I18n.reload! is only called if any of the locale files actually changed.

3 files changed, 82 insertions, 71 deletions

diff --git a/activesupport/lib/active_support/i18n.rb b/activesupport/lib/active_support/i18n.rb
index 0ffdd904fd..45b9d20c01 100644
--- a/activesupport/lib/active_support/i18n.rb
+++ b/activesupport/lib/active_support/i18n.rb
@@ -4,5 +4,6 @@ rescue LoadError => e
   $stderr.puts "You don't have i18n installed in your application. Please add it to your Gemfile and run bundle install"
   raise e
 end
+
 I18n.load_path << "#{File.dirname(__FILE__)}/locale/en.yml"
 ActiveSupport.run_load_hooks(:i18n)
diff --git a/activesupport/lib/active_support/i18n_railtie.rb b/activesupport/lib/active_support/i18n_railtie.rb
new file mode 100644
index 0000000000..d82e54f1d4
--- /dev/null
+++ b/activesupport/lib/active_support/i18n_railtie.rb
@@ -0,0 +1,80 @@
+require "active_support"
+require "rails"
+require "active_support/file_update_checker"
+
+module I18n
+  class Railtie < Rails::Railtie
+    config.i18n = ActiveSupport::OrderedOptions.new
+    config.i18n.railties_load_path = []
+    config.i18n.load_path = []
+    config.i18n.fallbacks = ActiveSupport::OrderedOptions.new
+
+    def self.reloader
+      @reloader ||= ActiveSupport::FileUpdateChecker.new([]){ I18n.reload! }
+    end
+
+    # Add I18n::Railtie.reloader to ActionDispatch callbacks. Since, at this
+    # point, no path was added to the reloader, I18n.reload! is not triggered
+    # on to_prepare callbacks. This will only happen on the config.after_initialize
+    # callback below.
+    initializer "i18n.callbacks" do
+      ActionDispatch::Callbacks.to_prepare do
+        I18n::Railtie.reloader.execute_if_updated
+      end
+    end
+
+    # Set the i18n configuration only after initialization since a lot of
+    # configuration is still usually done in application initializers.
+    config.after_initialize do |app|
+      fallbacks = app.config.i18n.delete(:fallbacks)
+
+      app.config.i18n.each do |setting, value|
+        case setting
+        when :railties_load_path
+          app.config.i18n.load_path.unshift(*value)
+        when :load_path
+          I18n.load_path += value
+        else
+          I18n.send("#{setting}=", value)
+        end
+      end
+
+      init_fallbacks(fallbacks) if fallbacks && validate_fallbacks(fallbacks)
+
+      reloader.paths.concat I18n.load_path
+      reloader.execute_if_updated
+    end
+
+  protected
+
+    def self.include_fallbacks_module
+      I18n.backend.class.send(:include, I18n::Backend::Fallbacks)
+    end
+
+    def self.init_fallbacks(fallbacks)
+      include_fallbacks_module
+
+      args = case fallbacks
+      when ActiveSupport::OrderedOptions
+        [*(fallbacks[:defaults] || []) << fallbacks[:map]].compact
+      when Hash, Array
+        Array.wrap(fallbacks)
+      else # TrueClass
+        []
+      end
+
+      I18n.fallbacks = I18n::Locale::Fallbacks.new(*args)
+    end
+  
+    def self.validate_fallbacks(fallbacks)
+      case fallbacks
+      when ActiveSupport::OrderedOptions
+        !fallbacks.empty?
+      when TrueClass, Array, Hash
+        true
+      else
+        raise "Unexpected fallback type #{fallbacks.inspect}"
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/activesupport/lib/active_support/railtie.rb b/activesupport/lib/active_support/railtie.rb
index 59f9ab18b1..1f32f8718f 100644
--- a/activesupport/lib/active_support/railtie.rb
+++ b/activesupport/lib/active_support/railtie.rb
@@ -1,5 +1,6 @@
 require "active_support"
 require "rails"
+require "active_support/i18n_railtie"
 
 module ActiveSupport
   class Railtie < Rails::Railtie
@@ -26,75 +27,4 @@ module ActiveSupport
       Time.zone_default = zone_default
     end
   end
-end
-
-module I18n
-  class Railtie < Rails::Railtie
-    config.i18n = ActiveSupport::OrderedOptions.new
-    config.i18n.railties_load_path = []
-    config.i18n.load_path = []
-    config.i18n.fallbacks = ActiveSupport::OrderedOptions.new
-
-    initializer "i18n.initialize" do
-      ActiveSupport.on_load(:i18n) do
-        I18n.reload!
-
-        ActionDispatch::Callbacks.to_prepare do
-          I18n.reload!
-        end
-      end
-    end
-
-    # Set the i18n configuration from config.i18n but special-case for
-    # the load_path which should be appended to what's already set instead of overwritten.
-    config.after_initialize do |app|
-      fallbacks = app.config.i18n.delete(:fallbacks)
-
-      app.config.i18n.each do |setting, value|
-        case setting
-        when :railties_load_path
-          app.config.i18n.load_path.unshift(*value)
-        when :load_path
-          I18n.load_path += value
-        else
-          I18n.send("#{setting}=", value)
-        end
-      end
-
-      init_fallbacks(fallbacks) if fallbacks && validate_fallbacks(fallbacks)
-      I18n.reload!
-    end
-
-    class << self
-      protected
-
-        def init_fallbacks(fallbacks)
-          include_fallbacks_module
-          args = case fallbacks
-          when ActiveSupport::OrderedOptions
-            [*(fallbacks[:defaults] || []) << fallbacks[:map]].compact
-          when Hash, Array
-            Array.wrap(fallbacks)
-          else # TrueClass
-            []
-          end
-          I18n.fallbacks = I18n::Locale::Fallbacks.new(*args)
-        end
-
-        def include_fallbacks_module
-          I18n.backend.class.send(:include, I18n::Backend::Fallbacks)
-        end
-      
-        def validate_fallbacks(fallbacks)
-          case fallbacks
-          when ActiveSupport::OrderedOptions
-            !fallbacks.empty?
-          when TrueClass, Array, Hash
-            true
-          else
-            raise "Unexpected fallback type #{fallbacks.inspect}"
-          end
-        end
-    end
-  end
 end
\ No newline at end of file