bug#38067: Command Popup Hangs Emacsclient During Startup

[Eli Zaretskii <eliz@gnu.org>]

> From: Gustaf Waldemarson <gustaf.waldemarson@gmail.com>
> Date: Tue, 5 Nov 2019 10:31:10 +0100
> 
> I've run into a slightly annoying issue with the emacsclient hanging
> during startup due to it being unable to display a command prompt. To
> recreate the behavior:
> 
> 1. create a file with the contents (e.g., init.el):
> 
> ,----
>  (defun my-hang-client ()
>    "This is a test function."
>    (condition-case nil
>        (let* ((choices (list
>                        "This function seems to hang Emacsclient."))
>               (result (completing-read "This is a hang test:" choices nil t))
>               (index (cl-position choices :test 'equal))))
>      ('quit)))
> 
>  (add-hook 'c-mode-hook      #'my-hang-client)
>  (add-hook 'c++-mode-hook    #'my-hang-client)
> `----
> 
> 1. Start a new Emacs server: `emacs --load init.el -Q --daemon=hangtest'
> 
> 2. Open a new C/C++ file from the terminal (doesn't need to exist):
>    `emacsclient -nc -s hangtest main.cpp'

Can you try this with the latest master branch?  I think the cause of
this was lately fixed.

Thanks.