[Pkg-rust-maintainers] Bug#842634: Bug#842634: rustc: FTBFS (sys_common::net::tests::no_lookup_host_duplicates fails)

[Santiago Vila]

On Tue, 29 Nov 2016, Ralph Giles wrote:

> On 2016-11-29 1:17 AM, Santiago Vila wrote:
> 
> > I wonder, however, why two lines like this in /etc/hosts
> > 
> > 127.0.0.1       localhost
> > 127.0.0.1       localhost ip6-localhost ip6-loopback
> > 
> > should make rustc build to fail at all.
> 
> The test was added in https://github.com/rust-lang/rust/pull/34700 to
> guard against regression of a bug where std::net::lookup_host()
> incorrectly returned multiple copies of each address.
> 
> The /etc/hosts database format certainly allows duplicate entries. It
> seems that glibc, at least, does not merge those, but instead returns
> the listed n-to-m mappings directly through the `struct hostent`
> returned by both gethostbyaddr() and gethostbyname().
> 
> Even if it doesn't violate any spec, I agree with Luca that this is a
> misconfiguration. The normal application of multiple address entries
> is for service failover. Any client connecting to localhost with your
> configuration will immediately retry connection failures, which is a
> waste of resources. [...]

Ok, but the duplicate localhost entry, as I explained, is not
something which I deliberately chose, it's the result of using
schroot on a machine not having IPv6 enabled.

Unless IPv6 has become mandatory for autobuilders (I hope not),
this is still a bug (i.e. definitely *not* wishlist) in schroot,
for converting ::1 into 127.0.0.1 and causing the FTBFS problem.

I'll reassign it.

Thanks.