[KOTLIN][SPRING] Better Handling of Optional/Default Types

[dr4ke616]

Description

Few very minor bugs around how default values and required fields are handled in requestBodys and parameters. In particular in correct use of nullable types (?).

• Request bodies are not respecting the required field when provided. Therefore types are not being correctly set as null-able in controller method signatures.

requestBodies:
  MetaInfoBody:
    required: true  # no matter if set to true or false
    content:
      application/json:
        schema:
          $ref: "#/components/schemas/MetaInfo"

The above definition yields the below code no matter if required is set to true of false.

bodiesPost(@RequestBody metaInfo: MetaInfo)

• Request parameters that have default values, the types remain null-able. For example, a request parameter such as the following, which has required false but has a default value, still set the types in the RequestParam as null-able.

components:
  parameters:
    Limit:
      name: "limit"
      in: query
      required: false  # required is false, but has a default
      schema:
        type: "integer"
        minimum: 1
        maximum: 50
        default: 10

The above definition would yields:

@RequestParam(value = "limit", required = false, defaultValue = "10") limit: Int?  // <-- still null-able

openapi-generator version

Latest release - org.openapitools:openapi-generator:2.3.2