From d4f7fbc718a86d0f76abba09228a383ac73e639a Mon Sep 17 00:00:00 2001
From: mikewong23571 <mikewong23571@gmail.com>
Date: Fri, 13 Mar 2026 03:15:35 +0800
Subject: [PATCH] fix: align native daemon port hash with client on Windows
 (#734)
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The client (connection.rs) and native daemon (native/daemon.rs) used
different get_port_for_session() implementations on Windows:

- Client:  i32, .chars(), djb2  — (hash << 5) - hash + c
- Daemon:  i64, .bytes(), Java hashCode — hash * 31 + b

For session name "default", client computes port 50838 while the
daemon binds on 51174, causing a 5-second timeout and startup failure.

Fix: align native/daemon.rs to use the identical djb2 algorithm from
connection.rs (i32, chars, djb2), so both sides agree on the port.

Unix is unaffected (uses Unix domain sockets, no port hashing).

Tests: add port hash regression tests to all three implementations
(native/daemon.rs, connection.rs, daemon.ts) to prevent future drift.

Fixes #705
---
 cli/src/connection.rs    |  9 +++++++++
 cli/src/native/daemon.rs | 25 +++++++++++++++++++++----
 src/daemon.test.ts       | 25 ++++++++++++++++++++++++-
 src/daemon.ts            |  2 +-
 4 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/cli/src/connection.rs b/cli/src/connection.rs
index dfd064a..f6ce676 100644
--- a/cli/src/connection.rs
+++ b/cli/src/connection.rs
@@ -792,4 +792,13 @@ mod tests {
         assert!(!is_transient_error("Permission denied"));
         assert!(!is_transient_error("Daemon not found"));
     }
+
+    #[test]
+    #[cfg(windows)]
+    fn test_get_port_for_session() {
+        assert_eq!(get_port_for_session("default"), 50838);
+        assert_eq!(get_port_for_session("my-session"), 63105);
+        assert_eq!(get_port_for_session("work"), 51184);
+        assert_eq!(get_port_for_session(""), 49152);
+    }
 }
diff --git a/cli/src/native/daemon.rs b/cli/src/native/daemon.rs
index 464be34..3d2bfc3 100644
--- a/cli/src/native/daemon.rs
+++ b/cli/src/native/daemon.rs
@@ -258,9 +258,26 @@ fn get_daemon_socket_dir() -> PathBuf {
 
 #[cfg(windows)]
 fn get_port_for_session(session: &str) -> u16 {
-    let mut hash: i64 = 0;
-    for b in session.bytes() {
-        hash = hash.wrapping_mul(31).wrapping_add(b as i64);
+    let mut hash: i32 = 0;
+    for c in session.chars() {
+        hash = ((hash << 5).wrapping_sub(hash)).wrapping_add(c as i32);
+    }
+    49152 + ((hash.unsigned_abs() as u32 % 16383) as u16)
+}
+
+#[cfg(test)]
+#[cfg(windows)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_port_matches_client_algorithm() {
+        // These values are computed by the identical djb2 implementation in
+        // connection.rs. Both sides must agree on the port for the daemon to
+        // start successfully.
+        assert_eq!(get_port_for_session("default"), 50838);
+        assert_eq!(get_port_for_session("my-session"), 63105);
+        assert_eq!(get_port_for_session("work"), 51184);
+        assert_eq!(get_port_for_session(""), 49152);
     }
-    49152 + (hash.unsigned_abs() % 16383) as u16
 }
diff --git a/src/daemon.test.ts b/src/daemon.test.ts
index bdafc0b..7ffcd1d 100644
--- a/src/daemon.test.ts
+++ b/src/daemon.test.ts
@@ -3,7 +3,7 @@ import * as os from 'os';
 import * as path from 'path';
 import * as net from 'net';
 import { EventEmitter } from 'events';
-import { getSocketDir, safeWrite } from './daemon.js';
+import { getSocketDir, safeWrite, getPortForSession } from './daemon.js';
 
 /**
  * HTTP request detection pattern used in daemon.ts to prevent cross-origin attacks.
@@ -159,3 +159,26 @@ describe('safeWrite', () => {
     expect(socket.listenerCount('close')).toBe(0);
   });
 });
+
+describe('getPortForSession', () => {
+  it('returns consistent port for "default"', () => {
+    expect(getPortForSession('default')).toBe(50838);
+  });
+
+  it('returns consistent port for named sessions', () => {
+    expect(getPortForSession('my-session')).toBe(63105);
+    expect(getPortForSession('work')).toBe(51184);
+  });
+
+  it('returns base port for empty session', () => {
+    expect(getPortForSession('')).toBe(49152);
+  });
+
+  it('returns port within dynamic range (49152-65535)', () => {
+    for (const name of ['default', 'my-session', 'work', 'test', 'a']) {
+      const port = getPortForSession(name);
+      expect(port).toBeGreaterThanOrEqual(49152);
+      expect(port).toBeLessThanOrEqual(65535);
+    }
+  });
+});
diff --git a/src/daemon.ts b/src/daemon.ts
index 220b2e9..cfa6cc1 100644
--- a/src/daemon.ts
+++ b/src/daemon.ts
@@ -185,7 +185,7 @@ export function getSession(): string {
  * Get port number for TCP mode (Windows)
  * Uses a hash of the session name to get a consistent port
  */
-function getPortForSession(session: string): number {
+export function getPortForSession(session: string): number {
   let hash = 0;
   for (let i = 0; i < session.length; i++) {
     hash = (hash << 5) - hash + session.charCodeAt(i);