Serializing unparented HTML node on JRuby

CHANGELOG.md

@@ -4,6 +4,13 @@ Nokogiri follows [Semantic Versioning](https://semver.org/), please see the [REA
 
 ---
 
+## next / unreleased
+
+### Fixed
+
+* [JRuby] Fixed NPE when serializing an unparented HTML node. [[#2559](https://github.com/sparklemotion/nokogiri/issues/2559), [#2895](https://github.com/sparklemotion/nokogiri/issues/2895)] (Thanks, [@cbasguti](https://github.com/cbasguti)!)
+
+
 ## 1.15.2 / 2023-05-24
 
 ### Dependencies

ext/java/nokogiri/internals/SaveContextVisitor.java

@@ -808,16 +808,13 @@ public int compare(Attr attr0, Attr attr1) {
   }
 
   private boolean
-  isHtmlScript(Text text)
+  isCDATA(Text text)
   {
-    return htmlDoc && text.getParentNode().getNodeName().equals("script");
+    Node parentNode = text.getParentNode();
+    return htmlDoc && parentNode != null && (parentNode.getNodeName().equals("style")
+           || parentNode.getNodeName().equals("script"));
   }
 
-  private boolean
-  isHtmlStyle(Text text)
-  {
-    return htmlDoc && text.getParentNode().getNodeName().equals("style");
-  }
 
   public boolean
   enter(Text text)
@@ -831,7 +828,7 @@ public int compare(Attr attr0, Attr attr1) {
       }
     }
 
-    if (shouldEncode(text) && !isHtmlScript(text) && !isHtmlStyle(text)) {
+    if (shouldEncode(text) && !isCDATA(text)) {
       textContent = encodeJavaString(textContent);
     }
 

test/xml/test_node.rb

@@ -1342,6 +1342,11 @@ def test_text_node_robustness_gh1426
           end
         end
 
+        # issue 2559
+        def test_serialize_unparented_node
+          assert_equal("asdf", Nokogiri::HTML4::Document.parse("<div></div>").create_text_node("asdf").to_s)
+        end
+
         describe "#wrap" do
           let(:xml) { "<root><thing><div>important thing</div></thing></root>" }
           let(:doc) { Nokogiri::XML(xml) }