Function applySelfUpdate

src/update/self-update.ts:149–186

(target: UpdateTarget, currentBin: string)

}

export async function applySelfUpdate(target: UpdateTarget, currentBin: string): Promise<void> {
  const tmp = join(tmpdir(), `mmx-update-${Date.now()}`);

  process.stderr.write(`Downloading ${target.version}...\n`);
  let lastPct = -1;
  await downloadFile(target.downloadUrl, tmp, (pct) => {
    if (pct !== lastPct && pct % 10 === 0) {
      process.stderr.write(`  ${pct}%\r`);
      lastPct = pct;
    }
  });
  process.stderr.write('  \r');

  process.stderr.write('Verifying checksum...\n');
  await verifySha256(tmp, target.checksum);

  chmodSync(tmp, 0o755);

  // Atomic replace: rename works on same filesystem
  // If cross-device, fall back to copy+rename
  try {
    renameSync(tmp, currentBin);
  } catch {
    const { copyFileSync, unlinkSync } = await import('fs');
    const backup = `${currentBin}.bak`;
    copyFileSync(currentBin, backup);
    try {
      copyFileSync(tmp, currentBin);
      chmodSync(currentBin, 0o755);
      unlinkSync(tmp);
      if (existsSync(backup)) unlinkSync(backup);
    } catch (e) {
      // Restore backup
      if (existsSync(backup)) renameSync(backup, currentBin);
      throw e;
    }
  }
}