From 3ff553549a4c10ce7154db6b516e362631045586 Mon Sep 17 00:00:00 2001
From: Florian Schmaus <flo@geekplace.eu>
Date: Wed, 2 Feb 2022 12:44:04 +0100
Subject: [PATCH] [SmackFuture] Invoke the callbacks at most once

Previously, if a SmackFuture both was successful and unsuccessful, it
was possible that the onSuccess() callback was invoked twice.

Reported-by: Boris Grozev <boris@jitsi.org>
---
 .../src/main/java/org/jivesoftware/smack/SmackFuture.java  | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/smack-core/src/main/java/org/jivesoftware/smack/SmackFuture.java b/smack-core/src/main/java/org/jivesoftware/smack/SmackFuture.java
index 08646728a..ec99e6c4a 100644
--- a/smack-core/src/main/java/org/jivesoftware/smack/SmackFuture.java
+++ b/smack-core/src/main/java/org/jivesoftware/smack/SmackFuture.java
@@ -162,16 +162,20 @@ public abstract class SmackFuture<V, E extends Exception> implements Future<V>,
         return result;
     }
 
+    private boolean callbacksInvoked;
+
     protected final synchronized void maybeInvokeCallbacks() {
-        if (cancelled) {
+        if (cancelled || callbacksInvoked) {
             return;
         }
 
         if ((result != null || exception != null) && completionCallback != null) {
+            callbacksInvoked = true;
             completionCallback.accept(this);
         }
 
         if (result != null && successCallback != null) {
+            callbacksInvoked = true;
             AbstractXMPPConnection.asyncGo(new Runnable() {
                 @Override
                 public void run() {
@@ -180,6 +184,7 @@ public abstract class SmackFuture<V, E extends Exception> implements Future<V>,
             });
         }
         else if (exception != null && exceptionCallback != null) {
+            callbacksInvoked = true;
             AbstractXMPPConnection.asyncGo(new Runnable() {
                 @Override
                 public void run() {