fix: catch Exception in _flush_lines

[bennyz]

In case there are unexepected exceptions, to avoid hitting flakes https://github.com/jumpstarter-dev/jumpstarter/actions/runs/31179469197/attempts/1

[coderabbitai]

Warning

Review limit reached

@bennyz, you've reached your PR review limit, so we couldn't start this review.

Next review available in: 14 minutes

You've used all free OSS reviews for now. Wait for the free limit to reset to keep reviewing this public repository.

How can I continue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

To avoid repeated limits, reduce automatic review volume by pausing incremental auto-reviews earlier, using label-based review opt-in, excluding WIP or generated PR titles, or requesting reviews manually when the PR is ready. If your team needs uninterrupted high-volume reviews, an organization admin can enable usage-based reviews.

How do review limits work?

CodeRabbit enforces per-developer PR review limits for each organization. Most developers receive the normal plan review availability.

For paid Pro and Pro+ PR reviews, CodeRabbit uses adaptive limits for sustained high-volume activity. When a developer's recent PR review activity reaches the 95th percentile or higher among CodeRabbit users, additional reviews become available more gradually as earlier reviews age out of the rolling window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: ba5536d2-66fb-42cf-af83-af9a44bb72d5

📥 Commits

Reviewing files that changed from the base of the PR and between d8c6661 and 09f5e3c.

📒 Files selected for processing (1)

• python/packages/jumpstarter/jumpstarter/exporter/hooks_test.py

📝 Walkthrough

Walkthrough

read_pty_output now catches unexpected exceptions during PTY polling, logs them at debug level, and stops output reading. A macOS regression test verifies that hook execution still succeeds.

Changes

PTY output handling

Layer / File(s)	Summary
Reader exception handling python/packages/jumpstarter/jumpstarter/exporter/hooks.py, python/packages/jumpstarter/jumpstarter/exporter/hooks_test.py	The PTY reader logs unexpected exceptions and exits the loop. A macOS-targeted test verifies that a ValueError does not fail hook execution.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• jumpstarter-dev/jumpstarter#561: Both changes update read_pty_output exception handling.
• jumpstarter-dev/jumpstarter#826: Both changes modify PTY polling and add macOS coverage.
• jumpstarter-dev/jumpstarter#836: This change addresses the same macOS PTY race with broader exception handling.

Suggested reviewers: kirkbrauer, raballew

Poem

A rabbit reads the PTY stream,
A sudden error breaks the beam.
The error is logged,
The loop is unclogged,
And hooks complete as planned.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: catching unexpected exceptions in _flush_lines to prevent flaky failures.
Description check	✅ Passed	The description explains that unexpected exceptions are handled to prevent flaky CI hook failures.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ 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.}

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@python/packages/jumpstarter/jumpstarter/exporter/hooks_test.py`:
- Around line 1058-1066: Update the test around execute_before_lease_hook to
capture the mocked hooks.logger and assert the expected main-loop debug message
from the ValueError before asserting result is None. Ensure the assertion
distinguishes the main-loop handling from the finally drain, preserving coverage
of the main-loop exception path.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: ec1ca0b8-fa0a-4a55-991a-2d269861495c

📥 Commits

Reviewing files that changed from the base of the PR and between d17426e and d8c6661.

📒 Files selected for processing (1)

• python/packages/jumpstarter/jumpstarter/exporter/hooks_test.py