Function appendFileSync

src/utils/fsOperations.ts:468–487

(path, data, options)

  },

  appendFileSync(path, data, options) {
    using _ = slowLogging`fs.appendFileSync(${path}, ${data.length} chars)`
    // For new files with explicit mode, use 'ax' (atomic create-with-mode) to avoid
    // TOCTOU race between existence check and open. Fall back to normal append if exists.
    if (options?.mode !== undefined) {
      try {
        const fd = fs.openSync(path, 'ax', options.mode)
        try {
          fs.appendFileSync(fd, data)
        } finally {
          fs.closeSync(fd)
        }
        return
      } catch (e) {
        if (getErrnoCode(e) !== 'EEXIST') throw e
        // File exists — fall through to normal append
      }
    }
    fs.appendFileSync(path, data)
  },

  copyFileSync(src, dest) {
    using _ = slowLogging`fs.copyFileSync(${src} → ${dest})`