#32263: squashmigrations produces incorrect result when a RenameModel operation
is
performed on a ForeignKey target
--------------------------------------------+------------------------
Reporter: InvalidInterrupt | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 3.1
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 |
--------------------------------------------+------------------------
Given a list of operations:
{{{
operations = [
migrations.CreateModel(
name="Author",
fields=[
("id",
models.AutoField(auto_created=True, primary_key=True,
serialize=False,
verbose_name="ID")),
]
),
migrations.CreateModel(
name="Book",
fields=[
("id",
models.AutoField(auto_created=True, primary_key=True,
serialize=False,
verbose_name="ID")),
("author",
models.ForeignKey(on_delete=models.deletion.PROTECT,
to="testapp.Author")),
]
),
migrations.RenameModel("Author", "Person"),
migrations.AddField(model_name="person",
name="birthdate",
field=models.DateField()),
]
}}}
squashmigrations produces the result:
{{{
operations = [
migrations.CreateModel(
name='Book',
fields=[
('id', models.AutoField(auto_created=True,
primary_key=True, serialize=False, verbose_name='ID')),
('author',
models.ForeignKey(on_delete=django.db.models.deletion.PROTECT,
to='testapp.author')),
],
),
migrations.CreateModel(
name='Person',
fields=[
('id', models.AutoField(auto_created=True,
primary_key=True, serialize=False, verbose_name='ID')),
('birthdate', models.DateField()),
],
),
]
}}}
There are two apparent problems with the result:
* The model with the `ForeignKey` field is created before the target of
the `ForeignKey`
* The `to` parameter of the `ForeignKey` is not updated with the new model
name
I believe this is caused by `CreateModel.reduce()` allowing optimization
though operations that reference models which the model being created has
a relationship to. Similar effects are likely to be caused by other
migration patterns as well (I think Tim Graham may have found one
[https://code.djangoproject.com/ticket/24849#comment:1 here] but as far as
I can tell that's not the problem originally reported in that ticket)
--
Ticket URL: <https://code.djangoproject.com/ticket/32263>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/059.cc343c38afc7174420a0b56be691b788%40djangoproject.com.
