From cb352a1c5a816c967f8717296b8ff9a856d63401 Mon Sep 17 00:00:00 2001
From: vheun <vheun@icloud.com>
Date: Mon, 3 Aug 2026 16:03:37 -0400
Subject: [PATCH] Release the NB gc timer when an incoming socket closes

enhance() starts a 10s interval to time out stalled transfers and only
unref()s it. unref keeps the timer from holding the process open, but
the Timeout stays in Node's timer list - a GC root - so the interval's
closure pinned nb, sched, opts and the socket itself, with all its
eventCallbacks and the dead net.Socket. Every WebSocket a server ever
accepted stayed in the heap.

Measured against a real ToolSocket server, incoming sockets that
connect, subscribe and close: 19,035 B retained per connection at
N=200 and 17,417 B at N=600 - linear in connection count. With the
close handler: 1,862 B and 237 B, and the total falls from 372 KB to
142 KB between those runs, i.e. no longer proportional to N.

Guarded exactly like the pressure-registry entry above it: an
auto-reconnecting outgoing socket keeps its timer across reconnects,
while an incoming socket (url === null) can never reopen and releases
it. large_object_space and external deltas were zero throughout - this
is plain old-space retention.
---
 src/ToolSocketNB.js | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/ToolSocketNB.js b/src/ToolSocketNB.js
index 13926bde..1a76b319 100644
--- a/src/ToolSocketNB.js
+++ b/src/ToolSocketNB.js
@@ -814,7 +814,14 @@ function enhance(ts, userOpts = {}) {
             }
         }
     }, 10000);
+    // unref() keeps the timer from holding the process open, but it stays in
+    // the timer list - a GC root - so without this the interval's closure
+    // pins nb/sched/opts and the whole socket forever. Guarded exactly like
+    // the pressure entry above: an auto-reconnecting outgoing socket keeps
+    // its gc timer across reconnects, while an incoming socket (url === null)
+    // never comes back and must release it.
     if (gc.unref) gc.unref();
+    ts.addEventListener('close', () => { if (!(opts.reconnect && ts.url)) clearInterval(gc); });
 
     // ---------- public backpressure / flow-control API ----------
     ts.getBackpressure = () => sched.stats();