Fixes #369 thread issue when calling translate with fallbacks

lib/i18n/backend/fallbacks.rb

@@ -36,11 +36,11 @@ module Fallbacks
       # it is evaluated last after all the fallback locales have been tried.
       def translate(locale, key, options = {})
         return super unless options.fetch(:fallback, true)
-        return super if (@fallback_locked ||= false)
+        return super if options[:fallback_in_progress]
         default = extract_non_symbol_default!(options) if options[:default]
 
         begin
-          @fallback_locked = true
+          options[:fallback_in_progress] = true
           I18n.fallbacks[locale].each do |fallback|
             begin
               catch(:exception) do
@@ -52,7 +52,7 @@ def translate(locale, key, options = {})
             end
           end
         ensure
-          @fallback_locked = false
+          options.delete(:fallback_in_progress)
         end
 
         return super(locale, nil, options.merge(:default => default)) if default

lib/i18n/tests/localization/procs.rb

@@ -72,7 +72,7 @@ def self.inspect_args(args)
               when ::Date
                 arg.strftime('%a, %d %b %Y')
               when Hash
-                arg.delete(:fallback)
+                arg.delete(:fallback_in_progress)
                 arg.inspect
               else
                 arg.inspect

lib/i18n/tests/procs.rb

@@ -48,7 +48,7 @@ module Procs
 
 
       def self.filter_args(*args)
-        args.map {|arg| arg.delete(:fallback) if arg.is_a?(Hash) ; arg }.inspect
+        args.map {|arg| arg.delete(:fallback_in_progress) if arg.is_a?(Hash) ; arg }.inspect
       end
     end
   end