From 2eb311938665f92ef48e2cfa030720fc68ca7cc9 Mon Sep 17 00:00:00 2001
From: Marvin W <git@larma.de>
Date: Fri, 23 Oct 2026 16:38:04 +0200
Subject: xmpp-vala: Fix deadlocks with cancellables

---
 xmpp-vala/src/module/iq/module.vala                | 31 +++++++++++++++++-----
 .../src/module/xep/0047_in_band_bytestreams.vala   |  4 +--
 2 files changed, 26 insertions(+), 9 deletions(-)

(limited to 'xmpp-vala/src/module')

diff --git a/xmpp-vala/src/module/iq/module.vala b/xmpp-vala/src/module/iq/module.vala
index 917f6660..c87db897 100644
--- a/xmpp-vala/src/module/iq/module.vala
+++ b/xmpp-vala/src/module/iq/module.vala
@@ -17,22 +17,39 @@ namespace Xmpp.Iq {
 
             preprocess_outgoing_iq_set_get(stream, iq);
             Iq.Stanza? return_stanza = null;
+            IOError? return_error = null;
+            bool yielded = false;
             responseListeners[iq.id] = new ResponseListener((_, result_iq) => {
                 return_stanza = result_iq;
-                if (cancellable == null || !cancellable.is_cancelled()) {
-                    Idle.add(send_iq_async.callback);
+                if (yielded) send_iq_async.callback();
+            });
+            stream.write_async.begin(iq.stanza, io_priority, cancellable, (_, res) => {
+                try {
+                    stream.write_async.end(res);
+                } catch (IOError e) {
+                    return_error = e;
                 }
             });
-            yield stream.write_async(iq.stanza, io_priority, cancellable);
             ulong cancelled_handler_id = 0;
             if (cancellable != null) {
-                cancelled_handler_id = cancellable.cancelled.connect(() => Idle.add(send_iq_async.callback));
+                cancelled_handler_id = cancellable.connect(() => {
+                    if (yielded) send_iq_async.callback();
+                });
+            }
+            if ((cancellable == null || !cancellable.is_cancelled()) && return_error == null) {
+                yielded = true;
+                yield;
+                yielded = false;
             }
-            yield;
             if (cancellable != null) {
-                cancellable.disconnect(cancelled_handler_id);
-                cancellable.set_error_if_cancelled();
+                if (cancellable.is_cancelled()) {
+                    cancellable.set_error_if_cancelled();
+                } else {
+                    cancellable.disconnect(cancelled_handler_id);
+                }
             }
+            responseListeners.unset(iq.id);
+            if (return_error != null) throw return_error;
             return return_stanza;
         }
 
diff --git a/xmpp-vala/src/module/xep/0047_in_band_bytestreams.vala b/xmpp-vala/src/module/xep/0047_in_band_bytestreams.vala
index 1e423b49..74034a8a 100644
--- a/xmpp-vala/src/module/xep/0047_in_band_bytestreams.vala
+++ b/xmpp-vala/src/module/xep/0047_in_band_bytestreams.vala
@@ -177,7 +177,7 @@ public class Connection : IOStream {
         if (read_callback != null) {
             Idle.add((owned) read_callback, read_callback_priority);
             read_callback = null;
-            if (read_callback_cancellable != null) {
+            if (read_callback_cancellable != null && !read_callback_cancellable.is_cancelled()) {
                 read_callback_cancellable.disconnect(read_callback_cancellable_id);
             }
             read_callback_cancellable = null;
@@ -187,7 +187,7 @@ public class Connection : IOStream {
         if (write_callback != null) {
             Idle.add((owned) write_callback, write_callback_priority);
             write_callback = null;
-            if (write_callback_cancellable != null) {
+            if (write_callback_cancellable != null && !write_callback_cancellable.is_cancelled()) {
                 write_callback_cancellable.disconnect(write_callback_cancellable_id);
             }
             write_callback_cancellable = null;
-- 
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