[kotlin-server][JAX-RS] Add useTags to kotlin-server JAXRS code generator

[feczkob]

Fixes #20342

@karismann @Zomzog @andrewemery @4brunu @yutaka0m @stefankoppier @e5l @dennisameling could you please take a look?

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Summary by cubic

Adds a useTags option to the kotlin-server JAXRS generator to control API grouping/class names and computes a commonPath for cleaner class-level @Path and docs. Fixes #20342.

• New Features

  • New additionalProperty: useTags (JAXRS-spec only). When true or not set, group by tags; when false, group by the first path segment.
  • Computes commonPath per API and applies @Path("{{commonPath}}") at the class level; method-level @Path uses remaining segments. README/docs now show full paths (commonPath + operation path).
  • Updates docs, config, tests, and samples to reflect the option and path changes.

• Bug Fixes

  • Default behavior respected when useTags is absent (group by tags) and avoids emitting @Path("/") by using an empty path for the root.

^{Written for commit 3ed2af6. Summary will update on new commits.}

[cubic-dev-ai]

2 issues found across 10 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="samples/server/petstore/kotlin-server/jaxrs-spec/README.md">

<violation number="1" location="samples/server/petstore/kotlin-server/jaxrs-spec/README.md:37">
P2: README API endpoint table now omits resource prefixes (e.g., /pet, /store, /user), producing incomplete paths and misleading documentation.</violation>
</file>

<file name="modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinServerCodegen.java">

<violation number="1" location="modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinServerCodegen.java:788">
P2: Default useTags=false is ignored unless the option is explicitly provided, so omitted configuration falls back to tag-based grouping (useTags=true behavior), contradicting the documented default.</violation>
</file>

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[wing328]

Thanks for the PR but your commit (as shown in the Commits tab) is not linked to your Github account, which means this PR won't count as your contribution in https://github.com/OpenAPITools/openapi-generator/graphs/contributors.

Let me know if you need help fixing it.

Ref: https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-can-i-update-commits-that-are-not-linked-to-my-github-account

[wing328]

please resolve the merge conflicts when you've time

[feczkob]

@wing328 thanks for the info, I force pushed with my updated e-mail. Should I regenerate the samples again? I saw some changes in samples seemingly unrelated to my feature, no idea why that was. Thanks for helping me out, this is my first PR here and I can use some guidance 😄