Migration error when using default currency that is not USD

[stephenmoloney]

What I'm trying to achieve

When moving to new dockerhub saleor image 558de3985903133660e97d8a436b374c405a2fa1,
https://hub.docker.com/r/mirumee/saleor/tags/

Installation of saleor using a default currency that is not USD. In this case, DEFAULT_CURRENCY
was set to GBP

Steps to reproduce the problem

python3 manage.py migrate on a clean installation

What I expected to happen

I expected the migration to end successfully like previous saleor versions when DEFAULT_CURRENCY = GBP

Issue was resolved when DEFAULT_CURRENCY = USD

Error message

Operations to perform:
  Apply all migrations: account, auth, checkout, contenttypes, discount, django_celery_results, django_prices_openexchangerates, django_prices_vatlayer, impersonate, menu, order, page, payment, product, sessions, shipping, site, sites, social_django
Running migrations:
Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.6/site-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/base.py", line 316, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/base.py", line 353, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 203, in handle
    fake_initial=fake_initial,
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/executor.py", line 117, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/executor.py", line 147, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/migration.py", line 124, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/operations/fields.py", line 216, in database_forwards
    schema_editor.alter_field(from_model, from_field, to_field)
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 523, in alter_field
    old_db_params, new_db_params, strict)
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/postgresql/schema.py", line 122, in _alter_field
    new_db_params, strict,
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 627, in _alter_field
    new_default = self.effective_default(new_field)
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 218, in effective_default
    default = field.get_default()
  File "/usr/local/lib/python3.6/site-packages/django_prices/models.py", line 59, in get_default
    return self.to_python(default)
  File "/usr/local/lib/python3.6/site-packages/django_prices/models.py", line 28, in to_python
    value.currency, self.currency))
ValueError: Invalid currency: 'GBP' (expected 'USD')

System information

Operating system: docker container
Browser: N/A

[chrisfranklin]

Did you find a solution for this?

[stephenmoloney]

@chrisfranklin Not yet, I'm a bit busy for about another week. I will look into this more in about a week. The same error does not occur on older versions of saleor.

[stephenmoloney]

@Pacu2
Have you encountered this issue?

It could be due to some changes in this commit:
c629988#diff-703f34f1c35686322145c8a0ae145792

I'm not really able to assess this easily.

[fredagsfys]

This is making our deployments painful as we need to set it to USD upon migration, then shift to SEK.
Is there a work-around/monkey-patch until fixed?

[adonig]

I managed to fix this by replacing all occurrences of currency='USD' with currency='EUR' in all existing migrations. Thereafter python manage.py migrate successfully went through.

Because I read in another issue that it is necessary, I cascadingly truncated the order_order table before. So if the trick above doesn't work, try that (warning: it deletes all existing orders).

[Pacu2]

How about replacing “USD” in migrations with “settings.DEFAULT_CURRENCY”? haven’t tried but should work tho

[NyanKiyoshi]

Well, if I understand correctly, the issue occurs when that value gets changed by the user.

Assuming that the user is setting a environment variable, and not directly editing the settings.py file. The workaround would be no to set the environment variable DEFAULT_CURRENCY, so, to keep it to USD when generating migrations and migrating.

But, then, if the store currency is BTC for example, we would need to regenerate migrations because we would have to change the data precision. But in the case of GBP, that's not an issue to makemigrations/ migrate with USD instead.

[Pacu2]

Resolved in #3506