Re: [PATCH 0/2] Fix nss/tst-nss-files-hosts-long on single-stack hosts (bug 24816)

[Florian Weimer <fweimer@redhat.com>]

* Carlos O'Donell:

> On Tue, Sep 13, 2022 at 04:35:39PM +0200, Florian Weimer via Libc-alpha wrote:
>> Our Fedora builders started running the container tests (after the
>> switch to systemd-nspawn), and we encountered this test failure as well.
>> Fix this by disabling address configuration in the getent tool.
>
> Two things I'd like to discuss.
>
> (1) Change the getent default and drop AI_ADDRCONFIG.
>
> I'm hesitant to add a new option to getent as a solution to a testing
> problem. The documented description for getent ahosts talks only
> about enumerating the host entries or calling getaddrinfo with
> AF_UNSPEC. Could we just change the default and ignore the host
> configuration? This is less conservative but logically it seems to me
> that we could just drop AI_ADDRCONFIG, and add a --addrconfig option to
> get back the old behaviour. What could we possibly break?

I'm not sure why we would make such a backwards-incompatible change just
to fix a test.  It sounds even more preposterous than adding the new
option.

There have been support cases where the --no-addrconfig option would
have been useful.  Today, getent isn't a great tool for diagnosing DNS
issues, and I think this option improves the situation slightly.

> (2) Fix the test.
>
> Alternatively the test should be checking to see if it is in a dual
> stack environment or single stack environment and only call getent for
> the specific case when such interfaces are enabled.
>
> Can we resolve this entirely in tst-nss-files-hosts-long?

I think it's futile to try to replicate the AI_ADDRCONFIG behavior in
the test.

Thanks,
Florian