Function startGlobalConfigFreshnessWatcher

src/utils/config.ts:1005–1042

()

// fs.watchFile polls stat on the libuv threadpool and only calls us when mtime
// changed — a stalled stat never blocks the main thread.
function startGlobalConfigFreshnessWatcher(): void {
  if (freshnessWatcherStarted || process.env.NODE_ENV === 'test') return
  freshnessWatcherStarted = true
  const file = getGlobalClaudeFile()
  watchFile(
    file,
    { interval: CONFIG_FRESHNESS_POLL_MS, persistent: false },
    curr => {
      // Our own writes fire this too — the write-through's Date.now()
      // overshoot makes cache.mtime > file mtime, so we skip the re-read.
      // Bun/Node also fire with curr.mtimeMs=0 when the file doesn't exist
      // (initial callback or deletion) — the <= handles that too.
      if (curr.mtimeMs <= globalConfigCache.mtime) return
      void getFsImplementation()
        .readFile(file, { encoding: 'utf-8' })
        .then(content => {
          // A write-through may have advanced the cache while we were reading;
          // don't regress to the stale snapshot watchFile stat'd.
          if (curr.mtimeMs <= globalConfigCache.mtime) return
          const parsed = safeParseJSON(stripBOM(content))
          if (parsed === null || typeof parsed !== 'object') return
          globalConfigCache = {
            config: migrateConfigFields({
              ...createDefaultGlobalConfig(),
              ...(parsed as Partial<GlobalConfig>),
            }),
            mtime: curr.mtimeMs,
          }
          lastReadFileStats = { mtime: curr.mtimeMs, size: curr.size }
        })
        .catch(() => {})
    },
  )
  registerCleanup(async () => {
    unwatchFile(file)
    freshnessWatcherStarted = false
  })
}

// Write-through: what we just wrote IS the new config. cache.mtime overshoots
// the file's real mtime (Date.now() is recorded after the write) so the