zimoun schreef op do 03-02-2022 om 03:19 [+0100]:
> The issue is because concurrency.  If two time-machines are run
> concurrently, they both update ~/.cache/guix/checkouts/ and the end
> result is hard to predict.
> 
> Well, I probably ran inside one terminal “guix time-machine
> --commit=XXXX -- help” where XXXX a commit with openblas@0.3.9; and in
> the same time inside another terminal, “guix time-machine
> --commit=4b1538e6ef -- help”.  Depending on “the same time”, the state
> of the checkout
> ~/.cache/guix/checkouts/pjmkglp4t7znuugeurpurzikxq3tnlaywmisyr27shj7apsnalwq
> used by the time-machine at 4b1538e6ef was the state for the commit
> XXXX.
> 
> Then, all is messed!

FWIW it's a known issue but I can't find it on issues.guix.gnu.org.
The (unimplemented) fix is to use worktrees, or don't checkout and use
the libgit2 / (guix git) equivalent of
"git show 46fc72b2bfee2a30a3c3f3320e7d84b4b2fd646e some-file".

Greetings,
Maxime