From 8086d1f3fb9bc6cdcee3c4810bd4b876d930dc3a Mon Sep 17 00:00:00 2001
From: Mike Dalessio <mike@csa.net>
Date: Wed, 4 Nov 2009 18:49:48 -0500
Subject: [PATCH 1/3] cleaning up previous fix, because aaron has high
 standards. (higher than mine, anyway.)

---
 lib/nokogiri/xml/fragment_handler.rb | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/lib/nokogiri/xml/fragment_handler.rb b/lib/nokogiri/xml/fragment_handler.rb
index 68e046c14d..06f63e645b 100644
--- a/lib/nokogiri/xml/fragment_handler.rb
+++ b/lib/nokogiri/xml/fragment_handler.rb
@@ -28,13 +28,15 @@ def start_element name, attrs = []
         @doc_started = true if @original_html =~ regex
         return unless @doc_started
 
-        if @document.root and match = name.match(QNAME_REGEX)
-          prefix, name = match[1], match[2]
-          ns = @document.root.namespace_definitions.detect { |x|
-            x.prefix == prefix
-          }
-        else
-          ns = nil
+        ns = nil
+        if @document.root
+          match = name.match(QNAME_REGEX)
+          if match
+            prefix, name = match[1], match[2]
+            ns = @document.root.namespace_definitions.detect { |x|
+              x.prefix == prefix
+            }
+          end
         end
 
         node = Element.new(name, @document)

From 2ffddfce0dc2e5ac41fb75299922422c603b48b2 Mon Sep 17 00:00:00 2001
From: Chris Eppstein <chris@eppsteins.net>
Date: Fri, 6 Nov 2009 05:03:06 +0800
Subject: [PATCH 2/3] Test case for searching empty fragments.

---
 test/html/test_document_fragment.rb | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/test/html/test_document_fragment.rb b/test/html/test_document_fragment.rb
index abcf5a36b1..26e3aaa4ce 100644
--- a/test/html/test_document_fragment.rb
+++ b/test/html/test_document_fragment.rb
@@ -26,6 +26,16 @@ def test_fragment_should_have_document
         assert_equal @html, fragment.document
       end
 
+      def test_empty_fragment_should_be_searchable_by_css
+        fragment = Nokogiri::HTML.fragment("")
+        assert_equal 0, fragment.css("a").size
+      end
+
+      def test_empty_fragment_should_be_searchable
+        fragment = Nokogiri::HTML.fragment("")
+        assert_equal 0, fragment.search("//a").size
+      end
+
       def test_name
         fragment = Nokogiri::HTML::DocumentFragment.new(@html)
         assert_equal '#document-fragment', fragment.name

From 84aa2ea3a75108f8bc1351953fcec7324ba5ac8b Mon Sep 17 00:00:00 2001
From: Chris Eppstein <chris@eppsteins.net>
Date: Fri, 6 Nov 2009 05:29:44 +0800
Subject: [PATCH 3/3] Fix searching css on empty fragments.

---
 lib/nokogiri/xml/document_fragment.rb | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/nokogiri/xml/document_fragment.rb b/lib/nokogiri/xml/document_fragment.rb
index 7cf03773c9..af4450c082 100644
--- a/lib/nokogiri/xml/document_fragment.rb
+++ b/lib/nokogiri/xml/document_fragment.rb
@@ -51,7 +51,11 @@ def to_xml *args
       ###
       # Search this fragment.  See Nokogiri::XML::Node#css
       def css *args
-        children.css(*args)
+        if children.any?
+          children.css(*args)
+        else
+          NodeSet.new(document)
+        end
       end
 
       alias :serialize :to_s