Bug#956870: gnome-shell: Incompatible versions in testing

[Simon McVittie]

On Thu, 16 Apr 2020 at 09:05:55 +0200, Marc Glisse wrote:
> Apr 16 08:18:30 stedding gnome-shell[5986]: cannot register existing type 'GnomeBGSlideShow'
> Apr 16 08:18:30 stedding gnome-shell[5986]: cannot add private field to invalid (non-instantiatable) type '<invalid>'
> Apr 16 08:18:30 stedding gnome-shell[5986]: **
> Apr 16 08:18:30 stedding gnome-shell[5986]: GnomeDesktop:ERROR:../libgnome-desktop/gnome-bg-slide-show.c:86:gnome_bg_slide_show_set_property: assertion failed: (GNOME_BG_IS_SLIDE_SHOW (object))
> Apr 16 08:18:30 stedding gnome-shell[5986]: Bail out! GnomeDesktop:ERROR:../libgnome-desktop/gnome-bg-slide-show.c:86:gnome_bg_slide_show_set_property: assertion failed: (GNOME_BG_IS_SLIDE_SHOW (object))

This is caused by the binNMUs for the gnome-desktop3 transition being
incomplete. GNOME Shell ends up loading two different versions, and they're
incompatible.

This is not something that can easily be solved by the package's
maintainers. The solution is to add versioned Breaks, but
package rebuilds happen in unstable, so we can't get a rebuilt version
into testing until the new gnome-shell migrates.

> so it would
> be nice either to downgrade the packages that just migrated to testing,
> or to boost the migration of gnome-shell to testing

This is not something that the maintainers can do unilaterally. We have
to rely on the release team to get the new version migrated.

    smcv