# Caveats

## Accessing Translated Fields Outside Views

Since the modeltranslation mechanism relies on the current language as it is returned by the `get_language` function care must be taken when accessing translated fields outside a view function.

Within a view function the language is set by Django based on a flexible model described at How Django discovers language preference which is normally used only by Django’s static translation system.

When a translated field is accessed in a view function or in a template, it uses the `django.utils.translation.get_language` function to determine the current language and return the appropriate value.

Outside a view (or a template), i.e. in normal Python code, a call to the `get_language` function still returns a value, but it might not what you expect. Since no request is involved, Django’s machinery for discovering the user’s preferred language is not activated. For this reason modeltranslation adds a thin wrapper (`modeltranslation.utils.get_language`) around the function which guarantees that the returned language is listed in the `LANGUAGES` setting.

The unittests use the `django.utils.translation.trans_real` functions to activate and deactive a specific language outside a view function.

## Using in combination with `django-audit-log`

`django-audit-log` is a package that allows you to track changes to your model instances (documentation). As `django-audit-log` behind the scenes automatically creates “shadow” models for your tracked models, you have to remember to register these shadow models for translation as well as your regular models. Here’s an example:

    from modeltranslation.translator import register, TranslationOptions

    from my_app import models

    @register(models.MyModel)
    @register(models.MyModel.audit_log.model)
    class MyModelTranslationOptions(TranslationOptions):
        """Translation options for MyModel."""

        fields = (
            'text',
            'title',
        )

If you forget to register the shadow models, you will get an error like:

    TypeError: 'text_es' is an invalid keyword argument for this function

## Using in combination with `django-rest-framework`

When creating a new viewset , make sure to override `get_queryset` method, using `queryset` as a property won’t work because it is being evaluated once, before any language was set.

## Translating `ManyToManyField` fields

Translated `ManyToManyField` fields do not support fallbacks. This is because the field descriptor returns a `Manager` when accessed. If falbacks were enabled we could find ourselves using the manager of a different language than the current one without realizing it. This can lead to using the `.set()` method on the wrong language. Due to this behavior the fallbacks on M2M fields have been disabled.