🐛 Handle nil when parsing fragment

lib/rexml/xpath_parser.rb

@@ -84,7 +84,12 @@ def parse path, node
         node = node.first
       end
 
-      node.document.__send__(:enable_cache) do
+      document = node.document
+      if document
+        document.__send__(:enable_cache) do
+          match( path_stack, node )
+        end
+      else
         match( path_stack, node )
       end
     end

test/parser/test_xpath.rb

@@ -4,7 +4,7 @@
 require "rexml/parsers/xpathparser"
 
 module REXMLTests
-  class TestXPathParser < Test::Unit::TestCase
+  class TestParserXPathParser < Test::Unit::TestCase
     sub_test_case("#abbreviate") do
       def abbreviate(xpath)
         parser = REXML::Parsers::XPathParser.new

test/test_xpath_parser.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module REXMLTests
+  class TestXPathParser < Test::Unit::TestCase
+    def setup
+      @root_element = make_service_element(["urn:type1", "urn:type2"], ["http://uri"])
+      @element = @root_element.children[0]
+      @parser = REXML::XPathParser.new
+    end
+
+    def make_service_element(types, uris)
+      root_element = REXML::Element.new
+      element = root_element.add_element("Service")
+      types.each do |type_text|
+        element.add_element("Type").text = type_text
+      end
+      uris.each do |uri_text|
+        element.add_element("URI").text = uri_text
+      end
+      root_element
+    end
+
+    def test_found
+      res = @parser.parse("/Service", @root_element)
+      assert_equal([@element],
+                   res)
+    end
+
+    def test_not_found
+      res = @parser.parse("/nonexistent", @root_element)
+      assert_equal([],
+                   res)
+    end
+  end
+end