[Kotlin][Client] Add option to make all api method return a nullable model

[AlexanderEggers]

Closes #4418

• added new additional-parameter nullableReturnType
  • converts the api related methods from non-null to nullable
  • change the class member data of ApiInfrastructureResponse.Success to a nullable type
• added new kotlin-client sample to show the nullable changes
• added new shell and bash script files

It probably makes sense to merge #4419 first. I will take care of any merge conflicts.

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[AlexanderEggers]

PR is ready for review.

@jimschubert (2017/09) ❤️, @dr4ke616 (2018/08) @karismann (2019/03) @Zomzog (2019/04) @andrewemery (2019/10)

[AlexanderEggers]

@wing328 Since I dragged in your PR, the circleci step is failing. Do you have an idea for how to fix that? Besides that, the PR is ready for review. I fixed the merge conflicts that were caused by your PR.

[jimschubert]

Looks like a great addition! Just had a few questions.

Should we also maybe consider adding a default of false to the generator, so it's clear in code that this is an option? I eventually want to make additionalProperties sorted by embedded templates to be discoverable.

[AlexanderEggers]

Thanks for your feedback. 👍

Should we also maybe consider adding a default of false to the generator, so it's clear in code that this is an option? I eventually want to make additionalProperties sorted by embedded templates to be discoverable.

Do you mean adding the option to this readme >> https://github.com/OpenAPITools/openapi-generator/blob/master/docs/generators/kotlin.md

[jimschubert]

@Mordag regarding the default in the generator, I was referring to something like this:

openapi-generator/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java

Line 394 in 11bcb66

if (additionalProperties.containsKey(CodegenConstants.SOURCE_FOLDER)) {

However, based on the other discussions, it looks like there won't be other changes so I can just pick up the additionalProperties thing later.

My only remaining question on the PR is related to the mediaType guard.

Let me know if you'd like help looking into the CI error. You mentioned it failing after pulling in changes, but I don't see an additional commit (so I didn't know where to begin). It seems from looking at the logs that it failed on Kotlin generation. It could be as simple as missing the executable flag on bin/kotlin-client-nullable.sh

[AlexanderEggers]

@jimschubert I removed the mediaType for now and updated the samples. If all tests are green, the PR should be ready to 🚢.

[AlexanderEggers]

@jimschubert The circleci is going to fail with the same error again. Can you help me try to figure out the root problem?

[jimschubert]

@Mordag I've opened AlexanderEggers#1 against your branch. This should resolve the CircleCI issue.

I didn't merge and fix up in master because your PR is still marked WIP, and GitHub makes it look like you did a force push after you gave thumbs up. If you merge the PR and remove WIP, then I think your changes look good and can be merged once CI is green.

Looks like the Shippable failure is just Shippable being flaky on container initialization, it was green on the previous commit, prior to the force push (which removes links to those checks)… see Shippable runs/12015

[AlexanderEggers]

@jimschubert Thanks for helping me resolving the issue with the circleci. 👍

I didn't merge and fix up in master because your PR is still marked WIP, and GitHub makes it look like you did a force push after you gave thumbs up. If you merge the PR and remove WIP, then I think your changes look good and can be merged once CI is green.

How do I remove the WIP tag? It doesn't seem that I have the needed permissions for that. The force push is only related to a rebase to master.

[jimschubert]

No problem! I've gone ahead and removed the WIP. I see now that it was added by auto-labeler and you have since changed the title (hadn't noticed that earlier).

[wing328]

@Mordag thanks for the PR, which has been included in the v4.2.1 release: https://twitter.com/oas_generator/status/1195339336922759168