Don't treat the 'data' attribute specially.

Fixes #678

CHANGELOG.md

@@ -9,6 +9,7 @@
   for detailed info. (Matt Wildig)
 * Make escape_once respect hexadecimal references. (Matt Wildig)
 * General performance and memory usage improvements. (Akira Matsuda)
+* Don't treat the 'data' attribute specially when merging attribute hashes. (Matt Wildig and Norman Clarke)
 
 ## 4.0.2
 

lib/haml/buffer.rb

@@ -246,16 +246,21 @@ RUBY
         from['class'] ||= to['class']
       end
 
-      from_data = from.delete('data')
-      # forces to_data & from_data into a hash
-      from_data = { nil => from_data } if from_data && !from_data.is_a?(Hash)
-      to['data'] = { nil => to['data'] } if to['data'] && !to['data'].is_a?(Hash)
+      from.keys.each do |key|
+        next unless from[key].kind_of?(Hash) || to[key].kind_of?(Hash)
 
-      if from_data && !to['data']
-        to['data'] = from_data
-      elsif from_data && to['data']
-        to['data'].merge! from_data
+        from_data = from.delete(key)
+        # forces to_data & from_data into a hash
+        from_data = { nil => from_data } if from_data && !from_data.is_a?(Hash)
+        to[key] = { nil => to[key] } if to[key] && !to[key].is_a?(Hash)
+
+        if from_data && !to[key]
+          to[key] = from_data
+        elsif from_data && to[key]
+          to[key].merge! from_data
+        end
       end
+
       to.merge!(from)
     end
 

test/engine_test.rb

@@ -214,11 +214,6 @@ HAML
                  render(".no_attributes{:nil => nil}").chomp)
   end
 
-  def test_attribute_method_with_both_attrib_styles_and_non_static_hashes
-    assert_equal("<div baz='qux' foo='bar' zig='zag'></div>",
-                render("%div{{:foo => 'bar'}, :baz => 'qux'}(zig = val)", :locals => {:val => 'zag'}).chomp)
-  end
-
   def test_strings_should_get_stripped_inside_tags
     assert_equal("<div class='stripped'>This should have no spaces in front of it</div>",
                  render(".stripped    This should have no spaces in front of it").chomp)
@@ -1458,6 +1453,15 @@ HAML
       render("%div{:foo => {:baz => 'bang'}}"))
 	end
 
+  def test_arbitrary_attribute_hash_merging
+    assert_equal(%Q{<a aria-baz='qux' aria-foo='bar'></a>\n}, render(<<-HAML))
+- h1 = {:aria => {:foo => :bar}}
+- h2 = {:baz => :qux}
+%a{h1, :aria => h2}
+HAML
+  end
+
+
   def test_html5_data_attributes_with_nested_hash
     assert_equal("<div data-a-b='c'></div>\n", render(<<-HAML))
 - hash = {:a => {:b => 'c'}}