[Django] #27419: Model that worked before 1.10 causes "Cannot force an update in save() with no primary key." in 1.10.
Django
no primary key." in 1.10.
-------------------------------------+-------------------------------------
Reporter: Louis- | Owner: nobody
Dominique Dubeau |
Type: Bug | Status: new
Component: Database | Version: 1.10
layer (models, ORM) |
Severity: Normal | Keywords: save model property
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
This problem does not happen prior to Django 1.10. I'm running this on
Python 2.7.12 but I don't think the Python version is an issue. The
following case is distilled form a full-fledged application that has run
fine in production since Django 1.6. Upon upgrading to 1.10, I immediately
got the error reported here.
Consider the following models.py file:
{{{
from __future__ import unicode_literals
from django.db import models
class Foo(models.Model):
a = models.CharField(max_length=10)
b = models.CharField(max_length=10)
parent = models.ForeignKey(
"self", related_name="children", null=True, blank=True)
class Bar(models.Model):
a = models.CharField(max_length=10)
_b = models.CharField(max_length=10, name="b", db_column="b")
parent = models.ForeignKey(
"self", related_name="children", null=True, blank=True)
@property
def b(self):
return self._b
@b.setter
def b(self, val):
print "SETTING B"
# This would make the problem disappear:
# self.__dict__["b"] = val
self._b = val
}}}
And the following tests.py file which is a sibling to models.py above:
{{{
from django.test import TestCase
from .models import *
class TestFoo(TestCase):
def test(self):
parent = Foo(a="parent_a", b="parent_b")
parent.save()
foo = Foo(a="1a", b="1b", parent=parent)
foo.save()
class TestBar(TestCase):
def test(self):
parent = Bar(a="parent_a", b="parent_b")
parent.save()
bar = Bar(a="1a", b="1b", parent=parent)
bar.save()
}}}
Running `./manage.py test` results in:
{{{
$ ./manage.py test
Creating test database for alias 'default'...
SETTING B
SETTING B
E.
======================================================================
ERROR: test (myapp.tests.TestBar)
----------------------------------------------------------------------
Traceback (most recent call last):
File
"/home/ldd/src/django_issues/deferred_fields_in_1.10/issue/myapp/tests.py",
line 19, in test
bar.save()
File "/home/ldd/src/django_issues/deferred_fields_in_1.10/issue-
venv/local/lib/python2.7/site-packages/django/db/models/base.py", line
796, in save
force_update=force_update, update_fields=update_fields)
File "/home/ldd/src/django_issues/deferred_fields_in_1.10/issue-
venv/local/lib/python2.7/site-packages/django/db/models/base.py", line
824, in save_base
updated = self._save_table(raw, cls, force_insert, force_update,
using, update_fields)
File "/home/ldd/src/django_issues/deferred_fields_in_1.10/issue-
venv/local/lib/python2.7/site-packages/django/db/models/base.py", line
880, in _save_table
raise ValueError("Cannot force an update in save() with no primary
key.")
ValueError: Cannot force an update in save() with no primary key.
----------------------------------------------------------------------
Ran 2 tests in 0.002s
FAILED (errors=1)
Destroying test database for alias 'default'...
}}}
If I downgrade to Django 1.9, I get:
{{{
$ ./manage.py test
Creating test database for alias 'default'...
SETTING B
SETTING B
..
----------------------------------------------------------------------
Ran 2 tests in 0.001s
OK
Destroying test database for alias 'default'...
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/27419>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
no primary key." in 1.10.
-------------------------------------+-------------------------------------
Dubeau |
Type: Bug | Status: new
(models, ORM) |
Severity: Normal | Resolution:
Keywords: save model property | Triage Stage:
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* Attachment "models.py" added.
Django
no primary key." in 1.10.
-------------------------------------+-------------------------------------
Dubeau |
Type: Bug | Status: new
(models, ORM) |
Severity: Normal | Resolution:
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* Attachment "tests.py" added.
Django
no primary key." in 1.10.
-------------------------------------+-------------------------------------
Dubeau |
Type: Bug | Status: new
(models, ORM) |
Severity: Normal | Resolution:
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Tim Graham):
It's not obvious that this is a Django bug since you're doing some non-
standard stuff with `setter`. Could you try
[https://docs.djangoproject.com/en/dev/internals/contributing/triaging-
tickets/#bisecting-a-regression bisecting] to find the commit where the
behavior changed? A similar issue was [https://groups.google.com/d/topic
/django-users/lwijFEquQI8/discussion reported on django-users].
--
Ticket URL: <https://code.djangoproject.com/ticket/27419#comment:1>
Django
no primary key." in 1.10.
-------------------------------------+-------------------------------------
Dubeau |
Type: Bug | Status: new
(models, ORM) |
Severity: Normal | Resolution:
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Lucas Moeskops):
The bug seems to be introduced here:
{{{
commit 7f51876f99851fdc3fef63aecdfbcffa199c26b9
Author: Anssi Kääriäinen <anssi.ka...@thl.fi>
Date: Tue Feb 2 11:33:09 2016 +0200
Fixed #26207 -- Replaced dynamic classes with non-data descriptors for
deferred instance loading.
:040000 040000 bc475a97153a13ed83629d19d53f4aff0cb064f6
0343367b1a537396c570ab15d6c8495b70e4700c M django
:040000 040000 439540406e70c8b9ef43db729dbec4cb473e7ee0
a4775e8e1bdb64eb549d000a9e6efcd58868b86e M docs
:040000 040000 cc14ca4b983abe3a6aa6f0f82b329375e7259df7
a9e3feb171711fe29098f1f3d2370f878f936c04 M tests
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/27419#comment:2>
Django
no primary key." in 1.10.
-------------------------------------+-------------------------------------
Dubeau |
Component: Database layer | Version: 1.10
(models, ORM) |
Keywords: save model property | Triage Stage:
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* status: new => closed
* resolution: => needsinfo
Comment:
It seems to have to do with specifying a different name attribute ('b') on
the field than the field name itself ('_b'). If I omit that attribute, the
tests pass. I can't find documentation for passing a different `name`
attribute. Maybe this is incorrect?
--
Ticket URL: <https://code.djangoproject.com/ticket/27419#comment:3>