bug#64187: guix locate: unsupported manifest format

[Ricardo Wurmus]

I ran “guix locate” on the HPC cluster where we generally don’t ever run
“guix gc”.  Here’s what I got:

--8<---------------cut here---------------start------------->8---
$ time guix locate ls
guix locate: indexing files from /gnu/store...
guix locate: traversing local profile manifests...
guix locate: error: unsupported manifest format

real    2m24.029s
user    3m11.519s
sys     0m5.617s
--8<---------------cut here---------------end--------------->8---

It would be good if it printed the location of the problematic manifest
and ignored it.

-- 
Ricardo