From 27cd59201dc60cf31d890637d8923d56ba5e1faf Mon Sep 17 00:00:00 2001
From: Neil <4138956+nwparker@users.noreply.github.com>
Date: Sat, 30 May 2026 05:26:39 -0700
Subject: [PATCH] fix: avoid daemon router reconcile spread crash

---
 src/main/daemon/daemon-pty-router.test.ts | 26 +++++++++++++++++++++++
 src/main/daemon/daemon-pty-router.ts      | 11 ++++++++--
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/main/daemon/daemon-pty-router.test.ts b/src/main/daemon/daemon-pty-router.test.ts
index 725a14c38d5..4c4d0ac0dfd 100644
--- a/src/main/daemon/daemon-pty-router.test.ts
+++ b/src/main/daemon/daemon-pty-router.test.ts
@@ -158,6 +158,32 @@ describe('DaemonPtyRouter', () => {
     expect(current.write).toHaveBeenCalledWith('current-alive', 'new\n')
   })
 
+  it('merges very large startup reconciliation results without dropping routes', async () => {
+    const currentAlive = Array.from({ length: 130_000 }, (_, index) => `current-alive-${index}`)
+    const legacyKilled = Array.from({ length: 130_000 }, (_, index) => `legacy-killed-${index}`)
+    const current = createAdapter('current', [], {
+      alive: currentAlive,
+      killed: []
+    })
+    const legacy = createAdapter('legacy', [], {
+      alive: ['legacy-alive'],
+      killed: legacyKilled
+    })
+    const router = new DaemonPtyRouter({ current, legacy: [legacy] })
+
+    const result = await router.reconcileOnStartup(new Set(['wt']))
+    router.write(currentAlive.at(-1)!, 'new\n')
+    router.write('legacy-alive', 'old\n')
+
+    expect(result.alive).toHaveLength(currentAlive.length + 1)
+    expect(result.alive[0]).toBe(currentAlive[0])
+    expect(result.alive.at(-1)).toBe('legacy-alive')
+    expect(result.killed).toHaveLength(legacyKilled.length)
+    expect(result.killed.at(-1)).toBe(legacyKilled.at(-1))
+    expect(current.write).toHaveBeenCalledWith(currentAlive.at(-1), 'new\n')
+    expect(legacy.write).toHaveBeenCalledWith('legacy-alive', 'old\n')
+  })
+
   it('disposes current and legacy adapters', () => {
     const current = createAdapter('current')
     const legacy = createAdapter('legacy')
diff --git a/src/main/daemon/daemon-pty-router.ts b/src/main/daemon/daemon-pty-router.ts
index e1668457b29..a0ec4cd51b3 100644
--- a/src/main/daemon/daemon-pty-router.ts
+++ b/src/main/daemon/daemon-pty-router.ts
@@ -1,6 +1,13 @@
 import type { DaemonPtyAdapter } from './daemon-pty-adapter'
 import type { IPtyProvider, PtySpawnOptions, PtySpawnResult } from '../providers/types'
 
+function appendSessionIds(target: string[], source: readonly string[]): void {
+  // Why: daemon restore can report enough sessions to exceed V8's spread-argument cap.
+  for (const id of source) {
+    target.push(id)
+  }
+}
+
 export class DaemonPtyRouter implements IPtyProvider {
   private current: DaemonPtyAdapter
   private legacy: DaemonPtyAdapter[]
@@ -175,8 +182,8 @@ export class DaemonPtyRouter implements IPtyProvider {
     const killed: string[] = []
     for (const adapter of this.allAdapters()) {
       const result = await adapter.reconcileOnStartup(validWorktreeIds)
-      alive.push(...result.alive)
-      killed.push(...result.killed)
+      appendSessionIds(alive, result.alive)
+      appendSessionIds(killed, result.killed)
       for (const id of result.alive) {
         this.sessionAdapters.set(id, adapter)
       }