Add hook for after startup?

[BettaGeorge]

From scouring StackOverflow I know that I am not the only person with this problem: you have some program you want to run that depends on your login flow actually being complete, or you have a startup program that insists on opening a window and you just want EXWM to close that buffer rather than having to press C-x C-k every time after you log in.

Neither exwm-init-hook nor emacs-startup-hook nor window-setup-hook run late enough to facilitate this. They all complete long before exwm-xrandr has finished sorting through my displays.

Is it possible to detect at which point in time EXWM is actually done "doing" stuff and is ready for user input? In which case, can we add a hook for us to use?

If not, how do other people solve this problem without resorting to a hard coded five second timer after login?

[Stebalien]

The exwm-init-hook runs after setting everything up and right before managing existing windows. That should be late enough to start something.

If you need to wait for your entire "login flow" to complete, that's not something EXWM is going to be able to do. It doesn't know when autostarted apps are going to be done launching.

If you just want to close an app when it first opens a window, you'll have to hook into exwm-manage-finish-hook. At that point, you can look at the current buffer's exwm-class-name, exwm-title, etc. and delete the offending buffer. If you only want this to happen "on startup", you can have the hook delete the buffer then remove itself from exwm-manage-finish-hook.

[BettaGeorge]

That makes sense, and I could have thought about that point before posting. Thank you!

[BettaGeorge]

For anyone who might come across this in the future: exwm-manage-finish-hook works, but with some caveats. The following code technically works. In this example, I want to close the main window of the screenshot manager shutter after it autostarts. (shutter has an option to not open the window on autostart, but that option has not worked for many versions now.)

  (defun shutterkiller ()
    "Hook into exwm-manage-finish-hook to kill the first shutter buffer"
    (when (string= "Session - Shutter" exwm-title)
      (remove-hook 'exwm-manage-finish-hook 'shutterkiller)
      (kill-buffer "Session - Shutter")
  ))
  (add-hook 'exwm-manage-finish-hook 'shutterkiller)
  (start-process "" 
     	       nil "shutter")

Regrettably, EXWM is convinced that the buffer containing the X window is attached to a process and tries to send a SIGHUP to that process. This fails, because shutter runs in the background and is independent from the window. EXWM's kill-buffer hook times out (which takes a few seconds during which EXWM freezes entirely) before informing you that shutter is not responding; would you like to kill it?. Responding y to this query sends a SIGKILL to a nonexistent process (which is harmless) and finally closes the window.

As far as I can tell, EXWM provides no utility to force-close a window, so I had to hack the source itself. I actually use something very close to the snippet above:

  (setq exwm-kill-buffer-query-function-override nil)
  (defun shutterkiller ()
    "Hook into exwm-manage-finish-hook to kill the first shutter buffer"
    (when (string= "Session - Shutter" exwm-title)
      (remove-hook 'exwm-manage-finish-hook 'shutterkiller)
      (let ((exwm-kill-buffer-query-function-override t))
        (kill-buffer "Session - Shutter"))
      ))
  (add-hook 'exwm-manage-finish-hook 'shutterkiller)
  (start-process "" 
     	       nil "shutter")

And then I have simply modified the last few lines of exwm-manage--kill-buffer-query-function:

        (unless exwm-kill-buffer-query-function-override
  	(with-timeout (exwm-manage-ping-timeout
                         (if (y-or-n-p (format
  				      "'%s' is not responding.  \
  Would you like to kill it? "

                                        (buffer-name)))
                             (progn (exwm-manage--kill-client id)
                                    ;; Kill the unresponsive X window and
                                    ;; wait for DestroyNotify event.
                                    (throw 'return nil))
  			 ;; Give up.
  			 (throw 'return nil)))
            (while (and exwm-manage--ping-lock
                        (exwm--id->buffer id)) ;may have been destroyed.
              (accept-process-output nil 0.1))
            ;; Give up.
            (throw 'return nil))))))

Not pretty, and it flashes a bunch upon login (especially if you do this to more than one startup program), but it keeps my buffer list clean.