Do not access the internals of SimpleLazyObject

[pcraciunoiu]

This API is not meant to be used, and it breaks when double-wrapped lazy objects occur, which appears to be a long standing practice.

See original issue in django-otp django-otp/django-otp#36

This was introduced a long time ago, in v1.1.0, surprised it hasn't come up before?
d73f4aa

At any rate, if you have both AuthenticationMiddleware and Django OTP, this will blow up with:

Exception: Received incompatible instance

[pcraciunoiu]

For context, see also Django source code, which implies __class__ is the right way to check the class of a lazy object:
https://github.com/django/django/blob/4b146e0c83891fc67a422aa22f846bb7654c4d38/django/utils/functional.py#L332

[pcraciunoiu]

@jkimbo any thoughts on this? It's a fairly small change and tests pass.

[jkimbo]

@pcraciunoiu sorry for the delay. Could you add a test to this PR to show the changes working?

[pcraciunoiu]

Here you go. Before the changes, the test results in:

=============================================== FAILURES ================================================
_____________________________ test_should_query_wrapped_simplelazy_objects ______________________________

    def test_should_query_wrapped_simplelazy_objects():
        class ReporterType(DjangoObjectType):
            class Meta:
                model = Reporter
                fields = ("id",)
    
        class Query(graphene.ObjectType):
            reporter = graphene.Field(ReporterType)
    
            def resolve_reporter(self, info):
                return SimpleLazyObject(lambda: SimpleLazyObject(lambda: Reporter(id=1)))
    
        schema = graphene.Schema(query=Query)
        query = """
            query {
              reporter {
                id
              }
            }
        """
        result = schema.execute(query)
>       assert not result.errors
E       assert not [Exception('Received incompatible instance " ".',)]
E        +  where [Exception('Received incompatible instance " ".',)] = <graphql.execution.base.ExecutionResult object at 0x7f434877bdc8>.errors

graphene_django/tests/test_query.py:84: AssertionError
------------------------------------------- Captured log call -------------------------------------------
ERROR    graphql.execution.utils:utils.py:155 Traceback (most recent call last):
  File "/home/paul/.local/share/virtualenvs/graphene-django-aq2KKQnM/lib/python3.6/site-packages/graphql/execution/executor.py", line 481, in complete_value_catching_error
    exe_context, return_type, field_asts, info, path, result
  File "/home/paul/.local/share/virtualenvs/graphene-django-aq2KKQnM/lib/python3.6/site-packages/graphql/execution/executor.py", line 572, in complete_value
    exe_context, return_type, field_asts, info, path, result
  File "/home/paul/.local/share/virtualenvs/graphene-django-aq2KKQnM/lib/python3.6/site-packages/graphql/execution/executor.py", line 712, in complete_object_value
    if return_type.is_type_of and not return_type.is_type_of(result, info):
  File "/home/paul/Projects/graphene-django/graphene_django/types.py", line 277, in is_type_of
    raise Exception(('Received incompatible instance "{}".').format(root))
Exception: Received incompatible instance " ".

I tried setting up the middleware to do it, but there's no pattern of tests that use Django's middleware yet, so I hope this will suffice. Lazy should be allowed to work when they're chained and now that part's tested.

[jkimbo]

Great thanks!

[pcraciunoiu]

Thank you too @jkimbo can you say if this will make it into graphene-django 2 as well as 3?

Ah looks like I just missed today's release :/ hope there will be one in the next couple of weeks.

[jkimbo]

@pcraciunoiu yep I'll release this as part of v2.10.1 soon. I was just going to wait a couple of days to see if there are any issues that come up as a result of the v2.10.0 release.

[pcraciunoiu]

@jkimbo thoughts on a release with the fix this week?

[jkimbo]

@pcraciunoiu sorry for the delay. Just released v2.10.1 with your fix: https://github.com/graphql-python/graphene-django/releases/tag/v2.10.1