Required `multipart/form-data` parameters not reflected in generated schema

[ali-rantakari]

Given a REST controller handler method like this (note how one parameter (stringParam) is required, while the other (fileParam) is not — as per the required property of the @RequestPart annotation):

@PostMapping("/foo", consumes = [MediaType.MULTIPART_FORM_DATA_VALUE])
fun foo(
    @RequestPart stringParam: String,
    @RequestPart(required = false) fileParam: MultipartFile?
) {}

…SpringDoc produces an API definition that looks something like this (note how neither of the parameters are marked as required):

…
"requestBody": {
  "content": {
    "multipart/form-data": {
      "schema": {
        "properties": {
          "fileParam": {
            "format": "binary",
            "type": "string"
          },
          "stringParam": {
            "type": "string"
          }
        },
        "type": "object"
      }
    }
  }
},
…

Expected: the multipart/form-data schema object in the generated spec to include "required": ["stringParam"].

Using:

• Spring boot v. 2.4.2
• springdoc-openapi-ui v. 1.5.4
• springdoc-openapi-kotlin v. 1.5.4