'NoneType' object has no attribute 'get_all_fields' parler

Jan. 5, 2019, 5:32 a.m.

If you create your own migration to add fields that must be translatable, you get error:

'NoneType' object has no attribute 'get_all_fields'

1 case. Update parler

In newer versions of parler, this error has been fixed, so it’s enough to upgrade the package.

2 case. Add TranslatableModelMixin in base class of model

Just addMyModel.__bases__ = (models.Model, TranslatableModelMixin) after declaration of MyModel.

For clarity, take an example from the documentation and add the necessary line:

from django.db import migrations
from django.conf import settings
from django.core.exceptions import ObjectDoesNotExist

def forwards_func(apps, schema_editor):
    MyModel = apps.get_model('myapp', 'MyModel')
    MyModel.__bases__ = (models.Model, TranslatableModelMixin)
    MyModelTranslation = apps.get_model('myapp', 'MyModelTranslation')

    for object in MyModel.objects.all():

def backwards_func(apps, schema_editor):
    MyModel = apps.get_model('myapp', 'MyModel')
    MyModelTranslation = apps.get_model('myapp', 'MyModelTranslation')

    for object in MyModel.objects.all():
        translation = _get_translation(object, MyModelTranslation)
        object.name = translation.name
        object.save()   # Note this only calls Model.save()

def _get_translation(object, MyModelTranslation):
    translations = MyModelTranslation.objects.filter(master_id=object.pk)
        # Try default translation
        return translations.get(language_code=settings.LANGUAGE_CODE)
    except ObjectDoesNotExist:
            # Try default language
            return translations.get(language_code=settings.PARLER_DEFAULT_LANGUAGE_CODE)
        except ObjectDoesNotExist:
            # Maybe the object was translated only in a specific language?
            # Hope there is a single translation
            return translations.get()

class Migration(migrations.Migration):

    dependencies = [
        ('yourappname', '0001_initial'),

    operations = [
        migrations.RunPython(forwards_func, backwards_func),

The fact is that the migration requires the get_all_fields function, which is available in the TranslatableModelMixin mixin when we inherit our model from TranslatableModel. But when migrating from the base (inherited) classes, only models.Model is used, which is why you need to add TranslatableModelMixin manually.

You can read more about this problem from the comment on the github: https://github.com/django-parler/django-parler/issues/157#issuecomment-386902848.

Rate this article

0 from 5 (total 0 ratings)

You can send feedback, suggestions or comments on this article using this form:

Fields marked by star ( * ) is required.

Thank you for yor feedback!

After clicking the "Send" button, your message will be delivered to me on the mail.

Author of Article

Artem Maltsev

Web-developer, having the knowlenge of programming language - Python, framework - Django, content management system - Django CMS, platform of e-commerce site - Django Shop and many other applications, using this technologies.

The right to use content on this page https://vivazzi.pro/it/no-attribute-get_all_fields/:

Permission is granted to copy an content with its author and reference to the original without using the parameter rel="nofollow" in tag <a>. Usage:

Author of Article: Artem Maltsev
Link to article: <a href="https://vivazzi.pro/it/no-attribute-get_all_fields/">https://vivazzi.pro/it/no-attribute-get_all_fields/</a>

More: Terms of site usage

Comments: 0

You can leave a comment as an unregistered user.

But if you sing up, you can:

  • receive notifications
  • view your comments
  • be able to use all the functions of the developed services

To comment in one's own name you should log in or sign up on Vuspace website


There is no search on this site, so I offer to use usual search engine, for example, Google, adding "vivazzi" after your request.

Try it

Select currency for displaying monetary values