[BUG][KOTLIN][jvm-ktor] Inline enum array default generates invalid Kotlin -> compile error

[MattFromGer]

Description

Since 7.25.0, an inline enum array default generates invalid Kotlin:

colors: Set<String>? =
    Set<Color>.setOfLeft_ParenthesisColorPeriodRedCommaColorPeriodBlueRight_Parenthesis

Expected:

colors: Set<String>? = setOf("red", "blue")

openapi-generator version

7.25.0. Regression from 7.24.0, exposed by #24556.

OpenAPI declaration file content or url

openapi: 3.0.3
info:
  title: Reproduction
  version: 1.0.0
paths:
  /items:
    get:
      operationId: getItems
      parameters:
        - name: colors
          in: query
          schema:
            type: array
            uniqueItems: true
            items:
              type: string
              enum: [red, blue]
            default: [red, blue]
      responses:
        "204":
          description: No content

Generation Details

openapi-generator-cli generate -g kotlin -i repro.yaml -o out \
  -p library=jvm-ktor,serializationLibrary=jackson

Steps to reproduce

1. Generate the client with 7.25.0.
2. Compile the generated code.
3. Observe unresolved Color and mangled setOf... references.

Related issues/PRs

• #24556 added default values to optional jvm-ktor parameters and exposed this issue.
• #20394 reports a similar invalid default for an array of inline enum values in the Kotlin jvm-retrofit2 generator.
• #14873 concerns invalid Kotlin defaults for arrays of referenced enums.

Suggest a fix

KotlinClientCodegen.adjustEnumRefDefault() treats the complete container default as a scalar enum value. Skip containers:

if (StringUtils.isEmpty(param.defaultValue)
+       || param.isContainer
        || !(param.isEnum || param.isEnumRef)) {

Additionally, render inline enum-array parameter defaults according to their exposed type:

setOf("red", "blue")