[bug#29928] [PATCH 0/5] Optimize profile hooks

[iyzsong@member.fsf.org (宋文武)]

ludo@gnu.org (Ludovic Courtès) writes:

> Hello!
>
> 宋文武 <iyzsong@member.fsf.org> skribis:
>
>> Hello, these patches make each profile hook run upon its specified interested
>> inputs, eg: the 'info-dir-file' hook only get inputs with info manuals,
>> install a package without info files won't trigger it.  Thus reduce the chance
>> and time to rerun them when your profile changed.
>
> That’s an area in need of improvements, thanks for looking into it!
>
>> One drawback is 'guix package --dry-run' no longer report the derivations of
>> profile hooks, and the derivation of profile it reports is not the real one.
>> Addition files will be built when the profiles hooks are run.
>
> FWIW I’m not entirely convinced by the approach.

Well.. these patches modify package hooks to:

1. build all manifest inputs first.

2. filter manifest inputs to get interested ones.

3. run hook with its interested inputs.

I think reducing the inputs of hook from the whole manifest to its
interested ones is the only way to avoid unneeded reruns.


> As discussed earlier, I’d like to experiment with a notion of “build
> rounds”: the first round would build a profile without any hooks, the
> second round would, depending on what the profile contains, rebuild it
> with certain hooks.

I think "build rounds" would improve the UI/UX, and by changing inputs
from manifest inputs to a built profile, it would simply the current
implementations of profile hooks, but it won't avoid unneeded reruns
compare to the filtered interested inputs way.

Is my understanding correct?