[kotlin][kotlin-spring] Keep the Map type for properties whose additionalProperties is an inline enum

FI
8h ago
+82-4

Description:

With the kotlin and kotlin-spring generators, an object property whose additionalProperties is an inline enum was typed as the nested enum (val lessonStatus: Today.LessonStatus) instead of a map of it. Such a property is flagged isEnum, and the data class property templates only special-cased arrays, so the Map was lost and decoding the JSON object failed.

The property templates now wrap the nested enum in a map when isMap is set, the same way lists of inline enums are already handled:

  • kotlin-client/data_class_req_var.mustache and data_class_opt_var.mustache: kotlin.collections.Map<kotlin.String, Today.LessonStatus> (MutableMap with modelMutable)
  • kotlin-spring/dataClassReqVar.mustache and dataClassOptVar.mustache: Map<kotlin.String, Today.LessonStatus>

Not addressed here: a map of lists or of maps of inline enums, the interface property templates, and nullable map values in kotlin-spring.

I added a test in KotlinClientCodegenModelTest and one in KotlinSpringServerCodegenTest with 3_0/kotlin/issue25453-map-of-inline-enum.yaml. Both fail without the change. samples/ has no diff.

Fixes #25453

PR checklist

  • Read the contribution guidelines.
  • Run the following to build the project and update samples (see below for what I ran instead): 
    ./mvnw clean package || exit
./bin/generate-samples.sh ./bin/configs/*.yaml || exit
./bin/utils/export_docs_generators.sh || exit
  • If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

What I ran on this branch (macOS, JDK 21, Maven wrapper):

  • ./mvnw -pl modules/openapi-generator -am test -Dtest=KotlinClientCodegenModelTest,KotlinClientCodegenApiTest,KotlinModelCodegenTest,KotlinSpringServerCodegenTest passes (436 tests, 0 failures, 4 skipped). With the four templates put back to master, the two new tests fail.
  • ./bin/generate-samples.sh with the 104 kotlin and kotlin-spring configs exits 0 and leaves samples/ unchanged.
  • I generated a jvm-retrofit2 kotlinx client from the issue spec and built it with its Gradle wrapper. With this change it compiles, and a small local test (not committed) decodes {"lessonStatus":{"l1":"ready","l2":"failed"}} and reads lessonStatus["l1"]. With master templates the same decode fails with JsonDecodingException ... at path: $.lessonStatus.
  • I generated the kotlin-spring server from the issue spec and compiled it with mvn compile on its generated pom.xml (its Gradle 8.1.1 wrapper does not run on JDK 21, with or without this change). The property is Map<String, Today.LessonStatus> with the change and Today.LessonStatus on master.

I did not run the full ./mvnw clean package, the other sample configs or ./bin/utils/export_docs_generators.sh, so the second box is unchecked. No option or docs text changed.

cc @karismann @Zomzog @andrewemery @4brunu @yutaka0m @stefankoppier @e5l

Summary by cubic

Fixes the kotlin and kotlin-spring generators emitting object properties whose additionalProperties is an inline enum as the bare nested enum instead of a Map, which broke JSON decoding.

Details

  • Data class property templates now emit kotlin.collections.Map<kotlin.String, ...> (or MutableMap with modelMutable in the kotlin client) when the property is an enum map, matching how lists of inline enums are handled.
  • Adds tests in both generators covering required, optional, and nullable map-of-inline-enum properties.
  • Not addressed: maps of lists or maps of inline enums, interface property templates, and nullable map values in kotlin-spring.

Fixes #25453.