fix(core): suppress git stderr output in parseGitOutput

[FrozenPandaz]

Current Behavior

Since Nx 21.6.1, running nx graph or other commands that calculate affected projects prints git errors to stderr when the default branch is not fetched:

fatal: ambiguous argument 'main': unknown revision or path not in the working tree.

This causes CI pipelines with strict stderr checking to fail, even though the nx commands succeed.

Expected Behavior

Git error messages should not be printed to stderr. The errors are already caught and handled gracefully - they just shouldn't be visible to the user.

Related Issue(s)

Fixes #33330

Solution

Added stdio: 'pipe' to the execSync call in parseGitOutput(). This suppresses stderr output while still allowing the command to throw on failure (which is already caught by the try-catch in graph.ts).

This matches the pattern used in getMergeBase() which already uses stdio: 'pipe'.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Preview	Updated (UTC)
nx-dev	Ready	Preview	Nov 28, 2025 2:41pm

[netlify]

✅ Deploy Preview for nx-docs ready!

Name	Link
🔨 Latest commit	542a229
🔍 Latest deploy log	https://app.netlify.com/projects/nx-docs/deploys/6929b368bc69df000802e381
😎 Deploy Preview	https://deploy-preview-33645--nx-docs.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 542a229

Command	Status	Duration	Result
nx affected --targets=lint,test,test-kt,build,e...	✅ Succeeded	11m 6s	View ↗
nx run-many -t check-imports check-lock-files c...	✅ Succeeded	1m 46s	View ↗
nx-cloud record -- nx-cloud conformance:check	✅ Succeeded	11s	View ↗
nx-cloud record -- nx format:check	✅ Succeeded	2s	View ↗
nx-cloud record -- nx sync:check	✅ Succeeded	<1s	View ↗

---

☁️ Nx Cloud last updated this comment at 2025-11-28 14:52:27 UTC

[nx-cloud]

Important

A new CI pipeline execution was requested that may update the conclusion below...

Nx Cloud has identified a possible root cause for your failed CI:

Our test failures are unrelated to the stderr suppression changes. The e2e test failed due to an npm registry issue ("get-proto is not in the npm registry"), and the workspace test failed on Nuxt file generation. Neither failure involves the modified git output parsing code, and the npm registry issue requires external service recovery.

No code changes were suggested for this issue.

View detailed reasoning on Nx Cloud ↗

_{🎓 Learn more about Self-Healing CI on nx.dev}

[github-actions]

This pull request has already been merged/closed. If you experience issues related to these changes, please open a new issue referencing this pull request.