bug#20217: Allow users to use the daemon's default settings

[ludo@gnu.org (Ludovic Courtès)]

ludo@gnu.org (Ludovic Courtès) skribis:

> Mark H Weaver <mhw@netris.org> skribis:
>
>> Ludovic Courtès <ludo@gnu.org> writes:
>>
>>> commit 4d58122071bbd7bb56c9658a9bbe7621bf3e423d
>>> Author: Ludovic Courtès <ludo@gnu.org>
>>> Date:   Sun Mar 22 23:43:25 2015 +0100
>>>
>>>     store: Default to a non-empty list of substituters.
>>>     
>>>     Fixes <http://bugs.gnu.org/20163>.
>>>     Reported by Mark H Weaver <mhw@netris.org>.
>>>     
>>>     * guix/store.scm (%default-substitute-urls): New variable.
>>>       (set-build-options): Change default value of #:substitute-urls to
>>>       %DEFAULT-SUBSTITUTE-URLS.
>
> [...]
>
>> Does this mean that even if I've configured my daemon to use a different
>> set of substitute-urls, when I run 'guix' as root those settings will be
>> overridden?
>
> Yes.

This particular issue of substitute URLs is fixed in fb4bf72.

The more general problem remains though: for all the other options, like
max-build-jobs, timeout, etc., the client settings take precedence over
the daemon settings because the ‘set-build-options’ RPC doesn’t provide
a way to say “use default value.”

The fix for that will be either: (1) a ‘set-build-options2’ RPC that has
a way to leave some settings unchanged, or (2) a ‘get-build-options’ RPC.

Option (1) is simpler and more efficient, but option (2) could be
interesting.

Ludo’.