Include known error responses in OpenAPI metadata/generated OpenAPI doc

[mikekistler]

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe the problem.

There are some cases where the framework / middleware pipeline can generate error responses, such as when the endpoint defines a required parameter -- if the parameter is not present in the request, the framework generates a status code 400 response. And if the ProblemDetails service was added to the DI container, it is used to generate a ProblemDetails response body for this.

However, these responses are not represented in the generated OpenAPI document.

Describe the solution you'd like

For the case indicated, and perhaps others, these responses should be included in the generated OpenAPI document. However, I think we'll want to be careful about this -- for example I'm not sure we should add 401 and 403 responses for operations that require authentication.

Additional context

No response

[sander1095]

Hi Mike!

Are you talking about OpenAPI's default response here? For example, when I create a Minimal API endpoint that I set up to return a 200 OK with TodoItem DTO's, would the document have an additional default response pointing to the ProblemDetails schema in case an unknown/unhandled exception occurs in the endpoint?

[mikekistler]

I'm not really referring to "default". I'm thinking of more specific cases like parameter validation that fails with a 400 response.

I am not a fan of "default" as I believe it is too broad -- it could cover 1xx or 3xx responses for example.