

Fixes reactive Spring return types for string[] responses by returning Mono<List> or Mono<Set> instead of Flux. Applies to spring-boot and spring-http-interface, including SSE, and aligns generated code with the schema.

• Bug Fixes
  • Added x-reactive-return-except-list-of-string to VendorExtension.
  • In SpringCodegen, auto-set the extension for reactive string[] returns in spring-boot and spring-http-interface.
  • Updated responseType.mustache to emit Mono<ResponseEntity<List<String>>>/Mono<ResponseEntity<Set<String>>> (or Mono<List<String>>/Mono<Set<String>> when useResponseEntity is false), including SSE.
  • Added tests for both libraries with useResponseEntity on/off to verify the new signatures.

^{Written for commit f4784ea. Summary will update on new commits.}

[TMRGZ]

The Kotlin Spring generator could need a similar fix but I am not used to code in Kotlin, feel free to add it to this PR

[Picazsoo]

I only reviewed on mobile so far, but do I understand correctly that you are hiding the 'now correct' behavior behind a config option and by default it will still produce the incorrect code?

I would expect it to be either

• a) just a straightforward fix with no fallback. If someone depends on the wrong behavior, they should go and fix their code. They will be probably forced to anyway as the code will not compile after upgrading...
• b) inverted behavior - default to the fix and allow custom config to get the 'wrong' behavior back.

As I mentioned this is based on a very quick skimming of the changes in the PR.

Note: I am not in any way a maintainer of this project - just providing my proverbial 2 cents of feedback (-:

[TMRGZ]

Hi @Picazsoo, thanks for the feedback.

Just to note, the feature flag for the fix is enabled by default and the PR is and adaptation of this other https://github.com/OpenAPITools/openapi-generator/pull/16326/changes.

I guess that the fallback was created just in case someone wants to stay with the original behaviour.

[Picazsoo]

If no one picks it up for kotlin-spring before next week, I will see what I can do. I think that reactor is limited to spring http interface there...

[cubic-dev-ai]

1 issue found across 4 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>