Re: Shall updaters fall back to other updaters?

[zimoun]

Hi,

On mer., 06 juil. 2022 at 16:16, Ludovic Courtès <ludo@gnu.org> wrote:

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

Oh indeed!  My bad, I have overlooked that ’scheme-files’ uses
’scandir*’ instead of Guile scandir; and this scandir* defined in (guix
syscall) sorts the result.


>> 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.

Indeed, and that’s the case, no?  From [1]:

        bioconductor cran 
        savannah generic-html gnu-ftp sourceforge xorg kernel.org gnu

        cran bioconductor
        kernel.org sourceforge gnu generic-html gnu-ftp xorg savannah
       
        bioconductor cran
        sourceforge generic-html gnu-ftp savannah xorg kernel.org gnu

we see that the updaters are file-sorted (removed here) and only they
appear unsorted when defined in the same module (underlined here).


Well, I count 5 calls to ’module-map’.  Do you mean replace all of them
by ’module-map*’ which guarantees a stable order?  Or only ’module-map’
defined in ’fold-module-public-variables’ and
’fold-module-public-variables*’?


1: 
<9a68beb7-50f0-9998-9daf-2b036a8e9e66@crazy-compilers.com">https://yhetil.org/guix/9a68beb7-50f0-9998-9daf-2b036a8e9e66@crazy-compilers.com>


Cheers,
simon