bug#47115: Failure building grub-img.png when reconfiguring

[Jack Hill]

On Sat, 13 Mar 2021, Mark H Weaver wrote:

> Thanks.  Given this, and the lack of similar reports from others, my
> guess is that you hit a non-deterministic Guile bug, possibly the same
> one as <https://bugs.gnu.org/46879> (Non-deterministic failures while
> building Guix with Guile 3.0.5).
>
> If the problem happens reproducibly on that one VM only, that suggests
> that the bug might have led to a corrupted store item, i.e. a store item
> containing a .go file with bad code.  If so, running "guix gc" might be
> sufficient to clear the corrupted items.

guix gc and the reconfigure again (now with 
373c7b5791acd8f377455be47260948b843dd5db) still results in the same error. 
Of course, if the miscompilation was in something that couldn't get 
collected… However, I have been able to reproduce it on that one VM across 
multiple Guix commits.

Best,
Jack