Function isLockActive

src/utils/nativeInstaller/pidLock.ts:164–205

(lockFilePath: string)

 * Check if a lock file represents an active lock (process still running)
 */
export function isLockActive(lockFilePath: string): boolean {
  const content = readLockContent(lockFilePath)

  if (!content) {
    return false
  }

  const { pid, execPath } = content

  // Primary check: is the process running?
  if (!isProcessRunning(pid)) {
    return false
  }

  // Secondary validation: is it actually a Claude process?
  // This helps with PID reuse scenarios
  if (!isClaudeProcess(pid, execPath)) {
    logForDebugging(
      `Lock PID ${pid} is running but does not appear to be Claude - treating as stale`,
    )
    return false
  }

  // Fallback: if the lock is very old (> 2 hours) and we can't validate
  // the command, be conservative and consider it potentially stale
  // This handles edge cases like network filesystems
  const fs = getFsImplementation()
  try {
    const stats = fs.statSync(lockFilePath)
    const age = Date.now() - stats.mtimeMs
    if (age > FALLBACK_STALE_MS) {
      // Double-check that we can still see the process
      if (!isProcessRunning(pid)) {
        return false
      }
    }
  } catch {
    // If we can't stat the file, trust the PID check
  }

  return true
}

/**
 * Write lock content to a file atomically