#23790: Possible bad interaction between migration dependencies and relabeling
apps
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Reporter: aaugustin | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: 1.7
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
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Changes (by MarkusH):
* cc: info+coding@… (added)
Old description:
> As far as I can tell, in migrations, `dependencies` is a list of
> `(app_label, migration_name)`.
>
> I'm wondering what happens if one relabels an application with
> `AppConfig.label`. How can migrations handle this case?
>
> (I haven't tried to create such a problem. I'm just making a note before
> I forget.)
New description:
As far as I can tell, in migrations, `dependencies` is a list of
`(app_label, migration_name)`.
I'm wondering what happens if one relabels an application with
`AppConfig.label`. How can migrations handle this case?
(I haven't tried to create such a problem. I'm just making a note before I
forget.)
The only way I can think of is using the `appconfig.name` attribute
instead of `appconfig.label`. But that's hard to find a smooth migration
path.
--
Comment:
It partially works. If there are no migrations for an app yet, all
migrations will be created with the changed label in the dependencies and
all places it's being referenced. But as soon as you already have existing
migrations and then change the label of an app, the `makemigrations`
command blows up with:
{{{#!python
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/home/markus/Coding/django/django/core/management/__init__.py",
line 338, in execute_from_command_line
utility.execute()
File "/home/markus/Coding/django/django/core/management/__init__.py",
line 330, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/markus/Coding/django/django/core/management/base.py", line
390, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/markus/Coding/django/django/core/management/base.py", line
442, in execute
output = self.handle(*args, **options)
File
"/home/markus/Coding/django/django/core/management/commands/makemigrations.py",
line 58, in handle
loader = MigrationLoader(None, ignore_no_migrations=True)
File "/home/markus/Coding/django/django/db/migrations/loader.py", line
48, in __init__
self.build_graph()
File "/home/markus/Coding/django/django/db/migrations/loader.py", line
295, in build_graph
_reraise_missing_dependency(migration, parent, e)
File "/home/markus/Coding/django/django/db/migrations/loader.py", line
265, in _reraise_missing_dependency
raise exc
File "/home/markus/Coding/django/django/db/migrations/loader.py", line
291, in build_graph
self.graph.add_dependency(migration, key, parent)
File "/home/markus/Coding/django/django/db/migrations/graph.py", line
47, in add_dependency
parent
django.db.migrations.graph.NodeNotFoundError: Migration testapp.0002_proxy
dependencies reference nonexistent parent node ('otherapp',
'0001_initial')
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/23790#comment:1>
Django <https://code.djangoproject.com/>
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