form-data can't be used in requestBodies block

[Alex009]

when we use form-data we can use it just as in sample:

openapi: 3.0.0
info:
  title: API
  version: v1
paths:
  /v1/auth/signup:
    post:
      tags:
        - Auth
      summary: Create user
      operationId: 'signup'
      requestBody:
        description: |
          Content-Type: multipart/form-data; boundary=boundary

          --boundary
          Content-Disposition: form-data; name="signup"

            {
              "firstName": "Andrey",
              "lastName": "Kim",
              "middleName": "Vladimirovich",
              "phone": "71111111111",
              "email": "[email protected]",
              "password": "mypassword",
              "passwordRepeat": "mypassword",
              "post": "CEO",
              "countryId": 10,
              "cityId": 11
            }
          --boundary
          Content-Disposition: form-data; name="avatar"; filename="avatar.png";

          < ./avatar.png

          --boundary--
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                signup:
                  $ref: '#/components/schemas/SignupRequest'
                  required: true
                avatar:
                  type: string
                  format: binary
      responses:
        '200':
          description: 'Ok'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Response'
        '422':
          description: 'Validation error'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ValidationErrorResponse'
        '500':
          description: 'Internal Server Error'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  schemas:
    Response:
      description: 'Basic response'
      required:
        - status
        - message
        - timestamp
        - success
      properties:
        status:
          description: Http status code
          type: integer
        message:
          description: Response message
          type: string
        timestamp:
          description: Response timestamp
          type: number
          format: int64
        success:
          description: Response status
          type: boolean
      type: object
    ResponseList:
      description: 'Basic response list'
      required:
        - status
        - message
        - timestamp
        - success
        - totalCount
      properties:
        status:
          description: Http status code
          type: integer
        message:
          description: Response message
          type: string
        timestamp:
          description: Response timestamp
          type: number
          format: int64
        success:
          description: Response status
          type: boolean
        totalCount:
          description: Response totlal list count
          type: integer
      type: object
    ErrorResponse:
      description: 'Error response'
      allOf:
        - $ref: '#/components/schemas/Response'
        - type: object
          properties:
            success:
              type: boolean
              default: false
    ValidationErrorResponse:
      description: 'Validation Error Response'
      allOf:
        - $ref: '#/components/schemas/ResponseList'
        - type: object
          properties:
            data:
              type: array
              items:
                $ref: '#/components/schemas/ErrorDetail'
    ErrorDetail:
      description: 'Error detail'
      required:
        - message
        - code
      properties:
        message:
          type: string
          description: Error message
        code:
          type: integer
          description: Error code
      type: object
    SignupRequest:
      type: object
      required:
        - firstName
        - lastName
        - phone
        - email
        - password
        - passwordRepeat
        - countryId
        - cityId
        - company
      properties:
        firstName:
          type: string
        lastName:
          type: string
        middleName:
          type: string
        phone:
          type: string
          example: 79999999999
        email:
          type: string
          format: email
        password:
          type: string
          format: password
        passwordRepeat:
          type: string
          format: password
        post:
          type: string
        countryId:
          type: integer
        cityId:
          type: integer
        company:
          type: string
        interests:
          type: string

BUT if we just extract this request body to requestBodies block - generation will be failed:

openapi: 3.0.0
info:
  title: API
  version: v1
paths:
  /v1/auth/signup:
    post:
      tags:
        - Auth
      summary: Create user
      operationId: 'signup'
      requestBody:
        $ref: "#/components/requestBodies/UploadFile"
      responses:
        '200':
          description: 'Ok'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Response'
        '422':
          description: 'Validation error'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ValidationErrorResponse'
        '500':
          description: 'Internal Server Error'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  requestBodies:
    UploadFile:
      description: |
        Content-Type: multipart/form-data; boundary=boundary

        --boundary
        Content-Disposition: form-data; name="signup"

          {
            "firstName": "Andrey",
            "lastName": "Kim",
            "middleName": "Vladimirovich",
            "phone": "71111111111",
            "email": "[email protected]",
            "password": "mypassword",
            "passwordRepeat": "mypassword",
            "post": "CEO",
            "countryId": 10,
            "cityId": 11
          }
        --boundary
        Content-Disposition: form-data; name="avatar"; filename="avatar.png";

