Fix inconsistencies in path with missing helpers

Ruby 2.0 and later demonstrate some inconsistencies when a helper file
is not found with the path method on LoadError. By creating a subclass
of LoadError we can cater for the inconsistencies.

2 files changed, 18 insertions, 2 deletions

diff --git a/actionpack/lib/abstract_controller/helpers.rb b/actionpack/lib/abstract_controller/helpers.rb
index 77cc4c07d9..7a9055a679 100644
--- a/actionpack/lib/abstract_controller/helpers.rb
+++ b/actionpack/lib/abstract_controller/helpers.rb
@@ -12,6 +12,15 @@ module AbstractController
       self._helper_methods = Array.new
     end
 
+    class MissingHelperError < LoadError
+      def initialize(error, path)
+        @error = error
+        @path  = "helpers/#{path}.rb"
+        set_backtrace error.backtrace
+        super("Missing helper file helpers/%s.rb" % path)
+      end
+    end
+
     module ClassMethods
       # When a class is inherited, wrap its helper module in a new module.
       # This ensures that the parent class's module can be changed
@@ -132,7 +141,11 @@ module AbstractController
           case arg
           when String, Symbol
             file_name = "#{arg.to_s.underscore}_helper"
-            require_dependency(file_name, "Missing helper file helpers/%s.rb")
+            begin
+              require_dependency(file_name)
+            rescue LoadError => e
+              raise MissingHelperError.new(e, file_name)
+            end
             file_name.camelize.constantize
           when Module
             arg
diff --git a/actionpack/test/abstract/helper_test.rb b/actionpack/test/abstract/helper_test.rb
index b28a5b5afb..2e86e7e859 100644
--- a/actionpack/test/abstract/helper_test.rb
+++ b/actionpack/test/abstract/helper_test.rb
@@ -69,7 +69,10 @@ module AbstractController
       end
 
       def test_declare_missing_helper
-        assert_raise(MissingSourceFile) { AbstractHelpers.helper :missing }
+        e = assert_raise AbstractController::Helpers::MissingHelperError do
+          AbstractHelpers.helper :missing
+        end
+        assert_equal "helpers/missing_helper.rb", e.path
       end
 
       def test_helpers_with_module_through_block