[FIXED] How to inherit Input inner class in Python graphene mutation to another Input inner class in another mutation?

Issue

I am creating a simple GraphQL request app in the backend using Django with graphene-django package. Waht I need is to inherit the Input inner class in the create mutation to the Input class for the update mutation. Can I do this using any way, and if not can any one help me solving this kind of issue, and to know that I know how to solve it but I don't want to rewrite the same field in the create and in the update mutations for the same model or type.

This is a sample of my code:

import graphene
from graphene import relay

from BoD.models import Meeting
from BoD.types.meeting import MeetingType


class CreateMeeting(relay.ClientIDMutation):
    """Mutation to create a new meeting."""

    class Input:
        created_by_id = graphene.Int(required=True)
        subject = graphene.String(required=True)
        location = graphene.String(required=True)
        date = graphene.DateTime(required=True, datetime_input=graphene.DateTime(required=True))
        start_time = graphene.Time(required=True)
        end_time = graphene.Time(required=True)

    meeting = graphene.Field(MeetingType)

    @classmethod
    def mutate_and_get_payload(cls, root, info, **input):
        """Create a new meeting."""
        meeting = Meeting.objects.create(**input)
        return CreateMeeting(meeting=meeting)


class UpdateMeeting(CreateMeeting):
    """Mutation to update a meeting."""

    class Input(CreateMeeting.Input):
        id = graphene.Int(required=True)


class MeetingMutate:
    class Meta:
        abstract = True
        created_by_id = graphene.Int(required=True)
        subject = graphene.String(required=True)
        location = graphene.String(required=True)
        date = graphene.DateTime(required=True, datetime_input=graphene.DateTime(required=True))
        start_time = graphene.Time(required=True)
        end_time = graphene.Time(required=True)


class CreateMeeting(relay.ClientIDMutation):
    """Mutation to create a new meeting."""

    class Input(MeetingMutate.Meta):
        pass

    meeting = graphene.Field(MeetingType)

    @classmethod
    def mutate_and_get_payload(cls, root, info, **input):
        """Create a new meeting."""
        meeting = Meeting.objects.create(**input)
        return CreateMeeting(meeting=meeting)


class UpdateMeeting(CreateMeeting):
    """Mutation to update a meeting."""

    class Input(MeetingMutate.Meta):
        id = graphene.Int(required=True)

    meeting = graphene.Field(MeetingType)

    @classmethod
    def mutate_and_get_payload(cls, root, info, **input):
        """Update a meeting."""
        meeting = Meeting.objects.get(pk=input['id'])
        meeting.update(**input)
        meeting.save()
        return UpdateMeeting(meeting=meeting)

    meeting = graphene.Field(MeetingType)

    @classmethod
    def mutate_and_get_payload(cls, root, info, **input):
        """Update a meeting."""
        meeting = Meeting.objects.get(pk=input['id'])
        meeting.update(**input)
        meeting.save()
        return UpdateMeeting(meeting=meeting)

But this code gives me this error:

TypeError at /graphql
Cannot create a consistent method resolution
order (MRO) for bases InputObjectType, Input

Solution

I have created this code to solve my problem until anyone helps me with the issue.

The code looks like this:

import graphene
from graphene import relay

from BoD.models import Meeting
from BoD.types.meeting import MeetingType


class MeetingInput(graphene.InputObjectType):
    created_by_id = graphene.Int(required=True)
    subject = graphene.String(required=True)
    location = graphene.String(required=True)
    date = graphene.DateTime(required=True)
    start_time = graphene.Time(required=True)
    end_time = graphene.Time(required=True)


class CreateMeeting(relay.ClientIDMutation):
    """Mutation to create a new meeting."""

    class Input:
        input = MeetingInput(required=True)

    meeting = graphene.Field(MeetingType)

    @classmethod
    def mutate_and_get_payload(cls, root, info, input):
        """Create a new meeting."""
        meeting = Meeting.objects.create(**input)
        return CreateMeeting(meeting=meeting)


class UpdateMeeting(relay.ClientIDMutation):
    """Mutation to update a meeting."""

    class Input:
        input = MeetingInput(required=True)
        id = graphene.Int(required=True)

    meeting = graphene.Field(MeetingType)

    @classmethod
    def mutate_and_get_payload(cls, root, info, input):
        """Update a meeting."""
        meeting = Meeting.objects.get(id=input.id)
        meeting.update(**input)
        meeting.save()
        return UpdateMeeting(meeting=meeting)

Answered By - Dhiaa Shalabi

Answer Checked By - David Goodson (PHPFixing Volunteer)