I'm trying to figure out a way to return None for non-nullable fields if the requesting user doesn't have permission to view them.

I was trying to pass Undefined from graphql.pyutils.undefined, but it doesn't work. It looks like the second check in this line

# If result value is null or undefined then return null.
if result is None or result is Undefined:
    return None

can never run because Undefined is actually a descendant of ValueError and therefore triggers this check.

if isinstance(result, Exception):
    raise result

I don't know if this was meant as an escape hatch for returning null values if you really wanted to (which is what I really need right now), but the code itself seems wrong either way.