bug#27476: guix pull fails on powerful server

[Andy Wingo <wingo@igalia.com>]

On Fri 22 Sep 2017 16:10, ludo@gnu.org (Ludovic Courtès) writes:

> Hi Ricardo,
>
> Ricardo Wurmus <rekado@elephly.net> skribis:
>
>> The following derivation will be built:
>>    /gnu/store/yvyfkns3w3vm7ynwbr7mvxcmin4gd2a0-guix-latest.drv
>> copying and compiling to '/gnu/store/7m52dkr98nhwgpsx20mmpwyw2yzj58d3-guix-latest' with Guile 2.2.2...
>> loading...       25.4% of 629 filesrandom seed for tests: 1506066913
>> loading...       99.8% of 629 files
>> compiling...     69.2% of 629 filesice-9/threads.scm:289:22: In procedure loop:
>> ice-9/threads.scm:289:22: Syntax error:
>> guix/scripts.scm:130:2: >>=: >>= (bind) used outside of 'with-monad' in form (>>= (apply set-build-options* #:use-substitutes
>> ptions)) (lambda (unused-value) (mbegin %store-monad (mlet %store-monad ((derivation (origin->derivation (package-source pack
>> tutes? use-substitutes? #:dry-run? dry-run?) (return (show-derivation-outputs derivation)))))))
>
> This was reported at <https://bugs.gnu.org/27476>, and I suspect a
> thread-safety issue.  However, syntax parameters are purely functional
> AFAICS, so I fail to see why multithreading could be a problem.
>
> Andy, any idea what could be causing this?

I have heard of but not seen a number of similar bugs: errors that
"can't happen" but which appear under multiple threads.  I don't know
what underlying pattern is.  Has anyone found a test case that reliably
reproduces?

Andy