Closing last wezterm window should not terminate the mux server (by design?)

[xunnanxu]

Describe the bug

Closing the last window somehow would terminate the mux server today.

Caused by:
    Connection refused (os error 111)

 2021-04-03T20:56:44.087Z INFO  wezterm_gui::termwindow > OpenGL initialized! Mesa Intel(R) UHD Graphics 620 (KBL GT2) OpenGL ES 3.2 Mesa 20.2.2 is_context_loss_possible=false wezterm version: 
 2021-04-03T20:56:44.095Z ERROR wezterm_gui             > connecting to <hostname>: Connection refused (os error 111); terminating
 2021-04-03T20:56:44.095Z ERROR mux::connui             > while running ConnectionUI loop: recv_timeout: channel is empty and disconnected

Environment (please complete the following information):

• OS: Fedora 32 client side + CentOS 8 server
• Version: client: master build, server: wezterm 20210314-114017-04b7cedd-124-gb057e1f6

To Reproduce

Enable multiplexing:

server:

WEZTERM_LOG=trace wezterm-mux-server --daemonize 2> /tmp/server.txt

client:

wezterm connect <name>

After connection is established, ctrl d to terminate the session and close the window.

Reconnect and connections is refused. Check server side the mux server is not running any more.

Configuration

don't think this is actually relevant here

Expected behavior

The server process should not quit and reconnection should be successful.

Additional context

tail -f /tmp/server.txt
2021-04-03T20:54:01.001Z TRACE polling::epoll > new: epoll_fd=4, event_fd=5, timer_fd=Some(6)
2021-04-03T20:54:01.001Z TRACE async_io::driver > main_loop: waiting on I/O
2021-04-03T20:54:01.001Z TRACE async_io::reactor > process_timers: 0 ready wakers
2021-04-03T20:54:01.001Z TRACE polling > Poller::wait(_, None)
2021-04-03T20:54:01.001Z TRACE polling::epoll > wait: epoll_fd=4, timeout=None
2021-04-03T20:54:01.001Z TRACE polling::epoll > modify: epoll_fd=4, fd=6, ev=Event { key: 18446744073709551615, readable: true, writable: false }
2021-04-03T20:54:01.006Z DEBUG config > Reloaded configuration! generation=1
2021-04-03T20:54:01.007Z TRACE mio::poll > registering with poller
2021-04-03T20:54:01.007Z TRACE mio::poll > registering with poller
2021-04-03T20:54:01.007Z TRACE mio::poll > registering with poller

[wez]

Yeah, that's a fair request. This behavior was by design, but that design was from when the mux server was a separate front-end within the same binary as the GUI.

[xunnanxu]

Thanks for the quick fix @wez ! There's one remaining minor issue:
If I close the window directly, things are fine.
If I ctrl D to terminate the session first and then close the window, I get an error saying client is destroyed.

After some digging it seems like the actual error is receiving from an empty and closed channel. Seems like we need to add a check to not send close when a session is already terminated when window is closed.

[wez]

I couldn't directly reproduce this, but I did just push a commit that might help. Let me know how it works out!

[no-response]

This issue has been automatically closed because there has been no response to the request for more information from the original author. With only the information that is currently in the issue, there isn't enough information to take further action. Please reach out if you have or find the answers we need so that we can investigate further.

[github-actions]

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