bug#19671: Raw binary data in build log from substitute-binary

[ludo@gnu.org (Ludovic Courtès)]

Mark H Weaver <mhw@netris.org> skribis:

> Mark H Weaver <mhw@netris.org> writes:
>
>> While trying to install 'racket' using substitutes, several lines of the
>> form "substitute-binary: <binary garbage>" were output.  See the
>> attachment for the precise output, captured via Emacs' shell mode.
>>
>> This was when running guix from git commit 2dfed64 on an i686 GSD
>> system.
>
> The same problem happened to me again, this time on git commit 710f3ce,
> while running 'guix system build'.  I've attached another transcript.
>
> The binary junk is immediately followed (with no intervening newline) by
> the message:
>
> http://hydra.gnu.org/2zadn0b2kljwlsyarr3j5rz44yi2pvs3.narinfo' failed: 502, "Bad Gateway"
>
> This suggests that nginx had a problem fetching it from hydra-server on
> port 3000.  Repeating the same command worked properly.

I don’t see how the binary garbage could reach the stdout of ‘guix
substitute-binary’.  This happens when hydra.gnu.org is overloaded as
you suggest, so perhaps we have a connection closed unexpected or
something like that, but still.

Since this is the multithreaded ‘substitute-binary’, could there be
something fishy going on in wrt. threads?

Ludo’.