Re: Shall updaters fall back to other updaters?

[Kaelyn]

------- Original Message -------
On Sunday, July 3rd, 2022 at 1:12 AM, Hartmut Goebel 
<h.goebel@crazy-compilers.com> wrote:


> Am 01.07.22 um 15:15 schrieb Ludovic Courtès:
>
> > > BTW 2: Which updater is used for each package is non-deterministic.
> > > Do you have an example? I’d think they’re always tried in the same
> > > order, no?
>
>
> When looking at the code, I don't see any means of sorting:
> https://git.savannah.gnu.org/cgit/guix.git/tree/guix/upstream.scm#n245
>
> and below. (Maybe sorting is hidden in one of the function
> guile-internal used there there.)

I just looked at 'importer-modules and did some tracing of where the list of 
modules come from (back through 'all-modules, etc). It appears that by default 
the list of importer modules comes from 'scheme-file, which is defined at:

https://git.savannah.gnu.org/cgit/guix.git/tree/guix/discovery.scm#n43

That function builds a list of scheme files found recursively under a given 
directory with the help of 'scandir*. There is no sorting there or along the 
call chain back to 'importer-modules, so I'm fairly sure the directory entries 
are returned in a filesystem-dependent order. If the filesystem returns entries 
in sorted order or if the contents of that directory tree are relatively static 
(in that the order of directory entries hasn't changed), then the results will 
appear to be in a consistent/deterministic order. To me, this feels like the 
importers will need a more deterministic order imposed on them to get import 
results that are consistent across systems. HTH!

Cheers,
Kaelyn