Bug#1118613: transition: pygobject 3.54

[Simon McVittie]

Package: release.debian.org
Severity: normal
X-Debbugs-Cc: pygobject at packages.debian.org
Control: affects -1 + src:pygobject
User: release.debian.org at packages.debian.org
Usertags: transition

pygobject >= 3.52 has switched from libgirepository-1.0 to
libgirepository-2.0 as its way to access GObject libraries such as GTK, 
resulting in a transition being needed. I think we're ready for this 
now, and I think it can happen either before or after GNOME 49 (which is 
blocked by #1116563).

libgirepository-1.0 and libgirepository-2.0 can be installed on the same 
system, but they cannot both be used within the same process, because 
they both register a GObject type named "GIRepository". This means that 
pygobject, libpeas, and some apps all need to agree on which version 
they are going to use (and unfortunately versioned symbols would not 
help here either).

This will need a coordinated upload of these GNOME team packages, all of 
which have versions in experimental that can be re-uploaded to unstable:

* pygobject (#1099164)
* libpeas (#1118363), but not libpeas2
* eog (no bug)
* gedit (no bug)
* rhythmbox (no bug)
* totem (no bug)

These non-GNOME packages have patches available and will need either 
uploading to unstable or removing from testing:

* entangle (#1118501)
* eom (#1118496)
* liferea (#1118500)
* pluma (#1118497)

I expect that the autoradio package will also regress with the new 
pygobject (#1118278) because it uses the pygtkcompat compatibility layer 
for migrating from pygobject 2 to 3, which was finally removed in 3.54. 
I don't have a patch for this.

In the next upload of the new pygobject I intend to add versioned Breaks 
on the known-broken packages, with the assumption that their next upload 
will fix the incompatibility, unless the release team would prefer not 
to have those Breaks.

Finally, glib2.0 (>= 2.86.0-7) will need to migrate first, to avoid 
regressions in packages like ibus-anthy and isenkram that need typelibs 
from the legacy non-multiarch directory. The next upload of the new 
pygobject will add a versioned dependency to make sure that the fixed 
glib2.0 is ready first, and it should migrate in a few days anyway.

These packages depend on both python3-gi and either 
libgirepository-1.0-1 or gir1.2-girepository-2.0, but don't appear to 
need any changes:

* blueprint-compiler
* cinnamon
* endeavour
* exaile
* gnome-builder
* gnome-music
* gtk-meshtastic-client
* pympress
* rednotebook

Thanks,
    smcv