Re: "desktop-base" for wheezy+1

[Ulrich Hansen <uhansen@debianart.org>]

Am 12.07.2012 um 01:15 schrieb Paul Tagliamonte:
>> IMHO it's a good idea to use common alternatives. In our experimental theme package, gdm3, kdm, grub-theme, plymouth and the gnome-lockscreen use the same picture, provided by the alternative "desktop-login". So, in the wheezy+1 vision, which package would be in charge of that alternative?
>> 
> 
> alternatives can be added by many packages, just btw

But all of these many packages would have to agree on which alternatives they all want to use together. So there is communication needed.

> Joe-bob works for Foocorp, which uses "nihde" as their DE. "nihde" can
> run apps as "widgits", and the theme they wrote for their installs
> happens to have a theme that uses "xblerg". The theme is so brilliant
> they want to share it with all Debian users, so they upload it.
> 
> Now, the situation:
> 
> Does theme-foocorp depend on xblerg? Remember, by default Debian doesn't
> use nihde, so we don't need it for most cases. If we assure xblerg
> (which happens to be 1.4 gigs of glorious userspace) is on the system in
> the one big megapackage, it screws a lot of installs with a huge useless
> app. If we don't it causes breakage.
> 
> With my solution, the answer is clear. As is, there is no good answer.

You are talking about depends. But IMHO desktop-base does a good job to keep depends small. For instance plymouth: Although desktop-base installs a plymouth theme, it doesn't depend on plymouth or plymouth-drm.
Instead postinst just checks for it:

update_plymouth_config() {
    if which plymouth-set-default-theme > /dev/null ; then
        plymouth-set-default-theme growing || true
    fi
}

So desktop-base activates the theme only of it finds a working copy of plymouth.

So nothing is screwed, there are no huge useless apps installed. 

> The idea here is to prevent the theoretical problem embodied in bugs
> 613040, 625222 and 680583.

The user of 613040 has just a broken install of plymouth. He can reinstall plymouth and plymouth-drm and he is free to go. The procedure how to get plymouth to work is described excellently at http://wiki.debian.org/plymouth. The idea to make desktop-base recommend plymouth because of this is absurd. The plymouth theme in desktop-base works for everybody who has plymouth working correctly on his or her system. It doesn't change anything for the others. Why not keep it that way?

625222 seems to be solved because postinst now checks if the command /usr/sbin/plymouth-set-default-theme is working (see above).

The depend mentioned in 680583 is caused by the fact that some people find it more elegant to include wallpaper pictures as svg instead of png. The pictures have to be rendered by the system to be bitmaps again in the end. This works for gnome but not for KDE. So desktop-base includes svgs for gnome and a depend on the renderer (librsvg2-common). For KDE it includes the same graphics as png. 

So to get rid of the depend (and make things easier), why not just return to png? Or (if you don't like that) make it possible that png is used instead of svg if  librsvg2-common is not installed? Wouldn't this be possible with the alternatives in postinst and if.. then?

regards