Turning Non-null to is_null about graphene HOT 3 CLOSED

I'd do the PR myself, but I wonder to see if that's something maintainers agree with me or not.

from graphene.

Graphql has a weird relationship with nullable field.
The nuance of "a required nullable field" is not achievable as far as I know in the schema definition... indeed the "no value" is null and is valid for optional fields too.
Meaning that

type Mutation {
  doNothing(input: DoNothingInput!): DoNothingPayload
}

type DoNothingPayload {
  nullableInt: Int
}

input DoNothingInput {
  nullableInt: Int
}

that can be obtained with:

nullable_int = graphene.Int(required=False)

serves both purposes of being nullable and being optional.

Indeed you can do the following 3 behavior:

• you provide an actual integer input:

mutation {
    doNothing(input: { nullableInt: 1 }) {
        nullableInt
    }
}

and in your resolver "nullable_int" in input is True (and input.nullable_int is 1 and input["nullable_int"] is 1 )

• you can provide null input:

mutation {
    doNothing(input: { nullableInt: null }) {
        nullableInt
    }
}

and in your resolver "nullable_int" in input is True (and input.nullable_int is None and input["nullable_int"] is None )

• you can provide no input at all:

mutation {
    doNothing(input: { }) {
        nullableInt
    }
}

and in your resolver "nullable_int" in input is False (and input.nullable_int is None and input["nullable_int"] actually fails)

So if you want to have a required nullable input, your only way to do it is to make the type required=False and add an assertion in your mutation

assert "nullable_int" in input

There is no way as far as I know to enforce that at schema level...

from graphene.

Note that this issue is an open conversation in the grapqh specs: graphql/graphql-spec#476

from graphene.