gnome-shell runs out of dbus match rules on the system bus
gnome-shell seems to be adding a lot of dbus match rules without removing them when opening the date menu. This results in dbus error messages like this getting spammed in the journal:
[system] Connection ":1.329" is not allowed to add more match rules (increase limits in configuration file if required; max_match_rules_per_connection=2048)
If I run sudo dbus-monitor --system
I can see lots of match rules relating to dconf keys for gweather being added by gnome-shell, but seemingly never removed. This is what happens when opening the date menu:
method call time=1520552192.428820 sender=:1.329 -> destination=org.freedesktop.DBus serial=706 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=AddMatch string "type='signal',interface='ca.desrt.dconf.Writer',path='/ca/desrt/dconf/Writer/local',arg0path='/org/gnome/GWeather/'" method return time=1520552192.428854 sender=org.freedesktop.DBus -> destination=:1.329 serial=645 reply_serial=706
This rule gets added 95 times every time the menu is opened.
Other dconf keys cause match rules to be added as well, for example the window switcher adds a single match rule every time it is shown. These however seem to be getting removed when I manually trigger garbage collection via looking glass (and probably would also be removed when automatically garbage collected). The ones relating to gweather seem to stay around even after manual gc. And once the limit of 2048 rules is reached after opening the date menu a couple of times, every time the window switcher is shown or anything else that would add another rule results in the above dbus error message.