Opened 4 years ago
Closed 4 years ago
#32625 closed Uncategorized (invalid)
JSONField with callable default reports ModelForm.has_changed() when it hasn't
Reported by: | Stuart Kelly | Owned by: | nobody |
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Component: | Forms | Version: | 3.2 |
Severity: | Normal | Keywords: | |
Cc: | Triage Stage: | Unreviewed | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
The issue is similar to this bug that has been fixed: https://code.djangoproject.com/ticket/24428 however isn't due to coercion
test case to reproduce (in a new django project/app)
from django.db import models from django.forms import ModelForm class Vehicle(models.Model): modifications = models.JSONField(default=list, blank=True, null=True) class VehicleForm(ModelForm): class Meta: model = Vehicle fields = ("modifications", ) def test_vehicle_form(): vehicle = Vehicle.objects.create() assert vehicle.modifications == [] data = {"modifications": "[]"} form = VehicleForm(data, instance=vehicle) assert form.is_valid() assert not form.has_changed()
I would expect that test to pass, but it doesn't. I'm not sure exactly where the error lies, but I have discovered the following:
field.show_hidden_initial == True field.to_python(hidden_widget.value_from_datadict(self.data, self.files, initial_prefixed_name)) == None
which then fails the check in field.has_changed
initial_value = initial if initial is not None else '' data_value = data if data is not None else '' return initial_value != data_value
because data == []
Change History (1)
comment:1 by , 4 years ago
Component: | Uncategorized → Forms |
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Resolution: | → invalid |
Status: | new → closed |
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Fields with callable defaults use
show_hidden_initial
(renders a hidden widget with initial value after the widget), that's why you need to pass initial data to forms, e.g.