IntegrityError: could not create unique index when adding translation mixins to created objects

[marcosguedes]

Hi, I'm running Wagtail 5.0 and wagtail-localize 1.6 and I'm getting an issue when adding translation to current models

I followed the tutorial up to the part where we translate content. I create a new migration where Wagtail suggests me to create a unique_together constraint. I do so but it still remains.

$ ./manage.py makemigrations
ERRORS:
portfolio.ProjectCategoryName: (wagtailcore.E003) portfolio.ProjectCategoryName is missing a unique_together constraint for the translation key and locale field
        HINT: Add ('translation_key', 'locale') to ProjectCategoryName.Meta.unique_together

+...
+from wagtail.models import TranslatableMixin
+...


-class ProjectCategoryName(Orderable):
+class ProjectCategoryName(Orderable, TranslatableMixin):
    name = models.CharField(max_length=255)

    panels = [
        FieldPanel("name"),
    ]

    class Meta:
        verbose_name = _("Project Category")
        verbose_name_plural = _("Project Categories")
        ordering = ("name",)
+        unique_together = ("translation_key", "locale")

    def __str__(self):
        return self.name

It then asks me for a default. I use the first locale ID

$ ./manage.py makemigrations portfolio
It is impossible to add a non-nullable field 'locale' to projectcategoryname without specifying a default. This is because the database needs something to populate existing rows.
Please select a fix:
 1) Provide a one-off default now (will be set on all existing rows with a null value for this column)
 2) Quit and manually define a default value in models.py.
Select an option: 1
>>> 1

Then it breaks when I'm migrating

django.db.utils.IntegrityError: could not create unique index "portfolio_projectcategor_translation_key_locale_i_77fbe046_uniq"
DETAIL:  Key (translation_key, locale_id)=(cd19e8c3-81be-4da7-8a45-c78cb26c69e1, 1) is duplicated.

Is there something I can do to fix this? Or adding translations requires me to delete everything and start over?

Apologies if this is a newbie question unrelated to the package or it's addressed somewhere in the documentation but it's my first time with Wagtail and my eyes are burning.

Cheers

[zerolab]

@marcosguedes please see https://docs.wagtail.org/en/stable/advanced_topics/i18n.html#making-snippets-with-existing-data-translatable for instructions on how to make models with content translatable

If you have suggestions on how to improve the documentation, please do share and even better, submit a PR

[marcosguedes]

@zerolab many thanks. I believe the issue here was due to being fully guided by wagtail-localize.org. I can submit a PR with a warning in this section pointing to the docs if you believe that's the right approach

[zerolab]

@marcosguedes a warning would most certainly be useful there, thank you