From b6e5e1277020b160e44e99cdedd8963e5c1c105e Mon Sep 17 00:00:00 2001
From: dvdrw <admin@dvdrw.dev>
Date: Tue, 9 Jun 2026 19:49:03 +0200
Subject: [PATCH] fix: deadlock when connecting/receiving connections rapidly

---
 src/Control/Actor/Network.hs | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/Control/Actor/Network.hs b/src/Control/Actor/Network.hs
index 0b3cb21..e0a65f2 100644
--- a/src/Control/Actor/Network.hs
+++ b/src/Control/Actor/Network.hs
@@ -29,8 +29,10 @@ import Control.Concurrent.STM
   , readTMVar
   , readTVar
   , readTVarIO
+  , tryPutTMVar
   , tryTakeTMVar
   , writeTQueue
+  , writeTVar
   )
 import Control.Exception (SomeException, try)
 import Control.Monad (forM_, forever, unless, void)
@@ -112,7 +114,7 @@ handleNewConn ch = do
           Nothing -> return ()
           Just p  -> do
             modifyTVar (rtConnPromises rt) (Map.delete peerAddr)
-            putTMVar p ref
+            void $ tryPutTMVar p ref
     _else -> liftIO $ chClose ch
 
 -- Connection pool
@@ -140,9 +142,11 @@ getOrCreateConn peer = do
       liftIO $ chSend ch (encode (NMHandshake (rtNodeId rt)))
       ref <- spawnConnTree peer ch
       liftIO $ atomically $ do
-        modifyTVar (rtConnections rt) (Map.insert peer ref)
+        conns <- readTVar (rtConnections rt)
+        unless (Map.member peer conns) $
+          modifyTVar (rtConnections rt) (Map.insert peer ref)
         modifyTVar (rtConnPromises rt) (Map.delete peer)
-        putTMVar promise ref
+        void $ tryPutTMVar promise ref
       return ref
 
 -- Message dispatch