I18n.available_locales is mutated

[seger-finstreet]

Describe the bug

When using the i18n adapter as a message backend, I18n.available_locales gets mutated and English is added as an available locale.

dry-schema looks into it's load paths, finds the English locale file it ships with, and adds English as available locale to I18n.

This is a rather surprising side effect I did not expect. In our application, I18n.available_locales is the source of truth for which locales our application supports. We configure this very explicitly in a Rails initializer
and we rely on it to stay as it is. A gem should not simply alter the available locales. At least not without any warnings.

To Reproduce

• Use i18n as a message backend
• Configure English to be excluded from I18n.available_locales in a (Rails) initializer
• Create a schema with dry-schema
• I18n.available_locales now includes :en

Expected behavior

I18n.available_locales is not altered.

My environment

• Ruby 3.4.2
• dry-schema 1.13.4

Workaround

Right now, my workaround is to empty the dry-schema messages load path if the application is not supposed to support English.

Source of the issue

lib/dry/schema/messages/i18n.rb:124