From 863d0bf4032bba1b9199b8aa1a68981f2ed2fdc1 Mon Sep 17 00:00:00 2001
From: Florian Schmaus <flo@geekplace.eu>
Date: Mon, 9 Mar 2020 14:41:52 +0100
Subject: [PATCH] Fix NPE in ServiceDiscoveryManager

---
 .../java/org/jivesoftware/smack/packet/StanzaBuilder.java | 8 ++++++++
 .../smackx/disco/ServiceDiscoveryManager.java             | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/smack-core/src/main/java/org/jivesoftware/smack/packet/StanzaBuilder.java b/smack-core/src/main/java/org/jivesoftware/smack/packet/StanzaBuilder.java
index 3539d22bd..cff077e29 100644
--- a/smack-core/src/main/java/org/jivesoftware/smack/packet/StanzaBuilder.java
+++ b/smack-core/src/main/java/org/jivesoftware/smack/packet/StanzaBuilder.java
@@ -162,6 +162,14 @@ public abstract class StanzaBuilder<B extends StanzaBuilder<B>> implements Stanz
         return getThis();
     }
 
+    public final B addOptExtensions(Collection<? extends ExtensionElement> extensionElements) {
+        if (extensionElements == null) {
+            return getThis();
+        }
+
+        return addExtensions(extensionElements);
+    }
+
     public final B addExtensions(Collection<? extends ExtensionElement> extensionElements) {
         for (ExtensionElement extensionElement : extensionElements) {
             addExtension(extensionElement);
diff --git a/smack-extensions/src/main/java/org/jivesoftware/smackx/disco/ServiceDiscoveryManager.java b/smack-extensions/src/main/java/org/jivesoftware/smackx/disco/ServiceDiscoveryManager.java
index 62fc38d1d..a009d260b 100644
--- a/smack-extensions/src/main/java/org/jivesoftware/smackx/disco/ServiceDiscoveryManager.java
+++ b/smack-extensions/src/main/java/org/jivesoftware/smackx/disco/ServiceDiscoveryManager.java
@@ -178,7 +178,7 @@ public final class ServiceDiscoveryManager extends Manager {
                         // Add node identities
                         responseBuilder.addIdentities(nodeInformationProvider.getNodeIdentities());
                         // Add packet extensions
-                        responseBuilder.addExtensions(nodeInformationProvider.getNodePacketExtensions());
+                        responseBuilder.addOptExtensions(nodeInformationProvider.getNodePacketExtensions());
                     } else {
                         // Return <item-not-found/> error since specified node was not found
                         responseBuilder.ofType(IQ.Type.error);