Function launchDetachedInstall

packages/cli/src/utils/autoUpdate.ts:77–118

* Spawn a detached child to run the install command. Stdout/stderr land in * the log file; the child is `unref()`d so the parent exits immediately * regardless of install duration. * * The child is responsible for writing `completedUpdate` to the config when * it finishes — we express that by r

(installCommand: string, version: string)

 * one spawned process with no extra binary to distribute.
 */
function launchDetachedInstall(installCommand: string, version: string): void {
  mkdirSync(CONFIG_DIR, { recursive: true, mode: 0o700 });
  const configFile = join(CONFIG_DIR, "config.json");

  // The child script:
  //   1. Runs the install command, capturing exit code + stderr tail.
  //   2. Rewrites the config file with completedUpdate, clears pendingUpdate.
  // We shell out to `node -e` so we don't need to ship a separate file.
  const nodeScript = `
    const { exec } = require("node:child_process");
    const { readFileSync, renameSync, writeFileSync } = require("node:fs");
    const CFG = ${JSON.stringify(configFile)};
    const TMP = \`\${CFG}.tmp\`;
    const VERSION = ${JSON.stringify(version)};
    const CMD = ${JSON.stringify(installCommand)};
    exec(CMD, { windowsHide: true, maxBuffer: 4 * 1024 * 1024 }, (err, _stdout, stderr) => {
      let cfg = {};
      try { cfg = JSON.parse(readFileSync(CFG, "utf-8")); } catch (e) {}
      cfg.completedUpdate = {
        version: VERSION,
        ok: !err,
        finishedAt: new Date().toISOString(),
        ...(err ? { error: String(stderr || err.message || "install failed").slice(-400) } : {}),
      };
      delete cfg.pendingUpdate;
      try {
        writeFileSync(TMP, JSON.stringify(cfg, null, 2) + "\\n", { mode: 0o600 });
        renameSync(TMP, CFG);
      } catch (e) {}
    });
  `;

  const out = openSync(LOG_FILE, "a", 0o600);
  const child = spawn(process.execPath, ["-e", nodeScript], {
    detached: true,
    stdio: ["ignore", out, out],
    windowsHide: true,
    env: { ...process.env, HYPERFRAMES_NO_UPDATE_CHECK: "1", HYPERFRAMES_NO_AUTO_INSTALL: "1" },
  });
  child.unref();
  log(`[launch] pid=${child.pid ?? "?"} cmd=${installCommand} version=${version}`);
}

/**
 * If a new version is available and policy allows, kick off a detached