Thread issue when calling translate with Fallbacks

[bcornellCC]

What I tried to do

I ran a rails application in a threaded environment with calls to I18n.t where there is no translation in my locale but there is a translation in a fallback locale

What I expected to happen

I expected I18n.t to return the translation string from the fallback locale

What actually happened

Occasionally and unpredictably I received a missing translation error

Versions of i18n, rails, and anything else you think is necessary

i18n version 0.8.1. I was previously using version 0.7.0 and did not experience this issue.

---

This code reproduces the issue fairly reliably with i18n 0.8.1 but works properly with 0.7.0

require 'i18n'
class Backend < I18n::Backend::Simple
  include I18n::Backend::Fallbacks
end
I18n.backend = Backend.new
I18n.backend.store_translations(:en, {'foo' => 'bar'})
I18n.backend.store_translations(:de , { 'baz' => 'buz'})

threads = []
100.times do
  threads << Thread.new do
    100.times do
      I18n.t('foo', raise: true, locale: :de)
    end
  end
end
threads.each &:join