#28803: When renaming foreign key indexes don't get renamed which breaks next
migrations
-----------------------------------------+------------------------
Reporter: Jacek Bzdak | Owner: nobody
Type: Uncategorized | Status: new
Component: Migrations | Version: 1.11
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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Here is what I did. I have following models:
{{{
class ReferencedModel(models.Model):
pass
class SecondReferencedModel(models.Model):
pass
class ReferenceeModel(models.Model):
child = models.ForeignKey(ReferencedModel, default=None,
on_delete=models.CASCADE)
}}}
I want to swichch ``ReferenceeModel.child`` to ``SecondReferencedModel``.
I want to do it by:
1) Renaming ``ReferenceeModel.child_old``
2) Adding ``ReferenceeModel.child`` that points to proper model
3) Some RunPython magic
4) Delete ``ReferenceeModel.child_old``
Actual bug:
{{{
class Migration(migrations.Migration):
initial = True
dependencies = [
]
operations = [
migrations.CreateModel(
name='ReferencedModel',
fields=[
('id', models.AutoField(auto_created=True,
primary_key=True, serialize=False, verbose_name='ID')),
],
),
migrations.CreateModel(
name='SecondReferencedModel',
fields=[
('id', models.AutoField(auto_created=True,
primary_key=True, serialize=False, verbose_name='ID')),
],
),
migrations.CreateModel(
name='ReferenceeModel',
fields=[
('id', models.AutoField(auto_created=True,
primary_key=True, serialize=False, verbose_name='ID')),
('child',
models.ForeignKey(on_delete=django.db.models.deletion.CASCADE,
to='index_error.ReferencedModel')),
],
),
]
class Migration(migrations.Migration):
dependencies = [
('index_error', '0001_initial'),
]
operations = [
migrations.RenameField(
model_name='referenceemodel',
old_name='child',
new_name='child_copy',
),
]
class Migration(migrations.Migration):
dependencies = [
('index_error', '0002_auto_20171116_1505'),
]
operations = [
migrations.AddField(
model_name='referenceemodel',
name='child',
field=models.ForeignKey(default=None,
on_delete=django.db.models.deletion.CASCADE,
to='index_error.SecondReferencedModel'),
),
]
}}}
Third migration explodes with following error:
{{{django.db.utils.ProgrammingError: relation
"index_error_referenceemodel_child_id_59ba6fc6" already exist }}}
Which is due to the
1) Field `` child = models.ForeignKey(ReferencedModel, ...)`` generates
postgresql index named ``index_error_referenceemodel_child_id_59ba6fc6``
2) RenameField operation doesn't update index name (but changes field
name)
3) When I try to create new field index names clash.
My setup:
* Django 1.11 (also broken in 2.0)
* postgresql database
--
Ticket URL: <https://code.djangoproject.com/ticket/28803>
Django <https://code.djangoproject.com/>
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