Fix freebuff stale session takeover (#605)

Co-authored-by: James Grugett <jahooma@gmail.com>

Author: brandonkachen

cli/src/hooks/use-exit-handler.ts

@@ -3,6 +3,7 @@ import { useCallback, useEffect, useRef, useState } from 'react'
 import { getCurrentChatId } from '../project-files'
 import { flushAnalytics } from '../utils/analytics'
 import { IS_FREEBUFF } from '../utils/constants'
+import { exitFreebuffCleanly } from '../utils/freebuff-exit'
 import { withTimeout } from '../utils/terminal-color-detection'
 
 import type { InputValue } from '../types/store'
@@ -38,6 +39,19 @@ function setupExitMessageHandler() {
   })
 }
 
+function exitCli(): void {
+  if (IS_FREEBUFF) {
+    void exitFreebuffCleanly()
+    return
+  }
+
+  withTimeout(flushAnalytics(), EXIT_FLUSH_TIMEOUT_MS, undefined).finally(
+    () => {
+      process.exit(0)
+    },
+  )
+}
+
 export const useExitHandler = ({
   inputValue,
   setInputValue,
@@ -70,9 +84,7 @@ export const useExitHandler = ({
       exitWarningTimeoutRef.current = null
     }
 
-    withTimeout(flushAnalytics(), EXIT_FLUSH_TIMEOUT_MS, undefined).then(() => {
-      process.exit(0)
-    })
+    exitCli()
     return true
   }, [inputValue, setInputValue, nextCtrlCWillExit])
 
@@ -83,11 +95,7 @@ export const useExitHandler = ({
         exitWarningTimeoutRef.current = null
       }
 
-      withTimeout(flushAnalytics(), EXIT_FLUSH_TIMEOUT_MS, undefined).finally(
-        () => {
-          process.exit(0)
-        },
-      )
+      exitCli()
     }
 
     process.on('SIGINT', handleSigint)

cli/src/hooks/use-freebuff-session.ts

@@ -12,6 +12,10 @@ import {
 import { useFreebuffSessionStore } from '../state/freebuff-session-store'
 import { getAuthTokenDetails } from '../utils/auth'
 import { IS_FREEBUFF } from '../utils/constants'
+import {
+  isFreebuffInstanceOwnedByDeadLocalProcess,
+  recordFreebuffInstanceOwner,
+} from '../utils/freebuff-instance-owner'
 import { logger } from '../utils/logger'
 import { saveFreebuffModelPreference } from '../utils/settings'
 
@@ -363,9 +367,9 @@ interface UseFreebuffSessionResult {
  * Manages the freebuff waiting-room session lifecycle:
  *   - GET on mount to probe state (no auto-join; the user picks a model in
  *     the landing screen, which calls joinFreebuffQueue)
- *   - if the probe sees an existing seat, asks before POSTing to take over
- *     (rotates the instance id so any other CLI on the same account is
- *     superseded)
+ *   - if the probe sees an existing seat, auto-takes-over when the prior
+ *     local owner process is gone; otherwise asks before POSTing to rotate
+ *     the instance id so any other CLI on the same account is superseded
  *   - polls GET while queued (fast) or active (slow) to keep state fresh
  *   - re-POSTs on explicit refresh (chat gate rejected us, user switched
  *     models, user rejoined after ending)
@@ -406,6 +410,9 @@ export function useFreebuffSession(): UseFreebuffSessionResult {
     let nextMethod: 'GET' | 'POST' = 'GET'
 
     const apply = (next: FreebuffSessionResponse) => {
+      if (next.status === 'queued' || next.status === 'active') {
+        recordFreebuffInstanceOwner(next.instanceId)
+      }
       setSession(next)
       setError(null)
       previousStatus = next.status
@@ -479,6 +486,14 @@ export function useFreebuffSession(): UseFreebuffSessionResult {
           (next.status === 'queued' || next.status === 'active')
         ) {
           useFreebuffModelStore.getState().setSelectedModel(next.model)
+          // A fast restart after Ctrl+C can observe the old server row before
+          // best-effort DELETE lands. If the row belongs to a dead local
+          // process, silently do the same POST as the Take over button.
+          if (isFreebuffInstanceOwnedByDeadLocalProcess(next.instanceId)) {
+            nextMethod = 'POST'
+            schedule(0)
+            return
+          }
           apply({ status: 'takeover_prompt', model: next.model })
           return
         }

