The files in dnf5/dnf5daemon-server/dbus/interfaces/*.xml do not match reality, at least the signals are wrong with what is sent to the client: 11:59:35:690 GLib-GIO Dropping signal transaction_verify_start of type (st) since the type from the expected interface is (t) 11:59:35:690 GLib-GIO Dropping signal transaction_verify_progress of type (stt) since the type from the expected interface is (tt) 11:59:35:694 GLib-GIO Dropping signal transaction_verify_progress of type (stt) since the type from the expected interface is (tt) 11:59:35:695 GLib-GIO Dropping signal transaction_verify_stop of type (st) since the type from the expected interface is (t) 11:59:36:205 GLib-GIO Dropping signal transaction_action_start of type (ssit) since the type from the expected interface is (sut) 11:59:36:205 GLib-GIO Dropping signal transaction_action_progress of type (sstt) since the type from the expected interface is (stt) 11:59:36:241 GLib-GIO Dropping signal transaction_action_stop of type (sst) since the type from the expected interface is (st) 11:59:39:169 GLib-GIO Dropping signal transaction_script_start of type (ssi) since the type from the expected interface is (s) 11:59:39:362 GLib-GIO Dropping signal transaction_script_stop of type (ssit) since the type from the expected interface is (st) You also send a lot more signals (for example the one for package download is missing in the .xml file), I noticed that with a dbus-monitor, but as I asked for an overall progress in bug #2124994 it can be dealt with there.
I forgot to mention, I'm at commit 1cfdcf554bd73ffa635915079f06bcee0b8c193e of the `dnf5` project.
This bug appears to have been reported against 'rawhide' during the Fedora Linux 38 development cycle. Changing version to 38.
Trying with 5.1.0 it seems the .xml files had been updated (or the code under the hood), because I do not see any such runtime warning any more, thus I'm closing this for now.