Re: How to deal with system-wide state databases

[Roel Janssen]

Ludovic Courtès writes:

> Roel Janssen <address@hidden> skribis:
>
>> Ludovic Courtès writes:
>>
>>> Hello!
>>>
>>> Roel Janssen <address@hidden> skribis:
>>>
>>>> How should we deal with mechanisms like this?  Should I change the 
>>>> scrollkeeper
>>>> database directory per program, so in this case it becomes:
>>>> /gnu/store/xgbvyqs...-gparted-0.26.0/var/lib/scrollkeeper
>>>>
>>>> Or can we deal with this in a more cross-package way?
>>>
>>> Maybe we could add a profile hook to ‘%default-profile-hooks’ in (guix
>>> profiles)?
>>
>> I think people only need Scrollkeeper when they wish to have the
>> documentation available in Yelp (GNOME's help browser).  So it only
>> affects a few people I believe.
>
> I think documentation is quite useful, in general.  :-)
>
>> Would it then still make sense?  Maybe this hook should only be active
>> when Yelp is installed in the profile on which the transaction
>> operates.  Is that possible?
>
> Definitely.  For instance, ‘ghc-package-cache-file’ does exactly this
> kind of trick.  (It’s not completely satisfying, since we’re simply
> matching file names, but it does the job.)

When I looked into the code and what derivations are actually built in
my profile I noticed 'ghc-package-cache-file' was not among them.  So,
this is actually what I need. :-)

>> With this construct, I'd have to patch out the 'scrollkeeper-update'
>> command from the GParted build system.
>
> Yes.

Great.  So the next step with GParted is to create a
'scrollkeeper-database' hook.  I'm not sure how to do that by looking at
the existing hooks, but I will attempt to create one.

Thanks!

Kind regards,
Roel Janssen