Root cause found, and it is not the same as the Anaconda issue in https://gitlab.gnome.org/GNOME/pygobject/-/work_items/764 - cinnamon-screensaver exports its D-Bus interface through the C skeleton generated by gdbus-codegen, so it never goes through the Python register_object() override.
What breaks it is that GLib.Pid is no longer an int. Up to 3.56.3 it was gi._gi.Pid, a C type deriving from int; since 3.57.0 (upstream commit b6e14902, "Reimplement GLib.spawn_async in Python") it is: class Pid: def __init__(self, pid): self._pid = pid def __int__(self): return self._pid def close(self): GLib.spawn_close_pid(self._pid) No __index__, no rich comparisons. So for any application that keeps the result of GLib.spawn_async() around, `pid > 0` now raises TypeError and os.kill(pid, sig) no longer works. In cinnamon-screensaver this aborts the unlock path and leaves the screen locked (details in #1143872). I have patches for cinnamon-screensaver ready and also posted upstream, so this should not hold pygobject back for long. But I would suggest raising it with pygobject upstream as well: it is a silent API break with no NEWS entry and no porting note, the class is unchanged in git main, and any other Python application using GLib.spawn_async() is exposed to it. Adding __index__ and the integer comparisons back (or simply deriving from int again) would keep the old code working.
OpenPGP_signature.asc
Description: OpenPGP digital signature
