fix(desktop): prevent WSL backend exiting with code 0 by keeping stdi…

[jibin7jose]

…n open

Fixes #3611 by appending Stream.never to the bootstrap stream so the Windows-side pipe does not close before the backend process completes reading it.

What Changed

Why

UI Changes

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

---

Note

Medium Risk
Touches desktop backend spawn/restart lifecycle and WSL preflight gating; changes are scoped but affect when the app falls back from WSL and how bootstrap is read over stdin.

Overview
Fixes WSL backends exiting with code 0 right after bootstrap by appending Stream.never to the stdin bootstrap stream so the Windows-side pipe stays open until the child finishes reading the envelope (stdin-delivery only; fd3 Windows-native unchanged).

Adds a neverReadyAttempt counter for stdin-delivery backends that tracks consecutive exits before HTTP readiness. After MAX_PREFLIGHT_FAILURE_ATTEMPTS, the manager calls onPreflightFailed and stops or restarts based on its result instead of looping forever; successful readiness resets the counter.

WSL preflight now prints nodeVersion: from the node-pty probe and parseNodeVersion validates it against nodeEngineRange, failing fast with a fatal, actionable error when Node is missing or incompatible.

Server readBootstrapEnvelope registers the error listener on the readline interface (not the raw stream) and runs cleanup on error, line, and close so early stream errors are handled consistently.

^{Reviewed by Cursor Bugbot for commit 0b8f928. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Fix WSL backend exiting prematurely by keeping stdin open for stdin-delivery backends

• For stdin-delivery backends (e.g. WSL), stdin is now kept open after writing the bootstrap JSON by appending Stream.never, preventing the child process from exiting with code 0 immediately after receiving its envelope.
• Consecutive exits before HTTP readiness are now tracked via a neverReadyAttempt counter; after MAX_PREFLIGHT_FAILURE_ATTEMPTS, onPreflightFailed is invoked and the manager stops or restarts based on its result rather than restarting indefinitely.
• The WSL node-pty probe script now emits the detected Node.js version on a nodeVersion: line; ensureNodePtyImpl validates this against a supplied semver range and returns { ok: false, fatal: true } when the version is missing or out of range.
• Error handling in readBootstrapEnvelope is fixed to register the error listener on the readline interface rather than the raw stream, ensuring cleanup runs on all error paths.

^{Macroscope summarized 0b8f928.}

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on this repository. Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: eab09290-c4e9-465f-9f0f-2d14deb84332

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[macroscopeapp]

Approvability

Verdict: Needs human review

This PR introduces new runtime behavior for WSL backend lifecycle: stdin stream handling changes, new failure tracking with fallback logic after consecutive never-ready exits, and Node.js version validation. These are meaningful behavioral changes to backend management that warrant human review.

^{You can customize Macroscope's approvability policy. Learn more.}

Dismissing prior approval to re-evaluate 215bd10

[jibin7jose]

@juliusmarminge Could you please approve the workflows for this PR so the checks can run? Thank you!

[jibin7jose]

Hi @juliusmarminge! When you have time, could you please take a look at this PR? It addresses issue #3611 by fixing the WSL backend exiting early when using stdin bootstrap delivery. I’ve incorporated the follow-up fixes and kept the PR up to date with main. If you have any feedback or would like any changes, I’d be happy to update the PR. Thank you!

[jibin7jose]

Hi @juliusmarminge, @t3dotgg, and @codex! When you have a chance, could you please take a look at this PR? It fixes the WSL backend exiting early when using stdin bootstrap delivery, includes the follow-up fixes from earlier feedback, and has been kept up to date with main. Once the workflows are approved and the checks complete, I'd really appreciate your review. Thank you!

[chatgpt-codex-connector]

To use Codex here, create a Codex account and connect to github.