bug: superset auth login hangs silently on headless servers when xdg-open is missing #3949

Summary

superset auth login hangs forever on headless Linux servers (the typical CLI use case). The user sees only:

┌  superset auth login
│
◒  Waiting for browser authorization...

…and the spinner spins indefinitely with no actionable hint.

Reproduce

1. Install Superset CLI on a headless Linux box where xdg-open is not in $PATH (Hetzner ARM, AWS Graviton, Pi, vanilla Ubuntu Server, etc.).
2. Run superset auth login.
3. Observe: spinner runs, no URL printed, login never completes.

Root cause

packages/cli/src/lib/auth.ts:

async function openBrowser(url: string): Promise<void> {
  const { exec } = await import("node:child_process");
  switch (process.platform) {
    case "darwin": exec(`open "${url}"`); break;
    case "win32":  exec(`start "" "${url}"`); break;
    default:       exec(`xdg-open "${url}"`); break;
  }
}

exec(...) is fire-and-forget — its error is never observed. On systems without xdg-open it silently fails and the login URL is never surfaced.

Proposed fix

Surface the URL through a new optional onAuthUrl(url) callback on login(). The command layer prints it via p.log.info(...) right before the browser is launched — works on TTY (clack interleaves with the spinner) and headless alike. Browser auto-launch is unchanged for GUI users.

PR with the fix coming next.

Workaround until merged

mkdir -p /tmp/wrap
printf '%s\n' '#!/bin/bash' 'echo "AUTH_URL: $1"' > /tmp/wrap/xdg-open
chmod +x /tmp/wrap/xdg-open
PATH=/tmp/wrap:$PATH superset auth login

Then ssh -L 51789:localhost:51789 <host> from your workstation and paste the printed URL into your local browser; the OAuth loopback callback completes through the tunnel.

Related

• fix(cli): switch CLI auth to OAuth code + PKCE + loopback #3318 added the CLI's loopback OAuth flow.
• [feat] use in ssh server #1513 (use in ssh server) — fixing this URL-surfacing issue is a step toward making the CLI usable on headless boxes.