Re: ai_flags in calls to getaddrinfo, broader call for reproducibility check

[Robert Pluim]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Robert Pluim <rpluim@gmail.com>
>> Cc: Robin Tarsiger <rtt@dasyatidae.com>,  Eli Zaretskii <eliz@gnu.org>,
>>   emacs-devel@gnu.org
>> Date: Mon, 11 Jan 2021 21:12:44 +0100
>> 
>> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>> 
>> >> Because the select implementation on windows does a one-byte readahead
>> >> to see if data is available, which breaks UDP. I had a patch at one
>> >> point to fix this, but I remember Eli not being very enthusiastic
>> >> about it. Iʼve attached what I think is the right version below (my
>> >> windows box died, so I can't be sure)
>> >
>> > How 'bout installing it but make it conditional on some config var?
>> > And maybe set that config var if/when a UDP socket is requested?
>> 
>> I guess thatʼs possible. Iʼve now found the actual patch. If Eli
>> thinks itʼs worth persuing, I can make it conditional, unless someone
>> wants to spare me the trouble of setting up a working Windows dev
>> environment :-).
>
> My main concern is who will investigate the bug reports about this,
> debug the problem, find fixes, etc.?  If you or Stefan or someone else
> volunteers, then please go ahead.  But if you count on me, implicitly
> or otherwise, then let's wait for a volunteer to emerge.  Especially
> in this area, where I'm far from being an expert.  Don't forget that
> two threads are involved in this game, which provides ample
> opportunity for exciting deadlocks and races, apart of
> network-specific issues.

I donʼt think thereʼs too much scope for thread-induced breakage, but
this is threads, so that statement might well come back to bite me :-)

> (I'm sorry, but too often lately I'm the only one who gets to debug
> and fix MS-Windows specific issues; if I don't do that, the build
> remains broken for days.  It's too much of a burden on me, and takes a
> significant enough fraction of my time that I must be very cautious
> with adventures.  Otherwise, I won't be able to do my main job here,
> which I already am barely capable of doing.)

I can understand this. I donʼt run windows except in a VM, and the
whole reason for the patch initially was to reduce the differences in
the network implementation between different platforms (you can call
this an obsessive desire for parity on my part if you like).

If the cost of making udp processes work on Windows is not worth it,
then we can stop here.

Robert