fix(login): continue when browser launch fails

[atyrode]

Refs #939

Context

clever login opens the Console login URL and then polls the OAuth endpoint. With open@10.2.0 and { wait: false }, open() returns a detached ChildProcess without installing an error listener.

On a packaged headless Linux/Nix installation without xdg-open:

$ nix shell nixpkgs#clever-tools --command clever login
Opening https://console.clever-cloud.com/cli-oauth?cli_version=4.11.0&cli_token=<redacted> in your browser to log you in…
node:events:497
      throw er; // Unhandled 'error' event
      ^

Error: spawn xdg-open ENOENT

In bundled Linux builds, if the system xdg-open is missing, the child emits an asynchronous ENOENT event. That event was unhandled, so Node terminated the CLI before OAuth polling could continue. Catching only the awaited open() call does not handle the later child-process event.

Solution

Handle both browser-launch failure paths at the existing login call site:

• catch synchronous throws and rejected opener promises;
• attach a one-time error listener to the returned child process;
• print a static warning asking the user to open the already-displayed URL manually;
• continue the existing OAuth polling flow.

The change remains local to login and preserves { wait: false }. It does not change polling, cancellation, authentication, timeouts, the shared browser helper, launcher exit-code handling, or process lifetime. The launch error is intentionally not logged because its spawn arguments can contain the credential-bearing login URL.

How to test

• npm run validate
• build the Rollup bundle and Linux pkg binary;
• run the packaged binary without xdg-open against loopback-only API and Console endpoints;
• verify the process remains alive and continues polling after the launcher error;
• verify a genuine polling failure still exits with code 1;
• verify Ctrl+C still terminates promptly.

The packaged Linux reproduction passes. The original Windows report remains unverified; please add the build:win label so the reporter can test a Windows preview.

Optional regression coverage

Three dependency-free helper tests are available separately if maintainers want to adopt a test entry point. They are intentionally not part of this source-only PR:

• test-only diff against this fix
• optional test branch
• standalone test commit

[hsablonniere]

Thanks @atyrode, solid fix. I went and checked how a few other CLIs handle this case (gh, gcloud) and left some suggestions inline.

[atyrode]

Thanks! I applied both suggestions. GitHub’s batch application introduced mixed line endings in the changed block, so I added a formatting-only commit to normalize them. npm run validate passes.