[Sass] Support long selectors extending.

lib/sass/selector.rb

@@ -187,7 +187,7 @@ module Sass
       # @todo Link this to the reference documentation on `@extend`
       #   when such a thing exists.
       #
-      # @param extends [{Selector::Node => Selector::Node}]
+      # @param extends [{Selector::Node => Selector::SimpleSequence}]
       #   The extensions to perform on this selector
       # @return [CommaSequence] A copy of this selector,
       #   with extensions made according to `extends`
@@ -288,7 +288,7 @@ module Sass
       # with the extensions specified in a hash
       # (which should be populated via {Sass::Tree::Node#cssize}).
       #
-      # @param extends [{Selector::Node => Selector::Node}]
+      # @param extends [{Selector::Node => Selector::SimpleSequence}]
       #   The extensions to perform on this selector
       # @return [Array<Sequence>] A list of selectors generated
       #   by extending this selector with `extends`.
@@ -390,7 +390,7 @@ module Sass
       # (which should be populated via {Sass::Tree::Node#cssize}).
       #
       # @overload def extend(extends)
-      # @param extends [{Selector::Node => Selector::Node}]
+      # @param extends [{Selector::Node => Selector::SimpleSequence}]
       #   The extensions to perform on this selector
       # @return [Array<SimpleSequence>] A list of selectors generated
       #   by extending this selector with `extends`.
@@ -403,7 +403,12 @@ module Sass
         seqs = Haml::Util.enum_with_index(members).map do |sel, i|
           next unless extenders = extends[sel]
           sseq_without_sel = members[0...i] + members[i+1..-1]
-          extenders.map {|sel2| sel2.unify(sseq_without_sel)}
+          extenders.map do |sseq|
+            sseq.members.inject(sseq_without_sel) do |sseq2, sel2|
+              next unless sseq2
+              sel2.unify(sseq2)
+            end
+          end
         end.flatten(1).compact.map {|seq| SimpleSequence.new(seq)}
         seqs.concat seqs.map {|seq| seq.extend(extends)}.flatten.uniq
       rescue SystemStackError

lib/sass/tree/extend_node.rb

@@ -34,11 +34,7 @@ module Sass::Tree
             raise Sass::SyntaxError.new("#{seq.to_a.join} can't extend: invalid selector")
           end
 
-          if sseq.members.size > 1
-            raise Sass::SyntaxError.new("#{seq.to_a.join} can't extend: long selectors can't extend ")
-          end
-
-          extends[sel] << sseq.members.first
+          extends[sel] << sseq
         end
       end
 

lib/sass/tree/node.rb

@@ -166,7 +166,7 @@ module Sass
       # @todo Link this to the reference documentation on `@extend`
       #   when such a thing exists.
       #
-      # @param extends [{Selector::Node => Selector::Node}]
+      # @param extends [{Selector::Node => Selector::SimpleSequence}]
       #   The extensions to perform on this tree
       # @return [Tree::Node] The resulting tree of static CSS nodes.
       # @raise [Sass::SyntaxError] Only if there's a programmer error

test/sass/extend_test.rb

@@ -838,6 +838,46 @@ a.baz {@extend .foo.bar}
 SCSS
   end
 
+  ## Long Extenders
+
+  def test_long_extender
+    assert_equal <<CSS, render(<<SCSS)
+.foo.bar, .bar.baz.bang {
+  a: b; }
+CSS
+.foo.bar {a: b}
+.baz.bang {@extend .foo}
+SCSS
+  end
+
+  def test_long_extender_runs_unification
+    assert_equal <<CSS, render(<<SCSS)
+ns|*.foo.bar, ns|a.bar.baz {
+  a: b; }
+CSS
+ns|*.foo.bar {a: b}
+a.baz {@extend .foo}
+SCSS
+  end
+
+  def test_long_extender_aborts_unification
+    assert_equal <<CSS, render(<<SCSS)
+a.foo#bar {
+  a: b; }
+CSS
+a.foo#bar {a: b}
+h1.baz {@extend .foo}
+SCSS
+
+    assert_equal <<CSS, render(<<SCSS)
+a.foo#bar {
+  a: b; }
+CSS
+a.foo#bar {a: b}
+.bang#baz {@extend .foo}
+SCSS
+  end
+
   private
 
   def render(sass, options = {})