with_locale raises an exception if the current locale is not an available locale

[bensheldon]

I'm a gem/Rails engine author that is using with_locale to step as lightly as possible within the parent Rails application. I've found an unexpected problem: 18n.with_locale will raise an exception if the current locale is not an available locale and available locales are enforced. (bensheldon/good_job#549). Thank you for the help!

An alternative way to describe this problem is: I18n's locale/default_locale can be initialized with invalid/unavailable values (I'm not sure if this is originating with this gem or with Rails, but it results in I18n to be in what appears to be an invalid state).

[1] pry(main)> I18n.available_locales
=> [:nl, :fr]
[2] pry(main)> I18n.default_locale
=> :en
[3] pry(main)> I18n.locale
=> :en
[4] pry(main)> I18n.with_locale(:fr) { puts "temporary locale is #{I18n.locale}" }
temporary locale is fr
I18n::InvalidLocale: :en is not a valid locale
from /Users/bensheldon/.rbenv/versions/3.0.3/lib/ruby/gems/3.0.0/gems/i18n-1.10.0/lib/i18n.rb:357:in `enforce_available_locales!'

The exceptions is raised within line 330 of with_locale, when the current locale is reassigned/reset after the block.

i18n/lib/i18n.rb

Lines 321 to 333 in 00fc810

	def with_locale(tmp_locale = nil)
	if tmp_locale == nil
	yield
	else
	current_locale = self.locale
	self.locale = tmp_locale
	begin
	yield
	ensure
	self.locale = current_locale
	end
	end
	end

Potential solutions

• don't allow locale to be initialized in an invalid state in the first place
• have with_locale ignore enforce_available_locales when re-assigning the current locale