Re: "no duplicate" in `popen.test'

[ludo@gnu.org (Ludovic Courtès)]

Hi Neil,

Neil Jerram <neil@ossau.uklinux.net> writes:

> ludo@gnu.org (Ludovic Courtès) writes:
>
>> Hello,
>>
>> That "no duplicate" test in `popen.test' leaves a zombie behind it [0].
>> The fix would be to `waitpid' the process created by `open-input-pipe'
>> (see attached patch), but that makes it hang, waiting for "sleep 999" to
>> complete.
>
> I've attached an alternative possible solution, using feedback from
> the parent to the child to avoid needing the long sleep.

Good idea.

It apparently fixes the problem.  I think we also need that change in
the second "no duplicate" test, don't we?

> Unfortunately, though, I didn't manage to observe the zombie process
> with the test as it was before.  (How do I do this on GNU/Linux?)  So
> I don't really know whether this is a significant improvement.

You can just run "./check-guile && pstree -u $USER".  That shows whether
there are any processes left (whether zombie or not).  "ps" can then
tell whether these are zombies, when marked with a `Z'.

>> I'm not sure whether it's an indication that the bug was caught, or
>> rather an indication that the test is broken, especially since I don't
>> fully understand the bug that it's trying to catch.
>
> If waitpid fixes it, doesn't that point to the test being broken?

Hmm, I don't know, why?

Thanks,
Ludovic.