Fix human attribute_name to handle deeply nested attributes

This is a back-port of b0e2fc84 to Rails 3.2.
See #5843 and #3859 also.

2 files changed, 7 insertions, 2 deletions

diff --git a/activemodel/lib/active_model/translation.rb b/activemodel/lib/active_model/translation.rb
index 02b7c54d61..e560d9e2cf 100644
--- a/activemodel/lib/active_model/translation.rb
+++ b/activemodel/lib/active_model/translation.rb
@@ -44,9 +44,9 @@ module ActiveModel
     # Specify +options+ with additional translating options.
     def human_attribute_name(attribute, options = {})
       defaults  = []
-      parts     = attribute.to_s.split(".", 2)
+      parts     = attribute.to_s.split(".")
       attribute = parts.pop
-      namespace = parts.pop
+      namespace = parts.join("/") unless parts.empty?
 
       if namespace
         lookup_ancestors.each do |klass|
diff --git a/activemodel/test/cases/translation_test.rb b/activemodel/test/cases/translation_test.rb
index 54e86d48db..6bf92359c5 100644
--- a/activemodel/test/cases/translation_test.rb
+++ b/activemodel/test/cases/translation_test.rb
@@ -56,6 +56,11 @@ class ActiveModelI18nTests < ActiveModel::TestCase
     assert_equal 'person gender attribute', Person::Gender.human_attribute_name('attribute')
   end
 
+  def test_translated_deeply_nested_model_attributes
+    I18n.backend.store_translations 'en', :activemodel => {:attributes => {:"person/contacts/addresses" => {:street => 'Deeply Nested Address Street'}}}
+    assert_equal 'Deeply Nested Address Street', Person.human_attribute_name('contacts.addresses.street')
+  end
+
   def test_translated_nested_model_attributes
     I18n.backend.store_translations 'en', :activemodel => {:attributes => {:"person/addresses" => {:street => 'Person Address Street'}}}
     assert_equal 'Person Address Street', Person.human_attribute_name('addresses.street')