Remove "nullable" in OAS 3.1?

Now that we have decided to discard SemVer (see PR #2243), IIRC it briefly came up on the last call that we could outright drop nullable instead of requiring that both nullable and type: "null" be supported.

Should we do this? I’d be happy to write a PR.

[handrews]

@rwalle61 it’s not much mentioned because it’s covered by JSON Schema and OAS 3.1 tries to avoid duplicating the JSON Schema spec unless it is needed to explain how JSON Schema and OAS-specific concepts interact.

What you are looking for is:

type: object
properties:
  foo:
    type: [string, "null"]

That’s the string "null", not the value null. The string "null" is the name of the type of the value null. The values in the type array can be in any order.

[rwalle61]

Thanks for this and https://github.com/OAI/OpenAPI-Specification/pull/2246!

To confirm, how should an openapi doc describe an object with a property ‘foo’ that can be string or null - just like this?

type: object
properties:
  foo:
    type: string

I couldn’t find this described anywhere, and OpenAPI 3.1.0 barely mentions null.

Out of interest, is there any summary of why null has been removed since OpenAPI 3.0.3?

And fyi you may want to update this proposal about nullable to clarify that it was rejected 😃

(I maintain an OpenAPI tool and a user has asked about using nullable)

Thanks again 😄