[kotlin-server] Fix class names for useTags

[feczkob]

Follow-up of #23379.

Adds support of useTags for all kotlin-server generators. The default value is true in order to avoid a breaking change. Adds a new sample for ktor2 with useTags=false.
Fixes deserialization into Any class instead of a Map that'd fail in case the response is an array for ktor2. Fixes the week-baed year to calendar year for ktor and ktor2.

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---

Summary by cubic

Fixes kotlin-server JAX-RS class naming when useTags=false, standardizes class-level JAX-RS @Path via a computed common path, and enables useTags across all kotlin-server generators with a default of true. Also fixes Ktor example deserialization and logback date patterns, and adds a ktor2 sample with useTags=false.

• Bug Fixes

  • JAX-RS (jaxrs-spec): compute commonPath per API; set class-level @Path (empty string for root) and add method @Path only for sub-resources.
  • All libraries: when useTags=false, group operations (and class names) by the first path segment; fallback to default for root or templated-only paths.
  • ktor/ktor2: deserialize example JSON to Any (Gson); fix logback pattern to use calendar year (yyyy).

• Refactors

  • Default useTags to true across all kotlin-server libraries; docs updated; remove useTags from kotlin-server-jaxrs-spec.yaml; add bin/configs/kotlin-server-ktor2-usetags-false.yaml.
  • Update templates and README to use {{commonPath}}{{path}}; guard method @Path with subresourceOperation.
  • Add samples/server/petstore/kotlin-server/ktor2-usetags-false; update tests and regenerate samples.

^{Written for commit 878b96b. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 14 files

[feczkob]

I used this repo for reproduction, thanks to @lbilger: https://github.com/lbilger/openapi-generator-path-shadowing-reproducer

JAXRS-SPEC, useTags = true

kotlin-server, JAXRS-SPEC, useTags = true

JAXRS-SPEC, useTags = false

kotlin-server, JAXRS-SPEC, useTags = false

JAXRS-SPEC, no useTags defaults to false

⚠️ kotlin-server, JAXRS-SPEC, no useTags defaults to true

[lbilger]

@feczkob I think I see more or less what you're doing here now. You want to align kotlin-server/jaxrs-spec with the "original" jaxrs-spec. If that is the main goal, the PR mostly achieves it as far as I can see. Only the docs should also state that the useTags parameter is only supported for this library, just like useMutiny already does.

This will however be a breaking change for everyone using this generator/library. Also, it deliberately excludes all the other libraries from using this parameter even though it would be no additional effort to support it for all libraries. So I suggest to at least consider making useTags=true the default, even though it is not completely in line with jaxrs-spec.

[lbilger]

It seems operationIdLowerCase is not set in the useTags=false case - probably because the super method that sets it is never called.

[feczkob]

Nice catch, fixed in c3e559b

[feczkob]

Hey @lbilger, I added a new commit c3e559b with your suggested changes. The default for useTags will be true for kotlin-server with JAXRS-SPEC, and the parent's super method will not be skipped. My goal with this PR was to match the behavior of the Java JAXR-SPEC generator, but it's reasonable to deviate from that to avoid breaking changes.

As for the future steps, I can think of a few:

• make useTags accessible for every kotlin-server generator - should be fairly easy, as you pointed out (it is included in this PR)
• simplify the addOperationToGroup() method of AbstractJavaJAXRSServerCodegen.java to match the one we propose for kotlin-server
• fix the original bug you reported for both generators

When my time permits, I'd pick up the last one in a separate PR, to finally make useTags work as expected, without the path shadowing.

[cubic-dev-ai]

3 issues found across 29 files (changes from recent commits).

Prompt for AI agents (unresolved 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/ktor2-usetags-false/src/main/resources/logback.xml">

<violation number="1" location="samples/server/petstore/kotlin-server/ktor2-usetags-false/src/main/resources/logback.xml:4">
P2: Log timestamp pattern uses week-based year (`YYYY`) instead of calendar year (`yyyy`), which can log incorrect years near New Year.</violation>
</file>

<file name="samples/server/petstore/kotlin-server/ktor2-usetags-false/src/main/kotlin/org/openapitools/server/infrastructure/ApiKeyAuth.kt">

<violation number="1" location="samples/server/petstore/kotlin-server/ktor2-usetags-false/src/main/kotlin/org/openapitools/server/infrastructure/ApiKeyAuth.kt:67">
P2: Auth provider registers without validating required config, allowing empty `apiKeyName` (and default throwing validator) to fail at runtime instead of startup.</violation>
</file>

<file name="samples/server/petstore/kotlin-server/ktor2-usetags-false/src/main/kotlin/org/openapitools/server/apis/PetApi.kt">

<violation number="1" location="samples/server/petstore/kotlin-server/ktor2-usetags-false/src/main/kotlin/org/openapitools/server/apis/PetApi.kt:100">
P1: Array response examples are deserialized as a map type (`empty::class.java`), which breaks array-root payloads and can cause runtime JSON parse failures.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: Auth provider registers without validating required config, allowing empty apiKeyName (and default throwing validator) to fail at runtime instead of startup.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/server/petstore/kotlin-server/ktor2-usetags-false/src/main/kotlin/org/openapitools/server/infrastructure/ApiKeyAuth.kt, line 67:

<comment>Auth provider registers without validating required config, allowing empty `apiKeyName` (and default throwing validator) to fail at runtime instead of startup.</comment>

<file context>
@@ -0,0 +1,102 @@
+            )
+        }
+
+        var apiKeyName: String = ""
+
+        var apiKeyLocation: ApiKeyLocation = ApiKeyLocation.QUERY
</file context>

[feczkob]

Changing this is outside of the scope of this PR. It'd be a behavioral change that should probably be first discussed with users of the generator.

[feczkob]

After all I could not resist the temptation to enable useTags for all kotlin-server generators. I added a new sample for ktor2, that's why there are so many new lines.