A few applications such as gnome-music load the GIRepository typelib
and use it to adjust their search paths.
GLib 2.79.x now provides libgirepository-2.0.so.0 (GIRepository-3.0),
but each OS distribution is likely to have a transitional period during
which GLib's libgirepository-2.0.so.0 has become available, but bindings
like PyGI and gjs are still linked to gobject-introspection's
libgirepository-1.0.so.1 (GIRepository-2.0).
During this transitional period, interpreted languages that load the
GIRepository namespace could get the "wrong" version, which will result
in adjusting a search path that will not actually affect the language
binding's typelib lookup, and could also lead to symbol and type-system
conflicts.
We can avoid this collision by making GLib's GIRepository library refuse
to load versions of the GIRepository typelib that are not 3.0, and
similarly making gobject-introspection's GIRepository library refuse to
load typelib versions that are not 2.0. A relatively neat way to achieve
that is to make each version behave as if the other one doesn't exist.
Signed-off-by: Simon McVittie <smcv@debian.org>
e6c8c75ccc