Allow f.submit to be localized per object.

actionpack/lib/action_view/helpers/form_helper.rb

@@ -1096,6 +1096,14 @@ def error_messages(options = {})
       #         create: "Create a {{model}}"
       #         update: "Confirm changes to {{model}}"
       #
+      # It also searches for a key specific for the given object:
+      #
+      #   en:
+      #     helpers:
+      #       submit:
+      #         post:
+      #           create: "Add {{model}}"
+      #
       def submit(value=nil, options={})
         value, options = nil, value if value.is_a?(Hash)
         value ||= submit_default_value
@@ -1121,8 +1129,12 @@ def submit_default_value
             @object_name.to_s.humanize
           end
 
-          I18n.t(:"helpers.submit.#{key}", :model => model,
-                 :default => "#{key.to_s.humanize} #{model}")
+          defaults = []
+          defaults << :"helpers.submit.#{object_name}.#{key}"
+          defaults << :"helpers.submit.#{key}"
+          defaults << "#{key.to_s.humanize} #{model}"
+
+          I18n.t(defaults.shift, :model => model, :default => defaults)
         end
 
         def nested_attributes_association?(association_name)

actionpack/test/template/form_helper_test.rb

@@ -31,7 +31,10 @@ def setup
         :submit => {
           :create => 'Create {{model}}',
           :update => 'Confirm {{model}} changes',
-          :submit => 'Save changes'
+          :submit => 'Save changes',
+          :another_post => {
+            :update => 'Update your {{model}}'
+          }
         }
       }
     }
@@ -550,6 +553,21 @@ def test_submit_without_object_and_locale_strings
     I18n.locale = old_locale
   end
 
+  def test_submit_with_object_and_nested_lookup
+    old_locale, I18n.locale = I18n.locale, :submit
+
+    form_for(:another_post, @post) do |f|
+      concat f.submit
+    end
+
+    expected = "<form action='http://www.example.com' method='post'>" +
+               "<input name='commit' id='another_post_submit' type='submit' value='Update your Post' />" +
+               "</form>"
+    assert_dom_equal expected, output_buffer
+  ensure
+    I18n.locale = old_locale
+  end
+
   def test_nested_fields_for
     form_for(:post, @post) do |f|
       f.fields_for(:comment, @post) do |c|