Non-null InputField with default_value is not supported

[radekwlsk]

According to GraphQL spec change introduced in this pull request graphql/graphql-spec#418 it should be possible to define input field as non-null with default and make it take that default value if not provided.

• What is the current behavior?

class MyInput(graphene.InputObjectType):
    name = graphene.String(required=True)
    myInput = graphene.InputField(
        graphene.Boolean,
        default_value=True,
        required=True,
    )

input MyInput {
    name: String!
    myValue: Boolean! = true
}

when provided as {"name": "foo"} results in

{'errors': [{'message': 'Variable "$input" got invalid value {"name": "foo"}.\nIn field "myValue": Expected "Boolean!", found null.'}]}

• What is the expected behavior?

When input field has a default (true here) and is non-null providing {"name": "foo"} should results in passing {"name": "foo", "myValue": true} to the mutation and no errors.

Error

{'errors': [{'message': 'Variable "$input" got invalid value {"name": "foo"}.\nIn field "myValue": Expected "Boolean!", found null.'}]}

should only occur when input has myValue explicitly provided as null/None.

• What is the motivation / use case for changing the behavior?

That should be the default behaviour according to GraphQL spec: graphql/graphql-spec#418

[jkimbo]

@radekwlsk is this on Graphene v2? I think this should be fixed in v3 with the upgrade to graphql-core v3.

[radekwlsk]

@radekwlsk is this on Graphene v2? I think this should be fixed in v3 with the upgrade to graphql-core v3.

Yeah, that's v2. I will have to check that on v3 but not sure if our production app is ready for that jump. I will have to create some test project for it.

[radekwlsk]

@jkimbo I've bumped the dependencies to

graphql-core = "~=3.1.1"
graphene = "==3.0b3"
graphene-django = "==3.0.0b4"

and it still errors out when required input field with a default is not provided. But from what you are saying I take that it is an issue with graphql-core rather than graphene?

[jkimbo]

Hmm thats strange, I've added a test to try and show that it should work: https://github.com/graphql-python/graphene/compare/input-type-default

Can you check your code with the test that I've written?

[radekwlsk]

Same thing with your test code copied

>       assert not result.errors
E       assert not [GraphQLError('Argument "myField" has invalid value {}.\nIn field "name": Expected "String!", found null.\nIn field "goodPerson": Expected "Boolean!", found null.')]
E        +  where [GraphQLError('Argument "myField" has invalid value {}.\nIn field "name": Expected "String!", found null.\nIn field "goodPerson": Expected "Boolean!", found null.')] = <graphql.execution.base.ExecutionResult object at 0x7ff0f60c9e00>.errors

I will check dependency tree once again.

[radekwlsk]

@jkimbo Ok, I've once again installed all dependencies (correctly this time) and it indeed works on v3.

Closing

[jkimbo]

Glad to hear!