Run the cleanup routines even if the main goroutine panics

[richvdh]

We should stop any running containers on panic, and things like complement-crypto expect their cleanup handlers to be run.

There is a comment in complement-crypto to this effect (https://github.com/matrix-org/complement-crypto/blob/6ba55b6fb878dd44872edc44d9632241d253a8cc/internal/cc/instance.go#L42), and that expectation seems to have been broken by the transition to WithCleanup.

[MadLittleMods]

Would this also work? (less layers)

Suggested change

	// Run the cleanup functions even on panic.
	runAndCleanup := func() int {
	defer testPackage.Cleanup()
	if opts.cleanup != nil {
	defer opts.cleanup(testPackage.Config)
	}
	return m.Run()
	}
	testPackage.Cleanup()
	os.Exit(exitCode)
	os.Exit(runAndCleanup())
	defer testPackage.Cleanup()
	if opts.cleanup != nil {
	defer opts.cleanup(testPackage.Config)
	}
	exitCode := m.Run()
	os.Exit(exitCode)

[richvdh]

I don't think so. Per https://pkg.go.dev/os#Exit, deferred functions are not run on os.Exit. The extra layer gives the deferred functions a chance to run.

I'll add a comment to clarify this.