From 8a4bdaef7aeaaa62d4016b890cdca87b1a701b7f Mon Sep 17 00:00:00 2001
From: Jonathan Hedley <jonathan@hedley.net>
Date: Sun, 17 Dec 2023 12:06:44 +1100
Subject: [PATCH] Output polyglot commented CData sections in XML mode

And only if the data does not already contain a (pseudo) CData section.

Fixes #2078
---
 CHANGES.md                                    |  3 +
 src/main/java/org/jsoup/nodes/DataNode.java   | 20 +++--
 .../java/org/jsoup/helper/W3CDomTest.java     | 13 +++-
 .../java/org/jsoup/nodes/DataNodeTest.java    | 73 +++++++++++++++++++
 .../java/org/jsoup/nodes/ElementTest.java     | 50 +++++++++++--
 5 files changed, 143 insertions(+), 16 deletions(-)
 create mode 100644 src/test/java/org/jsoup/nodes/DataNodeTest.java

diff --git a/CHANGES.md b/CHANGES.md
index 3c1b3f1850..dca3f9b23c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -21,6 +21,9 @@
   `parent [attr=va]`, causing incorrect selections. The fix includes a EvaluatorDebug class that generates a sexpr
   to represent the query, allowing simpler and more thorough query parse
   tests. [2073](https://github.com/jhy/jsoup/issues/2073)
+* When generating XML-syntax output from parsed HTML, script nodes containing (pseudo) CData sections would have an
+  extraneous CData section added, causing script execution errors. Now, the data content is emitted in a HTML/XML/XHTML
+  polyglot format, if the data is not already within a CData section. [2078](https://github.com/jhy/jsoup/issues/2078)
 
 ---
 Older changes for versions 0.1.1 (2010-Jan-31) through 1.17.1 (2023-Nov-27) may be found in
diff --git a/src/main/java/org/jsoup/nodes/DataNode.java b/src/main/java/org/jsoup/nodes/DataNode.java
index 4a0cf434f2..a357285528 100644
--- a/src/main/java/org/jsoup/nodes/DataNode.java
+++ b/src/main/java/org/jsoup/nodes/DataNode.java
@@ -1,6 +1,8 @@
 package org.jsoup.nodes;
 
 import java.io.IOException;
+import java.util.regex.Pattern;
+
 import org.jsoup.nodes.Entities.EscapeMode;
 
 /**
@@ -41,14 +43,18 @@ public DataNode setWholeData(String data) {
 
     @Override
     void outerHtmlHead(Appendable accum, int depth, Document.OutputSettings out) throws IOException {
-        if (out.syntax() == Document.OutputSettings.Syntax.xml) {
-            // In XML mode, output data nodes as CDATA, so can parse as XML
-            accum
-                .append("<![CDATA[")
-                .append(getWholeData())
-                .append("]]>");
+        /* For XML output, escape the DataNode in a CData section. The data may contain pseudo-CData content if it was
+        parsed as HTML, so don't double up Cdata. Output in polygot HTML / XHTML / XML format. */
+        final String data = getWholeData();
+        if (out.syntax() == Document.OutputSettings.Syntax.xml && !data.contains("<![CDATA[")) {
+            if (hasParent() && parentNode.normalName().equals("script"))
+                accum.append("//<![CDATA[\n").append(data).append("\n//]]>");
+            else if (hasParent() && parentNode.normalName().equals("style"))
+                accum.append("/*<![CDATA[*/\n").append(data).append("\n/*]]>*/");
+            else
+                accum.append("<![CDATA[").append(data).append("]]>");
         } else {
-            // In HTML, data is not escaped in return from data nodes, so " in script, style is plain
+            // In HTML, data is not escaped in the output of data nodes, so < and & in script, style is OK
             accum.append(getWholeData());
         }
     }
diff --git a/src/test/java/org/jsoup/helper/W3CDomTest.java b/src/test/java/org/jsoup/helper/W3CDomTest.java
index fe8379aea8..de0ce16694 100644
--- a/src/test/java/org/jsoup/helper/W3CDomTest.java
+++ b/src/test/java/org/jsoup/helper/W3CDomTest.java
@@ -351,12 +351,17 @@ public void canOutputHtmlWithoutNamespace() {
         org.jsoup.nodes.Document jdoc = Jsoup.parse(html);
         jdoc.outputSettings().syntax(org.jsoup.nodes.Document.OutputSettings.Syntax.xml);
         String xml = jdoc.body().html();
-        assertTrue(xml.contains("<script><![CDATA[")); // as asserted in ElementTest
+        assertTrue(xml.contains("<script>//<![CDATA[\n1 && 2\n//]]></script>")); // as asserted in ElementTest
         Document doc = parseXml(xml, false);
         NodeList list = xpath(doc, "//script");
-        assertEquals(1, list.getLength());
-        Node script = list.item(0); // will be the cdata node
-        assertEquals("1 && 2", script.getTextContent());
+        assertEquals(2, list.getLength());
+        Node scriptComment = list.item(0); // will be the cdata node
+        assertEquals("//", scriptComment.getTextContent());
+        Node script = list.item(1);
+        assertEquals("\n" +
+            "1 && 2\n" +
+            "//", script.getTextContent());
+
     }
 
