Support RequestBody as a meta-annotation

[edudar]

Problem:

io.swagger.v3.oas.annotations.parameters.RequestBody has three targets it can be used on:

• METHOD
• PARAMETER
• ANNOTATION_TYPE

When springdoc resolves annotation in AbstractRequestService.isRequestBodyParam(), it checks if there's such annotation on a parameter directly:

methodParameter.getParameterAnnotation(RequestBody.class) != null

or on a method:

AnnotatedElementUtils.findMergedAnnotation(methodParameter.getMethod(), RequestBody.class) != null

but it does not cover ANNOTATION_TYPE, so any annotation that would use RequestBody as a meta-annotation won't work. This is my case, as I have a special annotation for the request body that is not native to Spring.

Workaround:

Use two annotations:

@MyRequestBody @io.swagger.v3.oas.annotations.parameters.RequestBody

I use full path because the name is the same between one in Swagger and one in Spring, and there are mix-ups.

Solution:

Check if RequestBody is a meta-annotation:

AnnotatedElementUtils.findMergedAnnotation(methodParameter.getParameter(), RequestBody.class) != null

This should cover both PARAMETER and ANNOTATION_TYPE cases.