Swagger2; issue making array items nullable

Hi,

I’m evaluating adoption of the Swagger2Module (which seems pretty flexible!) and I noticed that I was unable to apply nullable = true to the items of an array.

Configuration

Dependencies: 4.19.0 Generator:

Swagger2Module swagger2Module = new Swagger2Module();
SchemaGeneratorConfigBuilder configBuilder = new SchemaGeneratorConfigBuilder(SchemaVersion.DRAFT_2019_09,
    OptionPreset.PLAIN_JSON)
    .with(Option.VALUES_FROM_CONSTANT_FIELDS,
        Option.MAP_VALUES_AS_ADDITIONAL_PROPERTIES,
        Option.FORBIDDEN_ADDITIONAL_PROPERTIES_BY_DEFAULT,
        Option.FLATTENED_OPTIONALS)
    .with(swagger2Module);

POJO:

@ArraySchema(
    arraySchema = @Schema(description = "Description on root field"),
    schema = @Schema(
        nullable = true,
        description = "Description on individual items"))
private Set<String> features = Set.of();

Expectation

"features" : {
    "description" : "Description on root field",
    "type" : "array",
    "items" : {
      "type" : ["string", "null"],
      "description" : "Description on individual items"
    }
}

Generated

"features" : {
    "description" : "Description on root field",
    "type" : "array",
    "items" : {
      "type" : "string",
      "description" : "Description on individual items"
    }
}

Is it clear from my configuration why this is happening? Setting @Schema(nullable = true) seems to work for non-lists/arrays.

Thanks.

[erodewald]

Fantastic! I go on one little weekend vacation and there it is! 🎉 Thank you @CarstenWickner, I will be sure to reach out if I can identify any issues.

[CarstenWickner]

The change has just been released in version 4.20.0. The new behavior is only available when explicitly enabling the new Option.NULLABLE_ARRAY_ITEMS_ALLOWED.