From fb3a71a14dcd5b43cbf2850ea678603f8b487bdd Mon Sep 17 00:00:00 2001
From: Florian Schmaus <flo@geekplace.eu>
Date: Wed, 18 Sep 2019 08:48:39 +0200
Subject: [PATCH] Fix ConcurrentModificationException in
 XmlStringBuilder.appendToXml()

We want to append to appendable, not sb, the LazyStringBuilder we are
currently iterating over,
---
 .../main/java/org/jivesoftware/smack/util/XmlStringBuilder.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/smack-core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java b/smack-core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java
index acf5ac1b4..ae8b2931b 100644
--- a/smack-core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java
+++ b/smack-core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java
@@ -646,7 +646,7 @@ public class XmlStringBuilder implements Appendable, CharSequence, Element {
             else if (csq instanceof XmlNsAttribute) {
                 XmlNsAttribute xmlNsAttribute = (XmlNsAttribute) csq;
                 if (!xmlNsAttribute.value.equals(enclosingXmlEnvironment.getEffectiveNamespace())) {
-                    sb.append(xmlNsAttribute);
+                    appendable.append(xmlNsAttribute);
                     enclosingXmlEnvironment = new XmlEnvironment(xmlNsAttribute.value);
                 }
             }