Convert DecimalField to String rather than Float

DecimalField entries are currently being converted to Float (https://github.com/graphql-python/graphene-django/blob/8f5a425859ea380d0640c441c5c7f3b1acae17b4/graphene_django/form_converter.py#L56-L59)

Full support for Decimal would be great, but in the meantime I propose that DecimalField should be converted to String instead. Once you’ve converted a Decimal to a Float, you’ve probably lost the benefit of why you used Decimal in the first place, since you’ll now have values like 3.14000000000000012, rather than 3.14. If it is converted to String, it is simple enough for the user to convert that String back to Decimal, whereas converting from Float to Decimal is not straightforward.

[picturedots]

As a workaround for this particular problem, I created a Decimal type, and then am explicitly setting that field in the DjangoObjectType class. For example, I created a Decimal type like this

import decimal

from graphene.types import Scalar
from graphql.language import ast

class Decimal(Scalar):
    """ 
    The `Decimal` scalar type represents a python Decimal.
    """
    @staticmethod
    def serialize(dec):
        assert isinstance(dec, decimal.Decimal), (
            'Received not compatible Decimal "{}"'.format(repr(dec))
        )
        return str(dec)
    
    @staticmethod
    def parse_value(value):
        return decimal.Decimal(value)
    
    @classmethod
    def parse_literal(cls, node):
        if isinstance(node, ast.StringValue):
            return cls.parse_value(node.value)

and then explicitly replace the field like this:

class MyModelType(DjangoObjectType):
    my_decimal_field = Decimal()
    class Meta:
        model = MyModel

assuming that I have a Django model MyModel with Decimal field my_decimal_field.

[i6mi6]

Has this been documented in the changelog? It broke our existing app logic because now suddenly we started getting strings rather than floats. Is there a way to default to previous behavior?