On 21/12/2015 6:10 PM, James Schneider wrote:
I have just been digging into django.forms.models.py <http://django.forms.models.py> to debug my own code and found something which confuses me in both 1.8 and 1.9django.forms.models.BaseModelFormSet.save_existing_objects() puts objects (child model instances) into the BaseModelFormSet.deleted_objects list whether they are deleted or not. Here is the 1.9 code (no need to show 1.8 because they are both more or less the same) 741 def save_existing_objects(self, commit=True): 742 self.changed_objects = [] 743 self.deleted_objects = [] 744 if not self.initial_forms: 745 return [] 746 747 saved_instances = [] 748 forms_to_delete = self.deleted_forms 749 for form in self.initial_forms: 750 obj = form.instance 751 if form in forms_to_delete: 752 # If the pk is None, it means that the object can't be 753 # deleted again. Possible reason for this is that the 754 # object was already deleted from the DB. Refs #14877. 755 if obj.pk <http://obj.pk> is None: 756 continue 757 self.deleted_objects.append(obj) 758 self.delete_existing(obj, commit=commit) 759 elif form.has_changed(): 760 self.changed_objects.append((obj, form.changed_data)) 761 saved_instances.append(self.save_existing(form, obj, commit=commit)) 762 if not commit: 763 self.saved_forms.append(form) 764 return saved_instances Line 758 will fail and the object will not be deleted if commit == False but line 757 has already added the object to a list. Is this intended? Wouldn't L757 only get executed if L751 has already determined that the particular object/form is supposed to be deleted, meaning that self.deleted_objects would only contain objects/forms that were supposed to be deleted?
That is true. However, if commit was False that object wouldn't be deleted but it would still appear in the self.deleted_objects list. My concern - or more accurately lack of understanding - is that the object would remain in existence AND appear in the deleted list. This was precisely what happened in my project and which I was trying to debug.
The symptom in the Admin was a checked box for deleting a child record which stubbornly stayed there despite the Admin reporting a successful save.
Mike
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