Print threads backtrace on SIGINFO/SIGPWR

[sobrinho]

Description

Debugging stuck builds is always tricky and this will add a thread backtrace dump to STDERR when the process is signaled with SIGINFO (macOS) or SIGPWR (linux).

On macOS you can use CTRL+T to signal the running process. Linux you can use kill -PWR pid.

I have a PR open against RSpec as well here.

This is a common pattern used by Sidekiq and Puma that I'm aware of but possibly other projects as well.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds new behaviour)

Please add an entry to the relevant section of CHANGELOG.md as part of this pull request.

Checklist:

Your PR is ready for review once the following checklist is
complete. You can also add some checks if you want to.

• Tests have been added for any changes to behaviour of the code
• New and existing tests are passing locally and on CI
• bundle exec rubocop reports no offenses
• RDoc comments have been updated
• CHANGELOG.md has been updated

[luke-hill]

Ignore any failing tests in CI for the CCK

[luke-hill]

This has CI failures related to this code. I'm currently knee-deep in investigating / fixing up other areas of the main codebase so won't be able to dive into this much in the next 1-2 weeks

[sobrinho]

@luke-hill fixed

[sobrinho]

Failures are not related to this PR.

[sobrinho]

@luke-hill would you fire the workflows again? Updated with main.

[luke-hill]

The failures are on main, so for now I just want to focus on getting main fixed up. I know what final bits need fixing. So for now this looks good.

Just give me a small amount of time to get back to you on this.

[luke-hill]

Hi @sobrinho

All of the existing issues I needed to fix are now done. I've asked copilot to give this a quick review.
Can you rebase / merge with main at which point CI should be fully green.

Once that's all done I'll give it one last review and endeavour to merge this and release v11

[Copilot]

Pull request overview

Adds a signal handler to the Cucumber CLI to dump all threads’ backtraces to the error stream when receiving SIGINFO (macOS) or SIGPWR (Linux), to help debug stuck builds.

Changes:

• Register a SIGINFO/SIGPWR trap during Cucumber::Cli::Main#execute! to print a per-thread backtrace dump to @err.
• Add a CLI spec that triggers the signal and asserts a backtrace line is emitted.
• Document the new behavior in CHANGELOG.md.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
lib/cucumber/cli/main.rb	Adds trap_thread_dump_signal and hooks it into execute! to print thread backtraces on SIGINFO/SIGPWR.
spec/cucumber/cli/main_spec.rb	Adds a spec that sends SIGINFO/SIGPWR to self and verifies a backtrace dump is written to stderr.
CHANGELOG.md	Adds an “Unreleased” changelog entry for the new thread-dump-on-signal behavior.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[luke-hill]

@sobrinho if you're able to get this fixed up reviews wise and CI wise in the next few days I can commit to merge this and deploying this into v11. WDYT?

[sobrinho]

@luke-hill fixed!