Deleted instances still appear in formfields (Heisenbug?)

I have a model for which I override Django Admin’s formfield_for_foreignkey() like so:

class MyCustomAdmin(CustomSafeDeleteAdmin):

    def get_queryset(self, request):
        qs = super(MyCustomAdmin, self).get_queryset(request)
        return qs.filter(user=request.user)

    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        user= request.user
        if db_field.name == 'foo':
            kwargs['queryset'] = Foo.objects.filter(user=user)
        return super(MyCustomAdmin, self).formfield_for_foreignkey(db_field, request, **kwargs)

The Foo model inherits from SafeDeleteModel, so its default objects manager should be handled by the default SafeDeleteManager.

Problem is I am still seeing deleted Foo instances in formfield ForeignKey dropdowns, but not if I debug Foo.objects.filter(user=user) or Foo.objects.all(), and then if I step through, they don’t appear in the dropdown, hence Heisenbug 😦

Is this releated to the note here on ForeignKey visibility?

Django will stop me from saving the model with a deleted FK, it will give the error Select a valid choice. That choice is not one of the available choices

ATM the only way I can reliably ensure deleted instances don’t appear is to append .exclude(deleted__isnull=False) to all querysets, but this is not desirable, the default manager should ensure they don’t exist?

Using safedelete 0.4.1 with queryset.py from PR #77, Django 1.11.1 and Python 3.6.1 (Note issue happens with or without PR 77 patch)

For extra ref I am overiding some django admin functions so I can split safedelete access in admin between su/staff and ‘lite’ admin users

from safedelete.admin import SafeDeleteAdmin, highlight_deleted

class CustomSafeDeleteAdmin(SafeDeleteAdmin):
    """
    Overriding this convenience class from django-safedelete, as we want:
        - Delete to work 'as in' for non su-staff i.e. User has no idea deleted model instances still exist
        - Allow su/staff to see all instances, deleted or not, and recover them if needs be

    Notes:
        - If su/staff try deleting an already deleted instance, this is a noop
    """

    # override django-safedelete method so deleted instances are hidden from non su/staff
    def get_queryset(self, request):
        qs = super(CustomSafeDeleteAdmin, self).get_queryset(request)
        if request.user.profile.user_can_undelete():
            return qs
        else:
            # assuming the model in question inherits SafeDeleteModel, this will exclude deleted model instances (the default)
            return self.model._default_manager.all()

    def get_list_display(self, request):
        list_display = super(CustomSafeDeleteAdmin, self).get_list_display(request)
        if request.user.profile.user_can_undelete():

            # highlight_deleted overrides the default instance 'Name'
            list_display = list(list_display)
            if 'name' in list_display:
                list_display.remove('name')
            if 'Name' in list_display:
                list_display.remove('Name')
            return [highlight_deleted] + list_display
        else:
            return list_display

    # hide undelete action from admin changelist page actions if user not su/staff
    def get_actions(self, request):
        actions = super(CustomSafeDeleteAdmin, self).get_actions(request)
        if not request.user.profile.user_can_undelete():
            if 'undelete_selected' in actions:
                del actions['undelete_selected']
        return actions

    # hide deleted list_filter from admin changelist page if user not su/staff
    def get_list_filter(self, request):
        list_filter = super(CustomSafeDeleteAdmin, self).get_list_filter(request)
        if request.user.profile.user_can_undelete():
            if isinstance(list_filter, list):
                list_filter = tuple(list_filter)
            return SafeDeleteAdmin.list_filter + list_filter
        else:
            return list_filter

[Gagaro]

Fixed, thanks for the report 👍 .

[Gagaro]

Ok I found it, we need to add iterator to the evaluation_methods.