If the python client can detect the BNC restart, a reasonable solution might be clearing self.joined_channels on that event. The current message send logic short circuits when the target channel is in the joined_channels list and would otherwise await a join command before proceeding.

If the python client can detect the rejected message send ([2026-03-20 01:14:38.903176] (wikibugs/libera) IRC -> ZNC [:tantalum.libera.chat 404 wikibugs #wikimedia-dev :Cannot send to nick/channel]) one reasonable solution would be a trap on that error that does a channel join and then resends.

In T410540#11734166, @bd808 wrote:

If the python client can detect the BNC restart, a reasonable solution might be clearing self.joined_channels on that event. The current message send logic short circuits when the target channel is in the joined_channels list and would otherwise await a join command before proceeding.

According to the examples at https://github.com/gawel/irc3/blob/main/examples/mybot.py, this seems to be doable in the server_ready (or even connection_lost?) methods.

If the python client can detect the rejected message send ([2026-03-20 01:14:38.903176] (wikibugs/libera) IRC -> ZNC [:tantalum.libera.chat 404 wikibugs #wikimedia-dev :Cannot send to nick/channel]) one reasonable solution would be a trap on that error that does a channel join and then resends.

Detecting the ERR_CANNOTSENDTOCHAN numeric is trivial, but the plumbing required to access the specific message text in the handler for that would not be. Also note that that numeric can be triggered for other reasons (like a channel being moderated) than just not being in there.

In T410540#11734265, @taavi wrote:

In T410540#11734166, @bd808 wrote:

If the python client can detect the BNC restart, a reasonable solution might be clearing self.joined_channels on that event. The current message send logic short circuits when the target channel is in the joined_channels list and would otherwise await a join command before proceeding.

According to the examples at https://github.com/gawel/irc3/blob/main/examples/mybot.py, this seems to be doable in the server_ready (or even connection_lost?) methods.

I wonder actually if with the bouncer in place it wouldn't just be simplest to always send the JOIN. I would expect the BNC to ack that nearly instantly. The JOIN short circuit may be an optimization that we can get along fine without.