Extend update_fields with translation fields in Model.save()

[andrei-shabanski]

An alternative approach to resolving #682

Override QuerySet._update() to update translation fields if only an original field is passed in save() in argument update_fields

[andrei-shabanski]

@last-partizan Tests for django < 4.2 fail because we don't add the original field in update_field.

Hence the following code updates only title_de field in django 4.2, and both fields title & title_de in django < 4.2

instance, created = models.TestModel.objects.update_or_create(
     pk=obj.pk, defaults={'title_de': 'NEW DE TITLE 2'}
)

Should we update the original field in the code below?

[last-partizan]

Are you sure? Looking at update_or_create which you removed, it doesn't seem to rewrite original key when passing translated key.

But, for the sake of consistency, i think it's fine to update 'title' when passing title_de to the function. But, only when 'de' is the default language. Otherwise it would be unexpected behaviour.

[last-partizan]

4.0 tests are also failing, as you can see. So your original suggestion may be incorrect.

Oh, hevermind, i read it other way. You're correct.

[andrei-shabanski]

The same errors (or behavior) were relevant for the removed implementation of update_or_create. We just didn't have tests to catch them

[andrei-shabanski]

But, for the sake of consistency, i think it's fine to update 'title' when passing title_de to the function. But, only when 'de' is the default language. Otherwise it would be unexpected behaviour.

The current django-modeltranslation version saves the last assigned value to the original field into "title" column even when a secondary language is active currently. Check the sample below

>>> obj = TestModel(title='default')
... with override('en'):
...     obj.title = 'English variant'
...     obj.save()
... 
... TestModel.objects \
...     .rewrite(False) \
...     .filter(pk=obj.pk) \
...     .values('title', 'title_de', 'title_en') \
...     .first()

{
    "title": "English variant",
    "title_de": "default",
    "title_en": "English variant",
}

So "title" might store not only the default translation (-- that looks strange to me).

Should we check the currently active language to determine when the original field (title) must be updated? I mean to update "title" even if "de" isn't default language

[last-partizan]

So "title" might store not only the default translation (-- that looks strange to me).

AFAIK, docs are suggesting "not rely on the original field anymore", becouse it can be incosistent.

If we can make it consistent with minimal changes, then yes, let's do it. But if that would be too much rewriting, we should leave this for separate refactoring - if you want to fix it.

Right now we should focus on solving "Extend update_fields with translation variants", without breaking update_or_create. Maybe we even should exclude "title" from assertions, to get tests to pass.

[andrei-shabanski]

I excluded "title" from the assertion. Not sure I can find the right approach now due to my limited knowledge of the codebase

[last-partizan]

I excluded "title" from the assertion. Not sure I can find the right approach now due to my limited knowledge of the codebase

@andrei-shabanski please, add a note about this in the test.

[last-partizan]

Please reabse it on latest master, CI was broken because latest mariadb was failing to start.