        < ./avatar.png

        --boundary--
      content:
        multipart/form-data:
          schema:
            type: object
            properties:
              signup:
                $ref: '#/components/schemas/SignupRequest'
                required: true
              avatar:
                type: string
                format: binary
  schemas:
    Response:
      description: 'Basic response'
      required:
        - status
        - message
        - timestamp
        - success
      properties:
        status:
          description: Http status code
          type: integer
        message:
          description: Response message
          type: string
        timestamp:
          description: Response timestamp
          type: number
          format: int64
        success:
          description: Response status
          type: boolean
      type: object
    ResponseList:
      description: 'Basic response list'
      required:
        - status
        - message
        - timestamp
        - success
        - totalCount
      properties:
        status:
          description: Http status code
          type: integer
        message:
          description: Response message
          type: string
        timestamp:
          description: Response timestamp
          type: number
          format: int64
        success:
          description: Response status
          type: boolean
        totalCount:
          description: Response totlal list count
          type: integer
      type: object
    ErrorResponse:
      description: 'Error response'
      allOf:
        - $ref: '#/components/schemas/Response'
        - type: object
          properties:
            success:
              type: boolean
              default: false
    ValidationErrorResponse:
      description: 'Validation Error Response'
      allOf:
        - $ref: '#/components/schemas/ResponseList'
        - type: object
          properties:
            data:
              type: array
              items:
                $ref: '#/components/schemas/ErrorDetail'
    ErrorDetail:
      description: 'Error detail'
      required:
        - message
        - code
      properties:
        message:
          type: string
          description: Error message
        code:
          type: integer
          description: Error code
      type: object
    SignupRequest:
      type: object
      required:
        - firstName
        - lastName
        - phone
        - email
        - password
        - passwordRepeat
        - countryId
        - cityId
        - company
      properties:
        firstName:
          type: string
        lastName:
          type: string
        middleName:
          type: string
        phone:
          type: string
          example: 79999999999
        email:
          type: string
          format: email
        password:
          type: string
          format: password
        passwordRepeat:
          type: string
          format: password
        post:
          type: string
        countryId:
          type: integer
        cityId:
          type: integer
        company:
          type: string
        interests:
          type: string

in log we will see:

The following schema has undefined (null) baseType. It could be due to form parameter defined in OpenAPI v2 spec with incorrect consumes. A correct 'consumes' for form parameters should be 'application/x-www-form-urlencoded' or 'multipart/?'
schema: class ObjectSchema {
    class Schema {
        type: object
        format: null
        $ref: null
        description: null
        title: null
        multipleOf: null
        maximum: null
        exclusiveMaximum: null
        minimum: null
        exclusiveMinimum: null
        maxLength: null
        minLength: null
        pattern: null
        maxItems: null
        minItems: null
        uniqueItems: null
        maxProperties: null
        minProperties: null
        required: null
        not: null
        properties: {signup=class Schema {
            type: null
            format: null
            $ref: #/components/schemas/SignupRequest
            description: null
            title: null
            multipleOf: null
            maximum: null
            exclusiveMaximum: null
            minimum: null
            exclusiveMinimum: null
            maxLength: null
            minLength: null
            pattern: null
            maxItems: null
            minItems: null
            uniqueItems: null
            maxProperties: null
            minProperties: null
            required: null
            not: null
            properties: null
            additionalProperties: null
            nullable: null
            readOnly: null
            writeOnly: null
            example: null
            externalDocs: null
            deprecated: null
            discriminator: null
            xml: null
        }, avatar=class BinarySchema {
            class Schema {
                type: string
                format: binary
                $ref: null
                description: null
                title: null
                multipleOf: null
                maximum: null
                exclusiveMaximum: null
                minimum: null
                exclusiveMinimum: null
                maxLength: null
                minLength: null
                pattern: null
                maxItems: null
                minItems: null
                uniqueItems: null
                maxProperties: null
                minProperties: null
                required: null
                not: null
                properties: null
                additionalProperties: null
                nullable: null
                readOnly: null
                writeOnly: null
                example: null
                externalDocs: null
                deprecated: null
                discriminator: null
                xml: null
            }
        }}
        additionalProperties: null
        nullable: null
        readOnly: null
        writeOnly: null
        example: null
        externalDocs: null
        deprecated: null
        discriminator: null
        xml: null
    }
}
codegenModel is null. Default to UNKNOWN_BASE_TYPE

and in code will be used UNKNOWN_BASE_TYPE:

    /**
    * Create user
    * 
    * @param UNKNOWN_BASE_TYPE Content-Type: multipart/form-data; boundary=boundary  --boundary Content-Disposition: form-data; name=\"signup\"    {     \"firstName\": \"Andrey\",     \"lastName\": \"Kim\",     \"middleName\": \"Vladimirovich\",     \"phone\": \"71111111111\",     \"email\": \"[email protected]\",     \"password\": \"mypassword\",     \"passwordRepeat\": \"mypassword\",     \"post\": \"CEO\",     \"countryId\": 10,     \"cityId\": 11   } --boundary Content-Disposition: form-data; name=\"avatar\"; filename=\"avatar.png\";  < ./avatar.png  --boundary--  (optional)
    * @return Response
    */
    suspend fun signup(UNKNOWN_BASE_TYPE: UNKNOWN_BASE_TYPE? = null) : Response