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Description

During migration from java to kotlin Open API generator we encountered some issues with Map<String, Any?> data type. Our use case is:

1. Application A has a data class with a val dynamicProperties: Map<String, Any?> field in the API model
2. We use sprindocs openapi-gradle-plugin gradle plugin in version 1.7.0 to generate openApi.yml specification
3. We use org.openapi.generator gradle plugin in version 7.0.0 with configuration described in Generation Details to generate SDKs for API
4. Data class mentioned in point 1 has a val dynamicProperties: Map<String, Any> field in generated code.

Nullability of the values in this map is important for us and we don't want to change it.

Would it be possible to support nullable value types in kotlin maps?

openapi-generator version

7.0.0

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: OpenAPI Petstore
  license:
    name: Apache-2.0
    url: https://www.apache.org/licenses/LICENSE-2.0.html
  version: 1.0.0
paths:
  /nullableMapValue:
    get:
      responses:
        '200':
          description: 'nullable map value'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ExampleClass'
components:
  schemas:
    ExampleClass:
      required:
        - dynamicProperties
      type: object
      properties:
        dynamicProperties:
          type: object
          additionalProperties:
            type: object

Generation Details

Gradle org.openapi.generator plugin in version 7.0.0 was used with following configuration:

openApiGenerate {
  val packageName = "org.example"
  generatorName.set("kotlin")
  library.set("jvm-spring-webclient")
  inputSpec.set(tasks.generateOpenApiDocs.flatMap { it.outputFile })
  outputDir.set("$buildDir/generated/open-api-client")
  this.packageName.set(packageName)
  apiPackage.set("$packageName.api")
  modelPackage.set("$packageName.model")
  configOptions.set(
    mapOf(
      "serializationLibrary" to "jackson",
      "dateLibrary" to "java8",
      "useSpringBoot3" to "false",
      "enumPropertyNaming" to "UPPERCASE"
    )
  )
  importMappings.set(
    mapOf(
      "Pageable" to "org.springframework.data.domain.Pageable"
    )
  )
}

Steps to reproduce

It is reproducable by adding this test case to KotlinModelCodegenTest.java while having attached yaml added to test resources:

@Test(dataProvider = "generators")
    public void mapWithNullableValues(AbstractKotlinCodegen codegen) throws IOException {
        String outputPath = generateModels(codegen, "src/test/resources/3_0/maps-with-nullable-values.yaml", false);

        assertFileContains(
            Paths.get(outputPath + "/src/main/kotlin/models/ExampleClass.kt"),
            "val dynamicProperties: kotlin.collections.Map<kotlin.String, kotlin.Any>"
        );
    }

Related issues/PRs

No related issues found.