[BUG][JAVA][SERVER] In release 6.2.1, spring server generator creates wrong annotation on method parameter for multipart request

Created by: raverone

Description

Spring server genertor creates wrong annotation on method parameter for multipart request. The request have 2 parameters:

SomeObject param1
MultipartFile param2

In version 5.4.0 both parameters would be annotated with @RequestPart. Which is correct.

But starting from version 6.0.0 (until the 6.2.1 at least) param1 would be annotated with @RequestParam and param2 with @RequestPart. In this case, if you make a call to such endpoint, Spring won't be able to convert the request parameters and will throw

org.springframework.web.method.annotation.MethodArgumentConversionNotSupportedException:
Failed to convert value of type 'java.lang.String' to required type 'org.example.http.model.SomeObject';
...
no matching editors or conversion strategy found

openapi-generator version

6.2.1

OpenAPI declaration file content or url

Gist

Generation Details

Generation is done with the gradle plugin by executing ./gradlew :openApiGenerate

Steps to reproduce

I created a minimal project on github Steps to reproduce the bug:

clone the repo
cd into the repo directory
execute ./gradlew :openApiGenerate
examine file build/generated/src/main/java/org/example/bug/http/api/TestApiApi.java
- Expected generated code

default ResponseEntity<SomeResponse> uploadFileAndJson(
        @RequestPart(value = "someObject", required = true) SomeObject someObject,
        @RequestPart(value = "image", required = true) MultipartFile image
    )

- Actual generated code

default ResponseEntity<SomeResponse> uploadFileAndJson(
        @RequestParam(value = "someObject", required = true) SomeObject someObject,
        @RequestPart(value = "image", required = true) MultipartFile image
    )

you can also execute tests with ./gradlew -i :test. It should pass, but currently it isn't.