Posframe lingers even when current buffer is changed

[anonimitoraf]

I've noticed that a posframe lingers when I switch buffers

Steps to reproduce:

• Save https://gist.github.com/anonimitoraf/cf33c5e768d840371ca67c1517290704 into init.el
• emacs -l init.el
• Open on init.el
• Move to line 5 (within add-to-list) while in normal mode. Posframe should show up
• Press g d (still in normal mode). Should bring you to the definition of add-to-list. Posframe unexpected lingers

[anonimitoraf]

Is this just a matter of hiding any shown posframes in window-configuration-change-hook?

[alexmurray]

We already hide it in window-configuration-change-hook - see https://github.com/alexmurray/flycheck-posframe/blob/master/flycheck-posframe.el#L143 and https://github.com/alexmurray/flycheck-posframe/blob/master/flycheck-posframe.el#L228 and https://github.com/alexmurray/flycheck-posframe/blob/master/flycheck-posframe.el#L161

Sometimes I can reproduce this too though but I am not sure how it is occurring at the moment... perhaps we need to just unconditionally add flycheck-posframe-hide-posframe to window-configuration-change-hook when flycheck-posframe is enabled rather than doing it only when showing the posframe...

[anonimitoraf]

Ohhh, I see. Just to put it out there, I've only started to use Emacs, but this feels to me like it might be a race condition? I'll see if I can debug later

[anonimitoraf]

I found out that changing: (add-hook hook #'flycheck-posframe-hide-posframe nil t) to (add-hook hook #'flycheck-posframe-hide-posframe nil nil) seems to fix the issue.

I read about that arg here: https://www.gnu.org/software/emacs/manual/html_node/elisp/Setting-Hooks.html

If local is non-nil, that says to add function to the buffer-local hook list instead of to the global hook list. This makes the hook buffer-local and adds t to the buffer-local value. The latter acts as a flag to run the hook functions in the default value as well as in the local value.

Are there downsides to adding this hook to the global hook list?

[flatwhatson]

It seems that window-configuration-change-hook runs buffer-local hooks for the buffer you've switched to, but not the buffer you've switched from. This means that flycheck-posframe-hide-posframe doesn't get called until you switch back to the buffer which was showing the posframe!

I think that @anonimitoraf's solution of using the global window-configuration-change-hook is reasonable.

[anonimitoraf]

Actually, in that case, the counterpart remove-hooks should target global too, i.e.:

    (remove-hook hook #'flycheck-posframe-hide-posframe t)
    (remove-hook hook #'flycheck-posframe-maybe-hide-posframe t)

from t -> nil

Alternatively, now that you bring up this point:

It seems that window-configuration-change-hook runs buffer-local hooks for the buffer you've switched to, but not the buffer you've switched from

Are there window-*-hooks that get applied on the buffer you switch from?

[flatwhatson]

Actually, in that case, the counterpart remove-hooks should target global too

Yep!

Are there window-*-hooks that get applied on the buffer you switch from?

You can read about the hooks for window events in the manual. Whether the window configuration hooks are run before or after a buffer has been switched isn't exactly clear, but it does mention that they run during redisplay, and it makes sense that redisplay would occur after switching buffer and not before.

I really think that the global window-configuration-change-hook is the correct choice here to hide the posframe on the next window-modifying event.

[alexmurray]

This should be fixed now (thanks @anonimitoraf) - I will close this for now but feel free to reopen if it you see this again.