Re: Shall updaters fall back to other updaters?

["Ludovic Courtès" <ludo@gnu.org>]

Hi,

zimoun <zimon.toutoune@gmail.com> skribis:

> On Thu, 30 Jun 2022 at 10:58, Hartmut Goebel <h.goebel@crazy-compilers.com> wrote:
>
>> BTW 2: Which updater is used for each package is non-deterministic.
>
> From (guix discovery), ’all-modules’ is not deterministic because it
> depends on how the filesystem tree is walked.

Nope!  ‘all-modules’ *is* deterministic because it builds upon
‘scheme-files’, which is deterministic and documented as such.

> Maybe sorting ’%updaters’ would be enough; something like,
>
> (define %updaters
>   ;; The list of publically-known updaters.
>   (delay (sort (fold-module-public-variables (lambda (obj result)

Whether ‘fold-module-public-variables’ is deterministic depends on
whether ‘module-map’ is deterministic, which in turn depends on
‘hash-map->list’, which is not deterministic AFAICS.

So what we could do is replace uses of ‘module-map’ with a variant that
sorts variables.

That said, the only case where it can influence updater order is when
several of them are defined in the same module.

Thoughts?

Ludo’.