cli/src/utils/__tests__/freebuff-instance-owner.test.ts

@@ -0,0 +1,69 @@
+import fs from 'fs'
+import os from 'os'
+import path from 'path'
+
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
+
+import { ensureCliTestEnv } from '../../__tests__/test-utils'
+
+const OWNER_FILE = 'freebuff-instance-owner.json'
+
+ensureCliTestEnv()
+
+const { getConfigDir } = await import('../auth')
+const {
+  isFreebuffInstanceOwnedByDeadLocalProcess,
+  recordFreebuffInstanceOwner,
+} = await import('../freebuff-instance-owner')
+
+describe('freebuff instance owner', () => {
+  let originalHome: string | undefined
+  let tempHome: string
+
+  const ownerPath = () => path.join(getConfigDir(), OWNER_FILE)
+
+  beforeEach(() => {
+    originalHome = process.env.HOME
+    tempHome = fs.mkdtempSync(path.join(os.tmpdir(), 'freebuff-owner-'))
+    process.env.HOME = tempHome
+  })
+
+  afterEach(() => {
+    if (originalHome === undefined) {
+      delete process.env.HOME
+    } else {
+      process.env.HOME = originalHome
+    }
+    fs.rmSync(tempHome, { recursive: true, force: true })
+  })
+
+  test('does not classify the current process as dead', () => {
+    recordFreebuffInstanceOwner('inst-current')
+
+    expect(
+      isFreebuffInstanceOwnedByDeadLocalProcess('inst-current'),
+    ).toBe(false)
+  })
+
+  test('classifies a matching owner with a dead pid as dead', () => {
+    fs.mkdirSync(getConfigDir(), { recursive: true })
+    fs.writeFileSync(
+      ownerPath(),
+      JSON.stringify({ instanceId: 'inst-dead', pid: 2_147_483_647 }),
+    )
+
+    expect(isFreebuffInstanceOwnedByDeadLocalProcess('inst-dead')).toBe(true)
+  })
+
+  test('ignores a dead pid for a different instance id', () => {
+    fs.mkdirSync(getConfigDir(), { recursive: true })
+    fs.writeFileSync(
+      ownerPath(),
+      JSON.stringify({ instanceId: 'inst-other', pid: 2_147_483_647 }),
+    )
+
+    expect(
+      isFreebuffInstanceOwnedByDeadLocalProcess('inst-current'),
+    ).toBe(false)
+  })
+})

cli/src/utils/freebuff-instance-owner.ts

@@ -0,0 +1,66 @@
+import fs from 'fs'
+import path from 'path'
+
+import { getConfigDir } from './auth'
+import { logger } from './logger'
+
+interface FreebuffInstanceOwner {
+  instanceId: string
+  pid: number
+}
+
+const OWNER_FILE = 'freebuff-instance-owner.json'
+
+const getOwnerPath = (): string => path.join(getConfigDir(), OWNER_FILE)
+
+function readOwner(): FreebuffInstanceOwner | null {
+  try {
+    const raw = fs.readFileSync(getOwnerPath(), 'utf8')
+    const parsed = JSON.parse(raw) as Partial<FreebuffInstanceOwner>
+    if (
+      typeof parsed.instanceId !== 'string' ||
+      typeof parsed.pid !== 'number'
+    ) {
+      return null
+    }
+    return {
+      instanceId: parsed.instanceId,
+      pid: parsed.pid,
+    }
+  } catch {
+    return null
+  }
+}
+
+function isProcessRunning(pid: number): boolean {
+  if (!Number.isInteger(pid) || pid <= 0) return false
+  try {
+    process.kill(pid, 0)
+    return true
+  } catch (error) {
+    return (error as NodeJS.ErrnoException).code === 'EPERM'
+  }
+}
+
+export function recordFreebuffInstanceOwner(instanceId: string): void {
+  try {
+    fs.mkdirSync(getConfigDir(), { recursive: true })
+    fs.writeFileSync(
+      getOwnerPath(),
+      JSON.stringify({ instanceId, pid: process.pid }, null, 2),
+    )
+  } catch (error) {
+    logger.debug(
+      { error: error instanceof Error ? error.message : String(error) },
+      '[freebuff-session] Failed to record local owner',
+    )
+  }
+}
+
+export function isFreebuffInstanceOwnedByDeadLocalProcess(
+  instanceId: string,
+): boolean {
+  const owner = readOwner()
+  if (!owner || owner.instanceId !== instanceId) return false
+  return !isProcessRunning(owner.pid)
+}