Function saveStatsCache

src/utils/statsCache.ts:214–254

(
  cache: PersistedStatsCache,
)

 * Uses a temp file + rename pattern to prevent corruption.
 */
export async function saveStatsCache(
  cache: PersistedStatsCache,
): Promise<void> {
  const fs = getFsImplementation()
  const cachePath = getStatsCachePath()
  const tempPath = `${cachePath}.${randomBytes(8).toString('hex')}.tmp`

  try {
    // Ensure the directory exists
    const configDir = getClaudeConfigHomeDir()
    try {
      await fs.mkdir(configDir)
    } catch {
      // Directory already exists or other error - proceed
    }

    // Write to temp file with fsync for atomic write safety
    const content = jsonStringify(cache, null, 2)
    const handle = await open(tempPath, 'w', 0o600)
    try {
      await handle.writeFile(content, { encoding: 'utf-8' })
      await handle.sync()
    } finally {
      await handle.close()
    }

    // Atomic rename
    await fs.rename(tempPath, cachePath)
    logForDebugging(
      `Stats cache saved successfully (lastComputedDate: ${cache.lastComputedDate})`,
    )
  } catch (error) {
    logError(error)
    // Clean up temp file
    try {
      await fs.unlink(tempPath)
    } catch {
      // Ignore cleanup errors
    }
  }
}

/**
 * Merge new stats into an existing cache.