Swagger codegen generates duplicated variables

Question

I'm trying to generate client from yaml that contains

  acceptParam:
    name: Accept
    type: string
    required: true
    in: header
    description: Accepted Content-type. Should be set to application/json
  contentTypeParam:
    name: Content-Type
    type: string
    required: true
    in: header
    description: Request Content-type. Should be set to application/json

That means, accept and contentType will be present in generated method signature.

On top of that, I'v configured plugin like this

<plugin>
    <groupId>io.swagger.codegen.v3</groupId>
    <artifactId>swagger-codegen-maven-plugin</artifactId>
    <version>3.0.18</version>
    <executions>
        <execution>
            <goals>
                <goal>generate</goal>
            </goals>
            <phase>generate-sources</phase>
            <configuration>
                <inputSpec>${project.basedir}/src/main/resources/swagger.yaml</inputSpec>
                <language>java</language>
                <configOptions>
                    <dateLibrary>joda</dateLibrary>
                    <localVarPrefix>localVar</localVarPrefix>
                </configOptions>
                <library>resttemplate</library>
                <output>${project.build.directory}/generated-sources</output>
                <modelPackage>com.example.client.model</modelPackage>
                <apiPackage>com.example.client.api</apiPackage>
                <generateApiTests>false</generateApiTests>
                <generateModelTests>false</generateModelTests>
            </configuration>
        </execution>
    </executions>
</plugin>

Still, after mvn clean install

I'm getting

Error:(130,31) java: variable accept is already defined in method

And generated code contains

public Response authorize(Request body, String accept, ...) {
   ....
   final List<MediaType> accept = apiClient.selectHeaderAccept(accepts);    
   ....
}

I'v tried different versions of plugin (from 2.3.0 up to newest one), after overcoming lots of other issues, I'm always ending up like this.

Answer 1

In OpenAPI 2.0, the Accept and Content-Type headers should be defined using consumes and produces rather than parameters. In OpenAPI 3.0, these headers are defined as request/response media types.

Change your operation definition as follows:

swagger: '2.0'

paths:
  /foo:
    post:
      consumes:
        - application/json
      produces:
        - application/json
      ...

or if you use OpenAPI 3.0:

openapi: 3.0.0

paths:
  /foo:
    post:
      requestBody:
        content:
          application/json:     # <----
            schema:
              ...
      responses:
        '200':
          description: ok
          content:
            application/json:   # <----
              schema:
                ...