     @Test public void handlesEmptyDoctype() {
diff --git a/src/test/java/org/jsoup/nodes/DataNodeTest.java b/src/test/java/org/jsoup/nodes/DataNodeTest.java
new file mode 100644
index 0000000000..a7b626dee2
--- /dev/null
+++ b/src/test/java/org/jsoup/nodes/DataNodeTest.java
@@ -0,0 +1,73 @@
+package org.jsoup.nodes;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class DataNodeTest {
+
+    @Test
+    public void xmlOutputScriptWithCData() throws IOException {
+        DataNode node = new DataNode("//<![CDATA[\nscript && <> data]]>");
+        node.parentNode = new Element("script");
+        StringBuilder accum = new StringBuilder();
+        node.outerHtmlHead(accum, 0, new Document.OutputSettings().syntax(Document.OutputSettings.Syntax.xml));
+        assertEquals("//<![CDATA[\nscript && <> data]]>", accum.toString());
+    }
+
+    @Test
+    public void xmlOutputScriptWithoutCData() throws IOException {
+        DataNode node = new DataNode("script && <> data");
+        node.parentNode = new Element("script");
+        StringBuilder accum = new StringBuilder();
+        node.outerHtmlHead(accum, 0, new Document.OutputSettings().syntax(Document.OutputSettings.Syntax.xml));
+        assertEquals("//<![CDATA[\nscript && <> data\n//]]>", accum.toString());
+    }
+
+    @Test
+    public void xmlOutputStyleWithCData() throws IOException {
+        DataNode node = new DataNode("/*<![CDATA[*/\nstyle && <> data]]>");
+        node.parentNode = new Element("style");
+        StringBuilder accum = new StringBuilder();
+        node.outerHtmlHead(accum, 0, new Document.OutputSettings().syntax(Document.OutputSettings.Syntax.xml));
+        assertEquals("/*<![CDATA[*/\nstyle && <> data]]>", accum.toString());
+    }
+
+    @Test
+    public void xmlOutputStyleWithoutCData() throws IOException {
+        DataNode node = new DataNode("style && <> data");
+        node.parentNode = new Element("style");
+        StringBuilder accum = new StringBuilder();
+        node.outerHtmlHead(accum, 0, new Document.OutputSettings().syntax(Document.OutputSettings.Syntax.xml));
+        assertEquals("/*<![CDATA[*/\nstyle && <> data\n/*]]>*/", accum.toString());
+    }
+
+    @Test
+    public void xmlOutputOtherWithCData() throws IOException {
+        DataNode node = new DataNode("<![CDATA[other && <> data]]>");
+        node.parentNode = new Element("other");
+        StringBuilder accum = new StringBuilder();
+        node.outerHtmlHead(accum, 0, new Document.OutputSettings().syntax(Document.OutputSettings.Syntax.xml));
+        assertEquals("<![CDATA[other && <> data]]>", accum.toString());
+    }
+
+    @Test
+    public void xmlOutputOtherWithoutCData() throws IOException {
+        DataNode node = new DataNode("other && <> data");
+        node.parentNode = new Element("other");
+        StringBuilder accum = new StringBuilder();
+        node.outerHtmlHead(accum, 0, new Document.OutputSettings().syntax(Document.OutputSettings.Syntax.xml));
+        assertEquals("<![CDATA[other && <> data]]>", accum.toString());
+    }
+
+    @Test
+    public void xmlOutputOrphanWithoutCData() throws IOException {
+        DataNode node = new DataNode("other && <> data");
+        StringBuilder accum = new StringBuilder();
+        node.outerHtmlHead(accum, 0, new Document.OutputSettings().syntax(Document.OutputSettings.Syntax.xml));
+        assertEquals("<![CDATA[other && <> data]]>", accum.toString());
+    }
+
+}
diff --git a/src/test/java/org/jsoup/nodes/ElementTest.java b/src/test/java/org/jsoup/nodes/ElementTest.java
index b4d3747754..71a43b7898 100644
--- a/src/test/java/org/jsoup/nodes/ElementTest.java
+++ b/src/test/java/org/jsoup/nodes/ElementTest.java
@@ -2755,16 +2755,56 @@ void prettySerializationRoundTrips(Document.OutputSettings settings) {
         assertEquals("1 && 2", scriptDataNode.getWholeData());
 
