class-attribute is reordered when using .foo and (class="foo")

[mrcljx]

I was confused by this output when I tried to use jquery-tmpl conditions in the class:

# .a(class="{{if x}}{{/if}}")
Haml::Engine.new('.a(class="{{if x}}{{/if}}")').to_html
#=> "<div class='a x}}{{/if}} {{if'></div>\n"

# %div(class="a {{if x}}{{/if}}")
Haml::Engine.new('%div(class="a {{if x}}{{/if}}")').to_html
#=> "<div class='a {{if x}}{{/if}}'></div>\n"

The current behavior prevents duplicate classes (.foo(class="foo")) but it would be better just to leave the class-attribute order untouched.

[nex3]

I'm tentatively okay with this, but it's important that the classes are emitted in a deterministic order for testing purposes. Internally, Haml does array1 | array2 to ensure uniqueness of classes; if you can show that this maintains a deterministic order back through Ruby 1.8.6 I'll remove the sorting.

[k0kubun]

Closing because it passed 7 years without progress. Reopening because now we have progress.

[topherfangio]

For anyone else hitting this problem and needing a quick solution, I have hacked together some quick code (based on #882) that you can require to fix this.

# Override Haml to NOT sort class attributes.
#
# This is required because Semantic/Fomantic care about class ordering :facepalm:
#
# @see https://github.com/haml/haml/issues/306
module Haml
  module AttributeBuilder
    class << self
      alias_method :original_merge_value, :merge_value

      def merge_value(key, to, from)

        if key == 'class'
          merged_class = filter_and_join(from, ' ')
          if to && merged_class
            merged_class = (to.split(' ') | merged_class.split(' ')).join(' ')
          elsif to || merged_class
            merged_class ||= to
          end
          merged_class
        else
          original_merge_value(key, to, from)
        end

      end
    end
  end
end

I have not seen any problems yet, but please let me know if you find anything!

[HamptonMakes]

This has been implemented.