[Bug] Generating incorrect OpenAPI specifications when using @Form for headers and queryString.

[Tijs-2]

I see an issue inside the openapi spec when using @Form in combination with @Header or @QueryParam.
The openapi spec validator also says the generated spec is invalid: GET operations cannot have a requestBody.

This happens when I create a Form like this:

public class TestForm {
    @QueryParam
    String queryParameter;
    @Header
    String headerParameter;
}

And use it like the following: (the test3 endpoints seem to generate a correct openapi spec.).

@Controller("/test")
public class TestController {
    @Form
    @Get("/test")
    public String testGet(final TestForm form) {
        return form.headerParameter + " " + form.queryParameter;
    }

    @Get("/test2")
    public String testGet2(@Form final TestForm form) {
        return form.headerParameter + " " + form.queryParameter;
    }

    @Get("/test3")
    public String testGet3(@Header final String headerParameter, @QueryParam final String queryParameter) {
        return headerParameter + " " + queryParameter;
    }

    @Form
    @Post("/test")
    public String testPost(final TestForm form) {
        return form.headerParameter + " " + form.queryParameter;
    }

    @Post("/test2")
    public String testPost2(@Form final TestForm form) {
        return form.headerParameter + " " + form.queryParameter;
    }

    @Post("/test3")
    public String testPost3(@Header final String headerParameter, @QueryParam final String queryParameter) {
        return headerParameter + " " + queryParameter;
    }
}

I would expect in the OpenAPI spec that they are all the a same /test3 but the strange thing is then they are not a header parameter but set like the following:

    "paths" : {
        "/test/test" : {
            "get" : {
                "tags" : [
                ],
                "summary" : "",
                "description" : "",
                "requestBody" : {
                    "content" : {
                        "application/x-www-form-urlencoded" : {
                            "schema" : {
                                "$ref" : "#/components/schemas/TestForm"
                            }
                        }
                    },
                    "required" : true
                },
                "responses" : {
                    "200" : {
                        "description" : "",
                        "content" : {
                            "application/json" : {
                                "schema" : {
                                    "type" : "string"
                                }
                            }
                        }
                    }
                }
            }
		}
	},
    "components" : {
        "schemas" : {
			"TestForm" : {
				"type" : "object",
				"properties" : {
					"queryParameter" : {
						"type" : "string"
					},
					"headerParameter" : {
						"type" : "string"
					}
				}
		    }
	    }
	}

I think it should be like the test3 endpoint.

"/test/test3" : {
	"get" : {
		"tags" : [
			
		],
		"summary" : "",
		"description" : "",
		"parameters" : [
			{
				"name" : "Header-Parameter",
				"in" : "header",
				"schema" : {
					"type" : "string"
				}
			},
			{
				"name" : "queryParameter",
				"in" : "query",
				"schema" : {
					"type" : "string"
				}
			}
		],
		"responses" : {
			"200" : {
				"description" : "",
				"content" : {
					"application/json" : {
						"schema" : {
							"type" : "string"
						}
					}
				}
			}
		}
	}
}

The generated code seems valid and uses the queryParam and header values.

openapi.json

[SentryMan]

@Form shouldn't be used on GET methods, I can add a compile error for that if you like.

EDIT: Hmm, wait a minute