bug#40998: [PATCH 1/4] system: Add a version field to the <boot-parameters> record.

["Ludovic Courtès" <ludo@gnu.org>]

Hi!

Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:

> This version field exposes the (already present) version information of a boot
> parameters file.
>
> * gnu/system.scm (%boot-parameters-version): New variable.
> (<boot-parameters>)[version]: New field.
> (read-boot-parameters): Use it.
> (operating-system-boot-parameters-file): Likewise.
> * tests/boot-parameters.scm (test-read-boot-parameters): Use
> %boot-parameters-version as the default version value in the template.

[...]

> +  ;; New versions are not backward-compatible, so only accept past and current
> +  ;; versions, not future ones.
> +  (define (version? n)
> +    (member n (iota (1+ %boot-parameters-version))))
> +
>    (match (read port)
> -    (('boot-parameters ('version 0)
> +    (('boot-parameters ('version (? version? version))

I still have a preference for an explicit list right here, for clarity,
and so that we don’t unwillingly find ourselves treating any past
version in the same way in the future.

I think I wasn’t clear about it (sorry!) but I wonder if we could,
instead of bumping the version, use something like:

  (find (cut string-prefix? "gnu.load=") kernel-arguments)

to determine whether we’re dealing with an “old-style” “parameters”
file.

If that’s not possible, then what this patch is doing SGTM.

Thanks,
Ludo’.