Optimize and clean up how details key get expired.

2 files changed, 30 insertions, 1 deletions

diff --git a/actionpack/lib/abstract_controller/rendering.rb b/actionpack/lib/abstract_controller/rendering.rb
index 5c34b83563..42f4939108 100644
--- a/actionpack/lib/abstract_controller/rendering.rb
+++ b/actionpack/lib/abstract_controller/rendering.rb
@@ -9,10 +9,38 @@ module AbstractController
     end
   end
 
+  # This is a class to fix I18n global state. Whenever you provide I18n.locale during a request,
+  # it will trigger the lookup_context and consequently expire the cache.
+  # TODO Add some deprecation warnings to remove I18n.locale from controllers
+  class I18nProxy < ::I18n::Config #:nodoc:
+    attr_reader :i18n_config, :lookup_context
+
+    def initialize(i18n_config, lookup_context)
+      @i18n_config, @lookup_context = i18n_config, lookup_context
+    end
+
+    def locale
+      @i18n_config.locale
+    end
+
+    def locale=(value)
+      @i18n_config.locale = value
+      @lookup_context.update_details(:locale => @i18n_config.locale)
+    end
+  end
+
   module Rendering
     extend ActiveSupport::Concern
     include AbstractController::ViewPaths
 
+    # Overwrite process to setup I18n proxy.
+    def process(*) #:nodoc:
+      old_config, I18n.config = I18n.config, I18nProxy.new(I18n.config, lookup_context)
+      super
+    ensure
+      I18n.config = old_config
+    end
+
     # An instance of a view class. The default view class is ActionView::Base
     #
     # The view class must have the following methods:
diff --git a/actionpack/lib/abstract_controller/view_paths.rb b/actionpack/lib/abstract_controller/view_paths.rb
index 6513c0778e..c2a9f6336d 100644
--- a/actionpack/lib/abstract_controller/view_paths.rb
+++ b/actionpack/lib/abstract_controller/view_paths.rb
@@ -7,7 +7,8 @@ module AbstractController
       self._view_paths = ActionView::PathSet.new
     end
 
-    delegate :template_exists?, :view_paths, :formats, :formats=, :to => :lookup_context
+    delegate :template_exists?, :view_paths, :formats, :formats=,
+             :locale, :locale=, :to => :lookup_context
 
     # LookupContext is the object responsible to hold all information required to lookup
     # templates, i.e. view paths and details. Check ActionView::LookupContext for more