Error whikle making existing fields translatable - model already has a field

I am trying to translate already existing fields on a model class. I got stuck at the very first step, which is subclassing TranslatableModel class in Category class, and adding TranslatedFields wrapper to translate selected model fields. I am following a book ‘Django by Example’ as well as the django-parler instructions on how to do that, however when I run manage.py makemigrations myapp "add_translation_model" I am getting the following error :

File ..../env/lib/python3.5/site-packages/parler/models.py", line 965, in contribute_translations
raise TypeError("The model '{0}' already has a field named '{1}'".format(shared_model.__name__, name))
TypeError: The model 'Category' already has a field named 'name'

before applying django-parler:

# models.py
class Category(models.Model):
    name = models.CharField(max_length=200,
                            db_index=True)
    slug = models.SlugField(max_length=200,
                            unique=True)
    class Meta:
        ordering = ('name',)
        verbose_name = 'category'
        verbose_name_plural = 'categories'

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse('shop:product_list_by_category',
                       args=[self.slug])

after applying django-parler:

# models.py
class Category(TranslatableModel):
    name = models.CharField(max_length=200,
                            db_index=True)
    slug = models.SlugField(max_length=200,
                            unique=True)
    translations = TranslatedFields(
        name = models.CharField(max_length=200,
                                db_index=True),
        slug = models.SlugField(max_length=200,
                                unique=True),
    )
    class Meta:
        # ordering = ('name',)
        verbose_name = 'category'
        verbose_name_plural = 'categories'

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse('shop:product_list_by_category',
                       args=[self.slug])

I am using Django 1.10.

[vglfr]

Same problem, my workaround:

• rename names * to *_t inside translations tuple
• makemigrations
• manually rename *_t back to * in migration files

[stefanw]

It looks like this check:

if not isinstance(shared_field, (models.Field, TranslatedFieldDescriptor)):
    raise TypeError("The model '{0}' already has a field named '{1}'".format(shared_model.__name__, name))

does not work with Django 3.1. getattr(shared_model, name) returns a django.db.models.query_utils.DeferredAttribute and thus fails the test for being a model field. The comment above it seems outdated.

           # Currently not allowing to replace existing model fields with translatable fields.
           # That would be a nice feature addition however.

My work around was:

• prefix existing fields with e.g. _ to create a rename migration
• add translation fields with original field names
• create data migration between prefixed fields and translation model
• remove prefixed fields