Model field translation overrides default langauge for both fields on save

I have a model called ‘Status’ with one field, ‘name’.

I registered the model:

class Status(Model):
    def __str__(self):
        return self.name
    class Meta:
        verbose_name = _('Status')
        verbose_name_plural = _('Statuses')

    name = CharField(verbose_name=_('Status Name'), max_length=100)

@register(Status)
class StatusTranslationOptions(TranslationOptions):
    fields = ('name', )

I registered with and without admin:

class StatusAdmin(TranslationAdmin):
    pass

admin.site.register(Status, StatusAdmin)

I enabled English and Spanish translation and whichever I set my browser configuration to, that’s the language that will override the other.

I have other models in the same app that are similar that don’t override the same way.

[t-mann]

The problem is in the cache as it was mentioned by @kathmandu777 But the cache is not a cache like redis or memcache. The problem sits in the django.db.models.fields.Field.get_col that returns self.cached_col that is actually decorated by @cached_property from django.utils.functional.

The fast workaround that works for me was to create custom register decorator with cleaning field cached properties. I only tested that admin part works correctly thus there still may be some side effects.

Solution allows to fix an issue as quick as possible, specially for projects that are using old versions of the model translations library. I suppose that there is better way to fix this issue in new versions.

"""
Register Decorator Patch
"""

__all__ = [
    'register'
]

# Standard library imports.
import logging

# Related third party imports.
from django.db.models.base import ModelBase

# Local application/library specific imports.


log = logging.getLogger('modeltranslation_patch')


def register(model_or_iterable, raise_exceptions: bool = False, **options):
    """
    Patched decorator to fix issue https://github.com/deschler/django-modeltranslation/issues/593
    Decorator has 1 more parameter `raise_exceptions` that may be used to control exception raising
    in a case if field retrieve from model meta failed
    """
    from modeltranslation.translator import translator, TranslationOptions

    def wrapper(opts_class):
        if not issubclass(opts_class, TranslationOptions):
            raise ValueError('Wrapped class must subclass TranslationOptions.')

        # >>>>>>>>>>> PATCH BEGIN <<<<<<<<<<<<<<
        if isinstance(model_or_iterable, ModelBase):
            models = [model_or_iterable]
        else:
            models = model_or_iterable

        for cls in models:
            for f_name in opts_class.fields:
                try:
                    f_obj = cls._meta.get_field(f_name)
                except Exception as e:
                    if raise_exceptions:
                        raise e
                    log.exception(f'Failed to get field with name `{f_name}` on model {cls.__name__}:\n{e}')
                    continue

                if 'cached_col' in f_obj.__dict__:
                    del f_obj.__dict__['cached_col']

        # >>>>>>>>>>>  PATCH END  <<<<<<<<<<<<<<

        translator.register(models, opts_class, **options)
        return opts_class

    return wrapper

[last-partizan]

I don’t remember any caching (but i just maintainer, not author). Better check source code yourself.