[Django] #27297: makemigrations creates the same migration again and again (because it fails to compare uppercase to lowercase model names)

Django

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Sep 29, 2016, 10:23:56 AM9/29/16

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#27297: makemigrations creates the same migration again and again (because it fails
to compare uppercase to lowercase model names)
--------------------------------+--------------------
Reporter: Daniel Musketa | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.10
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
--------------------------------+--------------------
Tested and affected Django versions:
- 1.9.6
- 1.10.1

I created a minimal working example to reproduce this
behaviour: https://github.com/vlt/migrations

When you run {{{./manage.py makemigrations}}} it will create
the following migration over and over again:

{{{
Migrations for 'app1':
0003_auto_20160929_1358.py:
- Alter field fk_to_model1 on model2
}}}

The new file {{{0003_auto_20160929_1358.py}}}:

{{{
# -*- coding: utf-8 -*-
# Generated by Django 1.10.1 on 2016-09-29 13:58
from __future__ import unicode_literals

from django.db import migrations, models
import django.db.models.deletion

class Migration(migrations.Migration):

dependencies = [
('app1', '0002_add_model2'),
]

operations = [
migrations.AlterField(
model_name='model2',
name='fk_to_model1',
field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE,
to='app1.Model1'),
),
]
}}}

The #django conversation that led to this ticket:

{{{
11:20:01 vlt | Another question: What stupid thing │
| could I have done that causes │
| makemigrations (v 1.9.6 and 1.10.1) │
| to create the very same AlterField() │
| migration over and over again │
| everytime I run that command? (I’ll │
| try to create an MWE.) │
11:22:10 vlt | $ for _ in {{1..10}}; do ./manage.py │
| makemigrations; done │
11:22:24 vlt | That will produce 10 new migrations │
| files. All looking the same. │
11:22:28 vlt | :-D │
11:37:46 +bmispelon | vlt: what does the migration look │
| like? │
11:50:56 vlt | This is what every of the previous 25 │
| migrations looks like: │
| https://dpaste.de/wS4z (except for │
| the dependencies, of course) │
11:52:13 +bmispelon | vlt: strange. What does the model │
| look like? │
11:54:44 vlt | bmispelon: https://dpaste.de/rWGf │
11:55:21 vlt | bmispelon: Maybe it’s caused by the │
| @property def name() ... weirdness. │
11:58:27 +bmispelon | vlt: I can't reproduce your issue on │
| my machine (I copied the same model │
| you pasted but when I run │
| makemigrations a second time, it │
| doesn't detect new changes) │
11:58:36 +bmispelon | vlt: which version of Python/Django │
| are you using? │
11:59:29 vlt | bmispelon: Created the project on │
| 1.10.1 (3.4), verified the migration │
| zombies also on 1.9.6 (3.4). │
12:00:02 vlt | bmispelon: I tried to reproduce with │
| a smaller model without success. │
12:00:16 vlt | bmispelon: I’ll paste the existing │
| migrations … │
12:01:01 +apollo13 | vlt: name shouldn't affect anything, │
| since it is a normal python variable │
| and not migration related in any way │
12:02:03 +bmispelon | (I still can't reproduce the issue. I │
| tried creating the migration under │
| 1.10 then switching to 1.9 and I │
| still get "no changes detected") │
12:09:44 vlt | bmispelon, apollo13: │
| http://77up.space/migrations.tar │
12:31:30 vlt | bmispelon: Can you reproduce the │
| migration behaviour using the │
| migrations.tar I uploaded? │
12:36:12 +bmispelon | vlt: as a matter of fact, I can │
12:40:47 +bmispelon | vlt: something weird is definitely │
| going on... First I thought it might │
| be because your app is called "name" │
| but I changed that and I still see │
| the same behavior │
12:47:50 +bmispelon | vlt: I don't understand what's going │
| on here, sorry :( │
12:48:16 +bmispelon | I'll see if I can narrow down the │
| reproduction steps later today │
14:18:02 vlt | Hello again. I created a minimal │
| working example for the weird │
| migrations thing: │
| https://github.com/vlt/migrations If │
| you run makemigrations it will create │
| the very same one over and over │
| again. │
14:18:47 +apollo13 | lets see │
14:19:27 +apollo13 | vlt: indeed │
14:28:00 +apollo13 | vlt: oh │
14:29:57 +apollo13 | vlt: seems like a bug, it compares │
| app1.Model1 to app1.model1 -- please │
| open a ticket with that information │
14:30:18 +apollo13 | somehwere a .lower() is missing │
}}}

--
Ticket URL: <https://code.djangoproject.com/ticket/27297>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.

Django

unread,

Sep 29, 2016, 4:18:02 PM9/29/16

to django-...@googlegroups.com

#27297: makemigrations creates the same migration again and again (because it fails
to compare uppercase to lowercase model names)

--------------------------------+--------------------------------------

Reporter: Daniel Musketa | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.10

Severity: Normal | Resolution:
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0

Easy pickings: 0 | UI/UX: 0

--------------------------------+--------------------------------------
Changes (by Daniel Musketa):

* cc: daniel.musketa@… (added)
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0

Old description:

New description:

Tested and affected Django versions:

- 1.7
- 1.8
- 1.9
- 1.9.6
- 1.10.1

The new file {{{0003_auto_20160929_1358.py}}}:

class Migration(migrations.Migration):

--

Comment:

I tested with several other versions and got the following weirdly
unpredictable behaviour:

{{{
(django_1.7) $ for _ in {{1..10}}; do ./manage.py makemigrations; done
Migrations for 'app1':
0003_auto_20160929_2012.py: