#23556: Allow migrations to depend on a migration only part of a squashed
migration
-----------------------------+---------------------------------------
Reporter: Markush2010 | Owner: Markush2010
Type: Bug | Status: new
Component: Migrations | Version: master
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-----------------------------+---------------------------------------
Changes (by carljm):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
* type: Uncategorized => Bug
* stage: Unreviewed => Accepted
Old description:
> If a migration depends on another migration that is part of a squashed
> migration (e.g. `6_auto` depends on `5_auto` which is part of
> `3_squashed_5`) this leads to a `KeyError`:
>
> {{{#!python
> Traceback (most recent call last):
> File "/home/markus/Coding/django/django/test/utils.py", line 216, in
> inner
> return test_func(*args, **kwargs)
> File "/home/markus/Coding/django/tests/migrations/test_loader.py", line
> 263, in test_loading_squashed_complex2
> loader.build_graph()
> File "/home/markus/Coding/django/django/db/migrations/loader.py", line
> 233, in build_graph
> self.graph.add_dependency(migration, key, parent)
> File "/home/markus/Coding/django/django/db/migrations/graph.py", line
> 42, in add_dependency
> raise KeyError("Migration %s dependencies reference nonexistent
> parent node %r" % (migration, parent))
> KeyError: "Migration migrations.6_auto dependencies reference nonexistent
> parent node ('migrations', '5_auto')"
> }}}
>
> Thus the whole idea of `squashmigrations` to be able to remove old
> migrations is not really working out since a 3rd party app might depend
> on a specific migration.
>
> I build a testcase:
> https://github.com/Markush2010/django/commit/9a983d4fe66c583858eb370497d0b66227690f79
New description:
If a migration depends on another migration that is part of a squashed
migration (e.g. `6_auto` depends on `5_auto` which is part of
`3_squashed_5`) removing the squashed migration (e.g. `5_auto`) leads to a
`KeyError`:
{{{#!python
Traceback (most recent call last):
File "/home/markus/Coding/django/django/test/utils.py", line 216, in
inner
return test_func(*args, **kwargs)
File "/home/markus/Coding/django/tests/migrations/test_loader.py", line
263, in test_loading_squashed_complex2
loader.build_graph()
File "/home/markus/Coding/django/django/db/migrations/loader.py", line
233, in build_graph
self.graph.add_dependency(migration, key, parent)
File "/home/markus/Coding/django/django/db/migrations/graph.py", line
42, in add_dependency
raise KeyError("Migration %s dependencies reference nonexistent parent
node %r" % (migration, parent))
KeyError: "Migration migrations.6_auto dependencies reference nonexistent
parent node ('migrations', '5_auto')"
}}}
Thus the whole idea of `squashmigrations` to be able to eventually remove
old migrations is not really working out since a 3rd party app might
depend on a specific migration.
I build a testcase:
https://github.com/Markush2010/django/commit/9a983d4fe66c583858eb370497d0b66227690f79
--
--
Ticket URL: <https://code.djangoproject.com/ticket/23556#comment:1>
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 django-updates+unsubscr...@googlegroups.com.
To post to this group, send email to django-updates@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/069.cac5ad8f61b67e755acdc05ca47889a8%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
