Re: "guix system reconfigure" downloads 2G of stuff it doesn't need

[Zack Weinberg]

On Tue, Jul 30, 2024, at 10:43 AM, Leo Famulari wrote:
> On Mon, Jul 29, 2024 at 10:31:35AM -0400, Zack Weinberg wrote:
>> Why does it need to download all of this stuff that I know it doesn't
>> actually need (given that "guix gc" deleted it)?  In particular it
>> appears to be downloading build dependencies for everything whether
>> or not it is going to use a substitute for them, and also packages
>> that I have intentionally excluded from the system configuration.
>
> Very generally, these programs are considered necessary to build the
> system generation itself.
>
> I'm not claiming that each of these programs is executed in the
> process of building the generation, but they are considered by Guix
> to be required, either directly or transitively, in order to perform
> this work.

Is there a good way to investigate _why_ each of these packages is
considered necessary to build the system generation, and, equally
importantly, why they are _not_ considered necessary by "guix gc"?

zw