From fce241b57f1e0292b143a11d31b8abf9ad949398 Mon Sep 17 00:00:00 2001
From: Jonathan Hedley <jonathan@hedley.net>
Date: Wed, 14 Jul 2021 11:35:39 +1000
Subject: [PATCH] Skip empty attribute values when serializing XML processing
 instructions

Fixes #770
---
 CHANGES                                              |  3 +++
 src/main/java/org/jsoup/nodes/XmlDeclaration.java    | 12 ++++++++++--
 .../java/org/jsoup/parser/XmlTreeBuilderTest.java    | 10 ++++++++++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index d60b728bb6..c07a143b4e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -8,6 +8,9 @@ jsoup changelog
 
   * Bugfix: when making a HTTP POST, if the request write fails, make sure the connection is immediately cleaned up.
 
+  * Bugfix: in the XML parser, XML processing instructions without attributes would be serialized as if they did.
+    <https://github.com/jhy/jsoup/issues/770>
+
   * Bugfix: updated the HtmlTreeParser resetInsertionMode to the current spec for supported elements
     <https://github.com/jhy/jsoup/issues/1491>
 
diff --git a/src/main/java/org/jsoup/nodes/XmlDeclaration.java b/src/main/java/org/jsoup/nodes/XmlDeclaration.java
index d7906eb6a6..6ab9b16241 100644
--- a/src/main/java/org/jsoup/nodes/XmlDeclaration.java
+++ b/src/main/java/org/jsoup/nodes/XmlDeclaration.java
@@ -52,9 +52,17 @@ public String getWholeDeclaration() {
 
     private void getWholeDeclaration(Appendable accum, Document.OutputSettings out) throws IOException {
         for (Attribute attribute : attributes()) {
-            if (!attribute.getKey().equals(nodeName())) { // skips coreValue (name)
+            String key = attribute.getKey();
+            String val = attribute.getValue();
+            if (!key.equals(nodeName())) { // skips coreValue (name)
                 accum.append(' ');
-                attribute.html(accum, out);
+                // basically like Attribute, but skip empty vals in XML
+                accum.append(key);
+                if (!val.isEmpty()) {
+                    accum.append("=\"");
+                    Entities.escape(accum, val, out, true, false, false);
+                    accum.append('"');
+                }
             }
         }
     }
diff --git a/src/test/java/org/jsoup/parser/XmlTreeBuilderTest.java b/src/test/java/org/jsoup/parser/XmlTreeBuilderTest.java
index d2527a9083..8fb0fbd8a8 100644
--- a/src/test/java/org/jsoup/parser/XmlTreeBuilderTest.java
+++ b/src/test/java/org/jsoup/parser/XmlTreeBuilderTest.java
@@ -152,6 +152,16 @@ public void testParseDeclarationAttributes() {
         assertEquals("<?xml version=\"1\" encoding=\"UTF-8\" something=\"else\"?>", decl.outerHtml());
     }
 
+    @Test
+    public void testParseDeclarationWithoutAttributes() {
+        String xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<?myProcessingInstruction My Processing instruction.?>";
+        Document doc = Jsoup.parse(xml, "", Parser.xmlParser());
+        XmlDeclaration decl = (XmlDeclaration) doc.childNode(2);
+        assertEquals("myProcessingInstruction", decl.name());
+        assertTrue(decl.hasAttr("My"));
+        assertEquals("<?myProcessingInstruction My Processing instruction.?>", decl.outerHtml());
+    }
+
     @Test
     public void caseSensitiveDeclaration() {
         String xml = "<?XML version='1' encoding='UTF-8' something='else'?>";