[BUG] Adding djangocms-versioning after updating to djangocms-snippet 5 breaks migrations

[k-kramer]

Hi i had installed djangocms_history.
But its outdatetd.
So i wanted install djangocms_version but i get this Error Message :

django.db.migrations.exceptions.InconsistentMigrationHistory: Migration djangocms_snippet.0010_cms4_grouper_version_data_migration is applied before its dependency djangocms_versioning.0015_version_modified on database 'default'.

So that means snippets were running until 0015

Versions i have installed
Python 3.11.*
Django 4.2.*
Django-cms 4.1.*
...

I nearly spend two days with trying --fake migrations and deleting migrations in the django table. But its more trial and Error.

Is there a way to get a halfway clean (migration) structure again or remigrate again ?

[fsbraun]

Try the following process:

• Removing djangocms-versioning from installed apps
• Run./manage migrate djangocms_snippet 0008
• Add djangocms-versioning back to installed apps
• Run ./manage migrate.

Let me know if this helped.

[k-kramer]

Thank you for the quick response.

i cant do the step - i'm getting this error now - probably because djangocms_versioning is not the settings.py

File "/home/kramer/envs/web_django/lib/python3.11/site-packages/djangocms_snippet/admin.py", line 25, in <module>
    from djangocms_versioning.admin import (
  File "/home/kramer/envs/web_django/lib/python3.11/site-packages/djangocms_versioning/admin.py", line 42, in <module>
    from .emails import notify_version_author_version_unlocked
  File "/home/kramer/envs/web_django/lib/python3.11/site-packages/djangocms_versioning/emails.py", line 10, in <module>
    from djangocms_versioning import models
  File "/home/kramer/envs/web_django/lib/python3.11/site-packages/djangocms_versioning/models.py", line 88, in <module>
    class Version(models.Model):
  File "/home/kramer/envs/web_django/lib/python3.11/site-packages/django/db/models/base.py", line 134, in __new__
    raise RuntimeError(
RuntimeError: Model class djangocms_versioning.models.Version doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS.

it seems to be a deadlock somehow ...

But i see what you want to unapply the migrations

I addition try to unapply from the source environment cms 3.11.*

Django 4.2.*
django-cms==3.11.*
djangocms_history...
djangocms-snippet==5.0.0

versioning NOT INSTALLED

its unapplying until

  Target specific migration: 0008_auto_change_name, from djangocms_snippet
Running migrations:
  Rendering model states... DONE
  Unapplying djangocms_snippet.0015_alter_snippetgrouper_id... OK
  Unapplying djangocms_snippet.0014_merge_20240519_2117... OK
  Unapplying djangocms_snippet.0010_alter_snippet_id... OK
  Unapplying djangocms_snippet.0009_alter_snippetptr_cmsplugin_ptr... OK
  Unapplying djangocms_snippet.0013_snippet_site... OK
  Unapplying djangocms_snippet.0012_auto_20210915_0721...Traceback (most recent call last):
  File "/home/kramer/envs/web_django/lib/python3.11/site-packages/django/db/backends/utils.py", line 87, in _execute
    return self.cursor.execute(sql)
           ^^^^^^^^^^^^^^^^^^^^^^^^
psycopg2.errors.NotNullViolation: FEHLER:  Spalte »snippet_id« von Relation »djangocms_snippet_snippetptr« enthält NULL-Werte

Ah sorry its in german the last output.

[k-kramer]

@fsbraun
i recreated a clean project with django-cms 3.11 to to recreate this issue / bug.
https://github.com/k-kramer/djangocms-snippet-bug
If you or anyone quickly follow the steps as described in the readme file.
The error message appears as expectet.
So General the problem is
django-snippets==5.0.0 # all migrations to 0015
django-cms==3.11.*
could be installed without djangocms-versoning

But
django-snippets==5.0.0
django-cms==4.1.*
is only possible to install / run with djangocms-versoning

[filipweidemann]

This is hitting us in the face as well. Currently working on a mitigation, I'll let you know if we come up with a working solution.

[filipweidemann]

@k-kramer @fsbraun we opened a PR with a proposed fix. We are currently not sure if this has the intended effect and is free of side-effects.

If you have further questions, we can iterate on our solution. Just ping me or @ms-18. Thank you.

[k-kramer]

@filipweidemann
thank you for the branch / fix - i will try it tomorrow.
as far as i understand the migration code and if we want to integrate djangocms_versions
we have to rerun this single migration or code working code snippet https://github.com/django-cms/djangocms-snippet/blob/master/src/djangocms_snippet/migrations/0010_cms4_grouper_version_data_migration.py
This Migration is creating initial version objects of snippets. I will try.

[fsbraun]

I fear the migration process is flawed. I am thinking of replacing come of the migrations by noops and providing a different way to create version objects.

[filipweidemann]

@fsbraun wouldn't a management command be a fair middle-ground? Anyone who doesn't need versioning on the snippets can just apply the fixed migrations and everyone else has to run the command once after the update.

[fsbraun]

@filipweidemann Yes, indeed. Can I build on your PR and make changes in its branch?

[filipweidemann]

@fsbraun of course! :)

[filipweidemann]

@fsbraun do you need an invitation to the project or do you work on a seperate PR? I could invite you to the fork so you can work directly on the master branch.

[fsbraun]

@filipweidemann No worries, I can create a separate branch. There's the option to allow for maintainers to make changes to a PR (but you did not use this :-) ). I'll keep you posted.