Is my DRF create function losing data before saving?

I have the following DRF viewset:

class RecordViewSet(ModelViewSet):
    queryset = Record.objects.all()
    serializer_class = RecordSerializer
    filterset_fields = ['task', 'workday']
    
    def get_workday(self, request):
        date = get_date_from_calendar_string(request.data['date'])
        obj, _ = Workday.objects.get_or_create(user=request.user, date=date)
        return obj.id
    
    def create(self, request):
        request.data['workday'] = self.get_workday(request)
        print(request.data)
        return super().create(request)

The create() method is failing on a not-null constraint:

django.db.utils.IntegrityError: null value in column "task_id" violates not-null constraint
DETAIL:  Failing row contains (159, Added via task panel., 0, 0, 0, null, t, f, null, 98).

However, the print statement in create() shows that the data present in the submission:

{'minutes_planned': 5, 'description': 'Added via task panel.', 'minutes_worked': 5, 'task': 148, 'workday': 98}

I am not seeing the pk for task (148) in the error statement for some reason, indicating to me that it is getting dropped somewhere. I am not using any signals, or overriding save() in the model. What else could be causing this problem? I’ve just started using DRF, so it might be something obvious.

=====

This is the model:

class Record(models.Model):
    task = models.ForeignKey(Task, on_delete=models.CASCADE, related_name='records')
    workday = models.ForeignKey(Workday, on_delete=models.CASCADE, related_name='records')
    description = models.CharField(max_length=128, blank=True, null=True)
    minutes_planned = models.IntegerField(default=0)
    minutes_worked = models.IntegerField(default=0)
    minutes_worked_store = models.IntegerField(default=0)
    user_generated = models.BooleanField(default=True)
    completed = models.BooleanField(default=False)

and the serializer:

class RecordSerializer(serializers.ModelSerializer):
    task = TaskSerializer(read_only=True)

    class Meta:
        model = Record
        fields = ['id', 'workday', 'description', 'completed', 'task', 'minutes_worked', 'minutes_planned']

>Solution :

Your TaskSerializer is read_only for the RecordSerializer which does not allow writing that field and therefor will be ignored on create.

Change your code to the following should work

class RecordSerializer(serializers.ModelSerializer):
    task = TaskSerializer(read_only=True)
    task_id = serializers.PrimaryKeyRelatedField(queryset=models.Task.objects.all(), write_only=True)

https://www.django-rest-framework.org/api-guide/relations/#primarykeyrelatedfield