Hobo Hobo → Hobo 1.3 (Rails 3)

Comments and changes to this ticket

• 

  Matt Jones October 9th, 2011 @ 09:01 PM

  (from [2498d176614a6ec016db6efe0f29ca9f83c9b243]) [#970] fix handling of before/after/prepend/append params with new ERB parser https://github.com/tablatom/hobo/commit/2498d176614a6ec016db6efe0f2...

• 

  Matt Jones October 9th, 2011 @ 09:12 PM

  • State changed from “new” to “resolved”
  • Milestone set to “Hobo 1.3 (Rails 3)”
  • Milestone order changed from “197985” to “0”

  Alright, finally ran this down. The core difficulty was an obscure case in Ruby syntax, where a setter (method ending in =) always returns its argument. This caused the problem since ActionView::OutputBuffer aliases << to append=, which we use to get block-helper compatibility working. In short, code like this:

  <extend tag="form" for="Task">
    <old-form merge>
      <after-field-list:><%= 'FOO' %></after-field-list:>
    </old-form>
  </extend>
  

  winds up with this compiled ERB at its heart:
  

              :field_list_replacement => proc { |_field_list_restore|
                new_context { ; 
                  concat(_field_list_restore.call({}, {})) ;
                  self.output_buffer.append= ( 'FOO' ); 
                } 
              },
  

  which gets the WRONG return value. Even something as simple as adding blank lines can change this:
  

  <extend tag="form" for="Task">
    <old-form merge>
      <after-field-list:>
        <%= 'FOO' %>
      </after-field-list:>
    </old-form>
  </extend>
  

  yields:
  

              :field_list_replacement => proc { |_field_list_restore|
                new_context { ;
                  concat(_field_list_restore.call({}, {})) ;
                  self.output_buffer.safe_concat("\n");
                  self.output_buffer.safe_concat('      ');
                  self.output_buffer.append= ( 'FOO' );
                  self.output_buffer.safe_concat("\n");
                }
              },
  

  which returns the correct value, since safe_concat returns the whole buffer.

  The fix included in the patch above should cover ANY possible case, since it ensures that each set of ERB <%= %> tags always returns the output buffer.