bug#63187: 30.0.50; Tail of longer lines painted after end of nearby lines on macOS

[Kai Ma]

> On Jun 9, 2023, at 10:47, Aaron Jensen <aaronjensen@gmail.com> wrote:
> 
> On Thu, Jun 8, 2023 at 10:42 PM Kai Ma <justksqsf@gmail.com> wrote:
>> 
>> Increasing CACHE_MAX_SIZE alone doesn’t seem to help much.
>> (Screencast: https://www.youtube.com/watch?v=9YD9jyP-GKw)
>> 
>> Increasing CACHE_MAX_SIZE + Removing performSelectorOnMainThread seems to be 
>> better but I can’t be sure.  Just observed:
>> 
>> (1) M-< at the mid of a buffer, but only the first line of the view is 
>> refreshed, and other parts were still there.
>> 
>> (2) selecting a region doesn’t always clear the hl-line effect.
> 
> What are you doing to make your background translucent? I've never
> seen anything nearly as bad as what you have. I've only seen a glitch
> maybe once since the last patch (and that may have even been something
> else). It makes me wonder if there's something else different/off
> about your setup.

(set-frame-parameter nil 'alpha 0.95)

Indeed I haven’t been able to reproduce this bug in emacs -q so far. I thought 
I didn’t do anything unconventional, but, well, polling-period seems to be the 
culprit.

I had in my config
  (setq polling-period 0.01)
to increase the responsiveness of C-g, and reverting the change to the default 
value 2.0 is effective.