         doc.outputSettings().syntax(Document.OutputSettings.Syntax.xml);
-        String xml = doc.body().html();
+        Element p = doc.expectFirst("p");
+        String xml = p.html();
+        assertEquals(
+            "<script>//<![CDATA[\n" +
+                "1 && 2\n" +
+                "//]]></script>\n" +
+                "<style>/*<![CDATA[*/\n" +
+                "3 && 4\n" +
+                "/*]]>*/</style> 5 &amp;&amp; 6",
+            xml);
+
+        Document xmlDoc = Jsoup.parse(xml, Parser.xmlParser());
+        assertEquals(xml, xmlDoc.html());
+        Element scriptXmlEl = xmlDoc.expectFirst("script");
+        TextNode scriptText = (TextNode) scriptXmlEl.childNode(0);
+        assertEquals("//", scriptText.getWholeText());
+        CDataNode scriptCdata = (CDataNode) scriptXmlEl.childNode(1);
+        assertEquals("\n1 && 2\n//", scriptCdata.text());
+    }
+
+    @Test void datanodesOutputExistingCdataInXhtml() {
+        String html = "<p><script>//<![CDATA[\n1 && 2\n//]]></script><style>\n/*<![CDATA[*/3 && 4\n/*]]>*/</style> 5 &amp;&amp; 6</p>";;
+        Document doc = Jsoup.parse(html); // parsed as HTML
+        String out = TextUtil.normalizeSpaces(doc.body().html());
+        assertEquals("<p><script>//<![CDATA[1 && 2//]]></script><style>/*<![CDATA[*/3 && 4/*]]>*/</style> 5 &amp;&amp; 6</p>", out);
+        Element scriptEl = doc.expectFirst("script");
+        DataNode scriptDataNode = (DataNode) scriptEl.childNode(0);
+        assertEquals("//<![CDATA[\n" +
+            "1 && 2\n" +
+            "//]]>", scriptDataNode.getWholeData());
+
+        doc.outputSettings().syntax(Document.OutputSettings.Syntax.xml);
+        Element p = doc.expectFirst("p");
+        String xml = p.html();
         assertEquals(
-            "<p><script><![CDATA[1 && 2]]></script><style><![CDATA[3 && 4]]></style> 5 &amp;&amp; 6</p>",
-            TextUtil.normalizeSpaces(xml));
+            "<script>//<![CDATA[\n" +
+                "1 && 2\n" +
+                "//]]></script>\n" +
+                "<style>\n" +
+                "/*<![CDATA[*/3 && 4\n" +
+                "/*]]>*/</style> 5 &amp;&amp; 6",
+            xml);
 
         Document xmlDoc = Jsoup.parse(xml, Parser.xmlParser());
         assertEquals(xml, xmlDoc.html());
         Element scriptXmlEl = xmlDoc.expectFirst("script");
-        CDataNode scriptCdata = (CDataNode) scriptXmlEl.childNode(0);
-        assertEquals(scriptCdata.text(), scriptDataNode.getWholeData());
+        TextNode scriptText = (TextNode) scriptXmlEl.childNode(0);
+        assertEquals("//", scriptText.getWholeText());
+        CDataNode scriptCdata = (CDataNode) scriptXmlEl.childNode(1);
+        assertEquals("\n1 && 2\n//", scriptCdata.text());
     }
 
     @Test void outerHtmlAppendable() {