[JAVA] text/plain as response type throws exception

Description

I use the swagger-codegen-maven-plugin and POST to an endpoint which returns "text/plain", which is in the swagger 2.0 spec.

It throws this exception
"Content type "" + contentType + "" is not supported for type: " + returnType,
Content type plain/text;charset=UTF-8 is not supposed for type ..ResponseEntity

I kind of fixed this myself by adding this, though it isn't very pretty

} else if (isTextMime(contentType)) {
return (T) new ResponseEntity().body(respBody).statusCodeValue(response.code());
}

and my own isTextMime function

It's the deserialize function in the generated ApiClient that's failing.

• Deserialize response body to Java object, according to the return type and
  • the Content-Type response header.

Swagger-codegen version

2.3.1 (I could not get 3.0.0 to run)

Swagger declaration file content or url

We had some issues with the swagger spec, but I got those devs to fix the issues, and it did not seem to help.

The base from the spec:
{"swagger":"2.0","info":{"description":"xx","version":"1",
"title":"xHub REST API","termsOfService":"none","contact":{"name":"none"},
"license":{"name":"none","url":"http://www.nolicense.com"}}
,"host":"xx:8051","basePath":"/",
"tags":[..],"schemes":["http"]

The request :

,"/testdata/xx/{env}/live/{live}"
:{"post":{"tags":["Testdata"],"summary":"","operationId":"","consumes":["application/json"],"produces":["text/plain"],
"parameters":[{"name":"env","in":"path","description":"env","required":true,"type":"string"},
{"name":"live","in":"path","description":"live","required":true,"type":"boolean"},
{"in":"body","name":"request","description":"request","required":true,"schema":{"$ref":"#/definitions/xxDTO"}}],
"responses":{"200":{"description":"OK","schema":{"$ref":"#/definitions/ResponseEntity"}},"201":{"description":"Created"},
"401":{"description":"Unauthorized"},"403":{"description":"Forbidden"},"404":{"description":"Not Found"}}}}

Command line used for generation

Just the codegen plugin, generating model, api and supporting files

Steps to reproduce

Get "text/plain" as content-type in response to a request (a POST in my case)

Related issues/PRs

I could not find the same issue anywhere.. Although I feel like I'm doing something wrong..

The issue points to the generated ApiClient's deserialize function; start there and trace handling of a text/plain response with a ResponseEntity return type. Reproduce the POST response described in the issue, then verify that deserialization no longer throws and returns the response body; no test file is named in the report.