[kotlin-spring] Handle arrays of files correctly using MultipartFile

[ffffionn]

This handles request parameters of arrays of files correctly, as well as changing them to use Spring's Multipart File class, as is recommended. Previously, Spring's Resource would be used as the input and the Delegate class would not recognize the array

Fixes the following open issues for Kotlin-spring generator:
#8333
#15251

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[ffffionn]

I'm not sure that I did the samples properly, as they seem to have switched to Windows path separators instead.
I used Git Bash on Windows

[wing328]

thanks for the PR. i've filed #20117 with updated samples.

is it correct to say that this is a breaking change as org.springframework.web.multipart.MultipartFile is used instead?

[ffffionn]

@wing328 Yeah, I guess you could consider it that. All Spring documentation says to be using MultipartFile for uploads (but we still keep Resource for downloads)

[wing328]

can you please review the build failure when you've time?

https://github.com/OpenAPITools/openapi-generator/actions/runs/11868985076/job/33078813658?pr=20117

[wing328]

@wing328 Yeah, I guess you could consider it that. All Spring documentation says to be using MultipartFile for uploads (but we still keep Resource for downloads)

ok. i'll see if i can come up with a way to fallback in case the users prefer the current implementation.

[ffffionn]

can you please review the build failure when you've time?

https://github.com/OpenAPITools/openapi-generator/actions/runs/11868985076/job/33078813658?pr=20117

Sorry, I'm a bit of a noob on Github Actions. Maven build passes successfully when run, is there a way to run these tests locally? (should they be included in mvn test?)

[wing328]

can you run ./gradlew build -x test in samples/server/petstore/kotlin-springboot-source-swagger1 for example?

[ffffionn]

There isn't any gradle wrapper in that directory

EDIT: Ah I got it to run locally after some playing around. Let me fix these issues..
(This would be ideally solved with being able to set the typeMapping for file differently on input parameters vs response type - but in the absence of this, the solution to hard-code the MultipartFile type will do)

[ffffionn]

@wing328 I made some changes but there doesn't seem to be a good way to verify all the samples compile. I feel like this should be part of the maven build

[wing328]

fyi. updated samples via 2c25491

[wing328]

agreed with you that we should also test the kotlin spring project with maven as well

[wing328]

cc @dr4ke616 (2018/08) @karismann (2019/03) @Zomzog (2019/04) @andrewemery (2019/10) @4brunu (2019/11) @yutaka0m (2020/03) @stefankoppier (2022/06) @e5l (2024/10)