Ensure that prefixed attributes are properly namespaced when reparented

ext/java/nokogiri/XmlNode.java

@@ -1199,17 +1199,20 @@ public IRubyObject set(ThreadContext context, IRubyObject rbkey, IRubyObject rbv
             String val = rubyStringToString(rbval);
             Element element = (Element) node;
 
+            String uri = null;
             int colonIndex = key.indexOf(":");
             if (colonIndex > 0) {
               String prefix = key.substring(0, colonIndex);
-              String uri = null;
               if (prefix.equals("xml")) {
                 uri = "http://www.w3.org/XML/1998/namespace";
               } else if (prefix.equals("xmlns")) {
                 uri = "http://www.w3.org/2000/xmlns/";
               } else {
                 uri = findNamespaceHref(context, prefix);
               }
+            }
+
+            if (uri != null) {
               element.setAttributeNS(uri, key, val);
             } else {
               element.setAttribute(key, val);

lib/nokogiri/xml/node.rb

@@ -270,9 +270,9 @@ def []= name, value
       def add_child node_or_tags
         node_or_tags = coerce(node_or_tags)
         if node_or_tags.is_a?(XML::NodeSet)
-          node_or_tags.each { |n| add_child_node n }
+          node_or_tags.each { |n| add_child_node_and_reparent_attrs n }
         else
-          add_child_node node_or_tags
+          add_child_node_and_reparent_attrs node_or_tags
         end
         node_or_tags
       end
@@ -361,9 +361,9 @@ def children= node_or_tags
         node_or_tags = coerce(node_or_tags)
         children.unlink
         if node_or_tags.is_a?(XML::NodeSet)
-          node_or_tags.each { |n| add_child_node n }
+          node_or_tags.each { |n| add_child_node_and_reparent_attrs n }
         else
-          add_child_node node_or_tags
+          add_child_node_and_reparent_attrs node_or_tags
         end
         node_or_tags
       end
@@ -938,6 +938,15 @@ def implied_xpath_context
       def inspect_attributes
         [:name, :namespace, :attribute_nodes, :children]
       end
+
+      def add_child_node_and_reparent_attrs node
+        add_child_node node
+        node.attribute_nodes.find_all { |a| a.name =~ /:/ }.each do |attr_node|
+          attr_node.remove
+          node[attr_node.name] = attr_node.value
+        end
+      end
+
     end
   end
 end

test/namespaces/test_namespaces_in_builder_doc.rb

@@ -61,6 +61,15 @@ def test_builder_namespace_count
         ns_attrs = n.to_xml.scan(/\bxmlns(?::.+?)?=/)
         assert_equal 3, ns_attrs.length
       end
+
+      def test_builder_namespaced_attribute_on_unparented_node
+        doc = Nokogiri::XML::Builder.new do |x|
+          x.root('xmlns:foo' => 'http://foo.io') {
+            x.obj('foo:attr' => 'baz')
+          }
+        end.doc
+        assert_equal 'http://foo.io', doc.root.children.first.attribute_nodes.first.namespace.href
+      end
     end
   end
 end

test/namespaces/test_namespaces_in_created_doc.rb

@@ -63,6 +63,13 @@ def test_created_namespace_count
         ns_attrs = n.to_xml.scan(/\bxmlns(?::.+?)?=/)
         assert_equal 3, ns_attrs.length
       end
+
+      def test_created_namespaced_attribute_on_unparented_node
+        doc = Nokogiri::XML('<root xmlns:foo="http://foo.io"/>')
+        node = @doc.create_element('obj', 'foo:attr' => 'baz')
+        doc.root.add_child(node)
+        assert_equal 'http://foo.io', doc.root.children.first.attribute_nodes.first.namespace.href
+      end
     end
   end
 end