We could use some help improving the timestamp printing/parsing in parseedn.el https://github.com/clojure-emacs/parseedn/issues/8

I have an issue in my emacs (27.1 from https://github.com/railwaycat/homebrew-emacsmacport) where emacs sometimes hangs when I want to undo a change. I see a spinning beachball for ~20 seconds or more. It sometimes recovers, sometimes it doesn’t and I need to kill it. Anybody have any tips or useful resources for how to debug this?

Are you using undo-tree?

yes

should I try getting rid of it? I also read about sending emacs SIGUSR2 but it stayed frozen…

undo-tree seems to be pretty buggy, I've experienced the same thing you're seeing, with it completely locking up and the only option being to kill emacs. I switched to undo-fu instead. It's much more basic and there are times where it seems to forget a lot of the undo history and only allow you to go back a few steps, but at least it doesn't hang.

in spacemacs you can't get rid of undo-tree completely, but you can disable it

(global-undo-tree-mode -1)
  (define-key evil-normal-state-map "u" #'undo-fu-only-undo)
  (define-key evil-normal-state-map "\C-r" #'undo-fu-only-redo)

and add undo-fu to dotspacemacs-additional-packages

@plexus will give it a try, thank you!