bug#75056: 31.0.50; tty-child-frames with server / multiple clients possible hangs

[Gerd Möllmann]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Len Trigg <lenbok@gmail.com>
>> Date: Tue, 24 Dec 2024 18:43:29 +1300
>> 
>> tty-child-frames does not seem to play well with multiple clients. When we 
>> run server-start and allow emacs to
>> have multiple clients (e.g. an initial "emacs -nw" and an
>> "emacsclient -nw"), using a function that utilizes tty-child-frame (such as 
>> M-x when vertico-posframe is
>> loaded) in one frame leads the other client to be locked up.
>> 
>> Steps to reproduce:
>> 
>> mkdir ~/emacs-test
>> Copy the attached init.el into ~/emacs-test/
>> emacs -nw --init-directory=~/emacs-test  (the first time will result in 
>> packages being installed by elpaca)
>> (in another terminal) emacsclient -nw
>> Do something to invoke the child frame pop up (e.g. C-x b and select a 
>> buffer)
>> Switch back to the original emacs
>> Do something to invoke the child frame pop up (e.g. C-x b and select a 
>> buffer)
>> Swap to the other terminal, and note that at some point one client will stop 
>> responding
>> to user input. (It may take a couple of tries, perhaps with other regular 
>> commands interspersed).
>> When one client is locked, swap back to the other terminal and exit the 
>> client - the original
>> client will now accept user input.
>> 
>> When a client is locked it *does* accept some input (e.g. C-x C-c will exit 
>> the client)
>> 
>> It's possible this is vertico-posframe related, as I can't trigger similar 
>> behaviour using transient-posframe.
>
> Gerd, could you perhaps look into this?

Thanks. Will come back to this after the holidays.