%= works for content_tag and does not require parenthesis on method call

actionpack/lib/action_view/template/handlers/erb.rb

@@ -3,52 +3,11 @@
 require 'erubis'
 
 module ActionView
-  class OutputBuffer
-    def initialize
-      @buffer = ActiveSupport::SafeBuffer.new
-    end
-
-    def safe_concat(value)
-      @buffer.safe_concat(value)
-    end
-
+  class OutputBuffer < ActiveSupport::SafeBuffer
     def <<(value)
-      @buffer << value.to_s
-    end
-
-    def length
-      @buffer.length
-    end
-
-    def [](*args)
-      @buffer[*args]
-    end
-
-    def to_s
-      @buffer.to_s
-    end
-
-    def to_str
-      @buffer.to_str
-    end
-
-    def empty?
-      @buffer.empty?
-    end
-
-    def html_safe?
-      @buffer.html_safe?
-    end
-
-    if "".respond_to?(:force_encoding)
-      def encoding
-        @buffer.encoding
-      end
-
-      def force_encoding(encoding)
-        @buffer.force_encoding(encoding)
-      end
+      super(value.to_s)
     end
+    alias :append= :<<
   end
 
   module Template::Handlers
@@ -64,14 +23,14 @@ def add_text(src, text)
 
       def add_expr_literal(src, code)
         if code =~ /(do|\{)(\s*\|[^|]*\|)?\s*\Z/
-          src << '@output_buffer << ' << code
+          src << '@output_buffer.append= ' << code
         else
-          src << '@output_buffer << (' << code << ');'
+          src << '@output_buffer.append= (' << code << ');'
         end
       end
 
       def add_expr_escaped(src, code)
-        src << '@output_buffer << ' << escaped_expr(code) << ';'
+        src << '@output_buffer.append= ' << escaped_expr(code) << ';'
       end
 
       def add_postamble(src)

actionpack/test/template/erb/tag_helper_test.rb

@@ -31,8 +31,8 @@ def render_content(start, inside)
       ActionView::Template::Handlers::Erubis.new(template).evaluate(context.new)
     end
 
-    test "percent equals works for content_tag" do
-      assert_equal "<div>Hello world</div>", render_content("content_tag(:div)", "Hello world")
+    test "percent equals works for content_tag and does not require parenthesis on method call" do
+      assert_equal "<div>Hello world</div>", render_content("content_tag :div", "Hello world")
     end
 
     test "percent equals works for javascript_tag" do