GraphQLLocatedError at schema dump for date values

[iyawnis]

• What is the current behavior?

When trying to dump a schema using the graphql_schema command that contains the following default date value:

class MyQuery(graphene.ObjectType):
    field = graphene.ConnectionField(
        type=MyQueryConnectionType,
        start_date=graphene.Argument(
            graphene.Date,
            default_value=date.min,
            description="Earliest `date` value my query",
        ),

An error is raised from site-packages/graphql/utils/ast_from_value.py", line 53, in ast_from_value

Adding the following above the error line:

    if isinstance(value, datetime.date):
        return ast.StringValue(value.isoformat())

solves the issue. Is this the appropriate solution to this problem ?

• What is the expected behavior?

The schema to generate without error. Using the above fix the following entry is generated:

                  "defaultValue": "\"0001-01-01\"",
                  "description": "Earliest `date` value for my query",
                  "name": "startDate",
                  "type": {
                    "kind": "SCALAR",
                    "name": "Date",
                    "ofType": null
                  }
                },

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

Be able to generate a schema with date values as default parameters to arguments.

• Please tell us about your environment:

graphene==2.1.9 graphene-django==2.15.0 Python 3.10