From 2392e3c7e2c482eb6bbdf333243ba93bf1c91c6f Mon Sep 17 00:00:00 2001
From: wanqifei <wanqifei@sankuai.com>
Date: Fri, 1 Nov 2024 17:32:44 +0800
Subject: [PATCH 1/3] fix: fix wrong length number write to packet

---
 lib/packets/packet.js | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/packets/packet.js b/lib/packets/packet.js
index 42241ae950..4a111180ff 100644
--- a/lib/packets/packet.js
+++ b/lib/packets/packet.js
@@ -830,11 +830,10 @@ class Packet {
     if (n === null) {
       return this.writeInt8(0xfb);
     }
-    // TODO: check that n is out of int precision
     this.writeInt8(0xfe);
-    this.buffer.writeUInt32LE(n, this.offset);
+    this.buffer.writeUInt32LE(n & 0xffffffff, this.offset);
     this.offset += 4;
-    this.buffer.writeUInt32LE(n >> 32, this.offset);
+    this.buffer.writeUInt32LE(Math.floor(n / 0x100000000), this.offset);
     this.offset += 4;
     return this.offset;
   }

From 6c4d178e0efda3a64830a638d87855eed3e192d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Weslley=20Ara=C3=BAjo?=
 <46850407+wellwelwel@users.noreply.github.com>
Date: Sat, 21 Feb 2026 18:42:43 -0300
Subject: [PATCH 2/3] Update lib/packets/packet.js

---
 lib/packets/packet.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/packets/packet.js b/lib/packets/packet.js
index 12ec033775..7d9673298b 100644
--- a/lib/packets/packet.js
+++ b/lib/packets/packet.js
@@ -832,7 +832,7 @@ class Packet {
       return this.writeInt8(0xfb);
     }
     this.writeInt8(0xfe);
-    this.buffer.writeUInt32LE(n & 0xffffffff, this.offset);
+    this.buffer.writeUInt32LE(n >>> 0, this.offset);
     this.offset += 4;
     this.buffer.writeUInt32LE(Math.floor(n / 0x100000000), this.offset);
     this.offset += 4;

From 408bd0440bbca0900f9759a7bf0817e330b1dda8 Mon Sep 17 00:00:00 2001
From: wellwelwel <46850407+wellwelwel@users.noreply.github.com>
Date: Sat, 21 Feb 2026 18:49:28 -0300
Subject: [PATCH 3/3] ci: add tests

---
 .../packets/test-length-coded-number.test.mts | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 test/unit/packets/test-length-coded-number.test.mts

diff --git a/test/unit/packets/test-length-coded-number.test.mts b/test/unit/packets/test-length-coded-number.test.mts
new file mode 100644
index 0000000000..0356aa3511
--- /dev/null
+++ b/test/unit/packets/test-length-coded-number.test.mts
@@ -0,0 +1,41 @@
+import { assert, describe, it } from 'poku';
+import Packet from '../../../lib/packets/packet.js';
+
+describe('writeLengthCodedNumber / readLengthCodedNumber roundtrip', () => {
+  const roundtrip = (n: number): number | null => {
+    const size = 4 + Packet.lengthCodedNumberLength(n);
+    const buffer = Buffer.alloc(size);
+    const packet = new Packet(0, buffer, 0, size);
+
+    packet.writeLengthCodedNumber(n);
+    packet.offset = 4;
+
+    return packet.readLengthCodedNumber();
+  };
+
+  it('should roundtrip values in the 1-byte range', () => {
+    assert.strictEqual(roundtrip(0), 0);
+    assert.strictEqual(roundtrip(250), 250);
+  });
+
+  it('should roundtrip values in the 2-byte range (0xFC tag)', () => {
+    assert.strictEqual(roundtrip(251), 251);
+    assert.strictEqual(roundtrip(0xfffe), 0xfffe);
+  });
+
+  it('should roundtrip values in the 3-byte range (0xFD tag)', () => {
+    assert.strictEqual(roundtrip(0xffff), 0xffff);
+    assert.strictEqual(roundtrip(0xfffffe), 0xfffffe);
+  });
+
+  it('should roundtrip values >= 0xFFFFFF in the 8-byte range (0xFE tag)', () => {
+    assert.strictEqual(roundtrip(0xffffff), 0xffffff);
+    assert.strictEqual(roundtrip(0x2000000), 0x2000000); // 32MB: PR #3177
+    assert.strictEqual(roundtrip(0xffffffff), 0xffffffff);
+  });
+
+  it('should roundtrip values above 32-bit range', () => {
+    assert.strictEqual(roundtrip(0x100000001), 0x100000001);
+    assert.strictEqual(roundtrip(0x1ffffffffff), 2199023255551);
+  });
+});