Re: signal handling different in 1.8.3 than 1.8.1?

[Ludovic Courtès]

Hello,

Gregory Marton <address@hidden> writes:

>> The following message is a courtesy copy of an article
>> that has been posted to gmane.lisp.guile.bugs as well.
>
> Is address@hidden now out of date?   I may have to get a
> newsreader. Are they mirrored?

No, address@hidden' is not outdated: it's just that I'm posting
through Gmane (http://gmane.org/), which is a mail/news bi-directional
gateway.  The above notice is issued (I think) by Gmane someone is
explicitly Cc'd to a newsgroup post.

> Nevertheless, it has consistently passed in 1.8.1 and consistently
> fails in 1.8.3 with no other changes.

Sure, but a quick glance at `NEWS' didn't reveal anything obviously
related to the problem at hand.

BTW, you might want to even switch to 1.8.5 while you're at it.

> call-with-unblocked-asyncs complains:
>     misc-error: asyncs already unblocked

OK, so it's not needed.

> With (sleep 0) is no different than without.

I just tried and it depends on where you place it.  For instance, a
`format' call (which also does `SCM_TICK' as a side effect) within the
second lambda passed to `ensure' in `with-sigaction' does the trick.

The key insight here is that signal delivery in Guile is asynchronous,
so you can't know for sure when it will happen.  It'd be nice to be able
to force system asyncs to run, though.

As to why there's such a reproducible difference between 1.8.1 and
1.8.3, maybe you could try using `git-bisect' to find out which change
set between tags `release_1-8-1' and `release_1-8-3' introduced the
change in behavior.  I think it's probably a side-effect of some
unrelated change but again, a valid side-effect.

Hope this helps,
Ludovic.