[Question] Why all-the-icons-icon-for-mode create idle timers?

[stardiviner]

I have following config:

(defun *major-mode ()
  "The major mode, including process, environment and text-scale info."
  (if (cdr (assoc major-mode all-the-icons-mode-icon-alist))
      ;; (all-the-icons-icon-for-buffer)
      ;; (all-the-icons-auto-mode-match?)
      (all-the-icons-icon-for-mode major-mode :v-adjust -0.1 :height 1.0)
    ;; (all-the-icons-icon-for-file (buffer-file-name) :v-adjust -0.05 :height 1.0)
    (propertize (format-mode-line "%m" mode-name)
                'face 'mode-line-data-face)
    ))

And I execute helm-timers found there are some timers are from all-the-icons.

My question is why need to create those timers? After did some profiling with Emacs profiler. Found it might slow down performance a little. Is it really necessary?

[stardiviner]

I found why now, it is because memoize is used. (memoize 'all-the-icons-icon-for-mode).
Is this memoize must necessary? I don't know why all-the-icons for major-mode need to be updated by timer. Shouldn't it be buffer local and static?

[wyuenho]

Judging from memoize's source, looks it's there to implement some sort of poor-man's weakref. It basically runs the timer every 2 hours by default to free up memory. I would imagine this was put in place to speed up icon look ups from that flat list. Lots of linear searches are expensive.

[harizvi]

I just hit this issue, with my timers list showing 680 outstanding timers. I had visited a few large directories with dired! The reason I started looking was because Emacs was running "laggy", esp with ivy-switch-buffer acting weirdly. Just wondering if this is not considered a problem?

[mpereira]

Another one bumping into this. My Emacs currently has 2000 non-idle timers started by all-the-icons.

Would keeping an in-memory hash map cache of icons be sufficient as a performance-improving alternative?

[wyuenho]

Would keeping an in-memory hash map cache of icons be sufficient as a performance-improving alternative?

Perhaps. Care to submit a PR to replace memoize?

[yantar92]

Perhaps. Care to submit a PR to replace memoize?

As a simple solution, all-the-icons can set memoize-default-timeout to nil when defining memoized functions. The timers will not be created then. This should not cause any significant memory leaks since the number of possible function arguments is finite (and relatively small).

[mpereira]

@wyuenho I unfortunately don't have a lot of free time these days. Does it make sense to re-open this ticket for visibility?