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

[Eli Zaretskii <eliz@gnu.org>]

> From: Robin Tarsiger <rtt@dasyatidae.com>
> Cc: emacs-devel@gnu.org
> Date: Mon, 11 Jan 2021 04:47:11 -0600
> 
> > Note the difference in he.net resolution with and without the 'ipv6
> > argument, and also the behavior of ipv6.google.com with the ipv6
> > argument.  Interesting, no?
> 
> Definitely. The behavior of "he.net" with 'ipv6 in the former group
> is something I think of as to be avoided, per elsethread, but this
> shows the latter truncation for nil more concretely, of course...
> and the error-swapping behavior with "ipv6.google.com" is bizarre
> and hard to reconcile with earlier observations, especially the
> nil-family case. I wonder whether that changes with 'ipv4?

No, it behaves as expected.

> Your ipconfig result showed no "real" IPv6 connectivity

How did you see this?  Would it be possible to deduce that from the
output of, say, network-interface-list?

I'm asking because I'm still bothered by failures in those two tests,
and would like to avoid that.  I think it's bad if a test fails when
there's nothing wrong with Emacs; we should try to skip such tests
when we know their results cannot be trusted.

Thanks.