From a82590c276aa60de5374f831a2d300a11ba9e812 Mon Sep 17 00:00:00 2001
From: KrakenTyio <svidran@plusnet.sk>
Date: Fri, 21 Nov 2025 09:59:17 +0100
Subject: [PATCH 1/2] Modify missedPackets to include entry ID

restore messages contain actual entry ID to correct client offset
---
 lib/adapter.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/adapter.ts b/lib/adapter.ts
index 17f082a..773d64b 100644
--- a/lib/adapter.ts
+++ b/lib/adapter.ts
@@ -293,8 +293,10 @@ class RedisStreamsAdapter extends ClusterAdapterWithHeartbeat {
 
           // @ts-ignore
           if (shouldIncludePacket(session.rooms, message.data.opts)) {
+            const packetData = message.data.packet.data.slice();
+            packetData.push(entry.id);
             // @ts-ignore
-            session.missedPackets.push(message.data.packet.data);
+            session.missedPackets.push(packetData);
           }
         }
         offset = entry.id;

From af8d6443a8560cfda29fa6da660d6d97f99862d2 Mon Sep 17 00:00:00 2001
From: Damien Arrachequesne <damien.arrachequesne@gmail.com>
Date: Tue, 25 Nov 2025 10:45:49 +0100
Subject: [PATCH 2/2] test: add test

---
 lib/adapter.ts                    | 16 ++++++++--------
 test/connection-state-recovery.ts | 12 ++++++++++--
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/lib/adapter.ts b/lib/adapter.ts
index 773d64b..ceeffdc 100644
--- a/lib/adapter.ts
+++ b/lib/adapter.ts
@@ -289,14 +289,14 @@ class RedisStreamsAdapter extends ClusterAdapterWithHeartbeat {
 
       for (const entry of entries) {
         if (entry.message.nsp === this.nsp.name && entry.message.type === "3") {
-          const message = RedisStreamsAdapter.decode(entry.message);
-
-          // @ts-ignore
-          if (shouldIncludePacket(session.rooms, message.data.opts)) {
-            const packetData = message.data.packet.data.slice();
-            packetData.push(entry.id);
-            // @ts-ignore
-            session.missedPackets.push(packetData);
+          const message = RedisStreamsAdapter.decode(entry.message) as {
+            data: any;
+          };
+          const { packet, opts } = message.data;
+
+          if (shouldIncludePacket(session.rooms, opts)) {
+            packet.data.push(entry.id);
+            session.missedPackets.push(packet.data);
           }
         }
         offset = entry.id;
diff --git a/test/connection-state-recovery.ts b/test/connection-state-recovery.ts
index ee9eecc..6f9b643 100644
--- a/test/connection-state-recovery.ts
+++ b/test/connection-state-recovery.ts
@@ -1,10 +1,10 @@
 import { Server } from "socket.io";
 import { io as ioc } from "socket.io-client";
-import { setup, sleep } from "./util";
+import { setup } from "./util";
 import expect = require("expect.js");
 
 describe("connection state recovery", () => {
-  let servers: Server[], ports: number[], cleanup;
+  let servers: Server[], ports: number[], cleanup: () => void;
 
   beforeEach(async () => {
     const testContext = await setup({
@@ -82,10 +82,14 @@ describe("connection state recovery", () => {
       socket.io.engine.close();
 
       socket.on("connect", () => {
+        // @ts-expect-error _lastOffset is private
+        offsets.add(socket._lastOffset);
+
         expect(socket.recovered).to.eql(true);
 
         setTimeout(() => {
           expect(events).to.eql([1, 2, 3]);
+          expect(offsets.size).to.eql(4);
 
           socket.disconnect();
           done();
@@ -94,9 +98,13 @@ describe("connection state recovery", () => {
     });
 
     const events: number[] = [];
+    const offsets = new Set<string>();
 
     socket.on("myEvent", (val) => {
       events.push(val);
+      // note: the offset is updated after the callback execution
+      // @ts-expect-error _lastOffset is private
+      offsets.add(socket._lastOffset);
     });
   });