Zhu Zihao schreef op za 12-03-2022 om 10:38 [+0800]:
> > What if a program uses both 'pango' and gtk?  Then IIUC, it would
> > simultanuously use pango and pango-next in the same process, which
> can
> > easily cause problems (see e.g. the bug report about segfaults
> > involving multiple libcairos).
> 
> If package A propagates C@1.0 and package B propagates C@2.0. Guix
> will
> raise an error. However, it doesn't care about something like
> 
> guix shell gtk pango@1.48
> 
> IDK which pango will win the game.

'guix install' and 'guix shell' might not care, but how would this stop
the segfaults caused by multiple versions of the same library in the
same process?

Also, gtk currently propagates pango@1.48.0, the same pango as
pango@1.48, so this doesn't seem a good test to me.

Instead:

$ guix shell gtk pango@1.42.4

Looks like $GUIX_ENVIRONMENT/share/doc/ only contains pango-1.42.4 and
not pango-1.48.  Looks like a bug?

Next I tried:

$ guix shell pango@1.42.4 pango@1.48

this also does not complain and the share/doc only contains pango@42.4.
Also looks buggy?  I'll send a bug report.

> 
> I've asked in https://debbugs.gnu.org/cgi/bugreport.cgi?bug=44327 and
> suggest to introduce priority mechanism like Nix. But Ludovic Courtès
> doesn't accept my suggestion

How could a priority mechanism solve the segfaults?

Greetings,
Maxime.