Ruby 1.9: ERB template encoding using a magic comment at the top of t…

…he file

actionpack/CHANGELOG

@@ -1,4 +1,7 @@
-*Edge*
+*2.3.6 (unreleased)*
+
+* Ruby 1.9: ERB template encoding using a magic comment at the top of the file.  [Jeremy Kemper]
+    <%# encoding: utf-8 %>
 
 * Fixed that default locale templates should be used if the current locale template is missing [DHH]
 

actionpack/lib/action_view/renderable.rb

@@ -65,16 +65,26 @@ def compile(local_assigns)
       def compile!(render_symbol, local_assigns)
         locals_code = local_assigns.keys.map { |key| "#{key} = local_assigns[:#{key}];" }.join
 
+        code = compiled_source
+        encoding_comment = $1 if code.sub!(/\A(#.*coding.*)\n/, '')
+
         source = <<-end_src
           def #{render_symbol}(local_assigns)
-            old_output_buffer = output_buffer;#{locals_code};#{compiled_source}
+            old_output_buffer = output_buffer;#{locals_code};#{code}
           ensure
             self.output_buffer = old_output_buffer
           end
         end_src
 
+        if encoding_comment
+          source = "#{encoding_comment}\n#{source}"
+          line = -1
+        else
+          line = 0
+        end
+
         begin
-          ActionView::Base::CompiledTemplates.module_eval(source, filename, 0)
+          ActionView::Base::CompiledTemplates.module_eval(source, filename, line)
         rescue Errno::ENOENT => e
           raise e # Missing template file, re-raise for Base to rescue
         rescue Exception => e # errors from template code

actionpack/lib/action_view/template_handlers/erb.rb

@@ -11,11 +11,7 @@ class ERB < TemplateHandler
       self.erb_trim_mode = '-'
 
       def compile(template)
-        src = ::ERB.new("<% __in_erb_template=true %>#{template.source}", nil, erb_trim_mode, '@output_buffer').src
-
-        # Ruby 1.9 prepends an encoding to the source. However this is
-        # useless because you can only set an encoding on the first line
-        RUBY_VERSION >= '1.9' ? src.sub(/\A#coding:.*\n/, '') : src
+        ::ERB.new("<% __in_erb_template=true %>#{template.source}", nil, erb_trim_mode, '@output_buffer').src
       end
     end
   end

actionpack/test/fixtures/test/utf8.html.erb

@@ -1,2 +1,5 @@
+<%# encoding: utf-8 -%>
 Русский текст
-日本語のテキスト
+<%= "日".encoding %>
+<%= @output_buffer.encoding %>
+<%= __ENCODING__ %>

actionpack/test/template/render_test.rb

@@ -251,7 +251,7 @@ def test_render_with_nested_layout
   if '1.9'.respond_to?(:force_encoding)
     def test_render_utf8_template
       result = @view.render(:file => "test/utf8.html.erb", :layouts => "layouts/yield")
-      assert_equal "Русский текст\n日本語のテキスト", result
+      assert_equal "Русский текст\nUTF-8\nUTF-8\nUTF-8\n", result
       assert_equal Encoding::UTF_8, result.encoding
     end
   end