bug#31325: 27.0.50; PROPOSAL: introduce a new function to recenter without redisplaying the frame

[Stefan Monnier <monnier@iro.umontreal.ca>]

> This BUG is a continuation of this help-gnu-emacs mailing list
> thread [1]. As mentioned in the thread, I ran into a terminal flickering
> issue in flycheck which turns out to be caused by `recenter'
> redisplaying the frame when `recenter-redisplay' value is either `t' or
> `tty'. I agree with the arguments in the thread to maintain the backward
> compatible behavior. Instead, I'm proposing one of the following
> alternatives:

Indeed, most/all uses from Elisp shouldn't redisplay.

> 1. introduce a new lisp function for recentering and discourage the use
> of `recenter' from lisp (i.e. declaring it `interactive-only'), or
> 2. add a new `recenter-and-redisplay' and bound it to C-l
> Also, Stefan's suggestion/possible solution:
> 3. adding an argument to `recenter' to control the redisplay behavior

Either of those is OK.  The benefit of the 3rd is that it would likely
"magically fix" 99% of the existing uses (I'm thinking of adding an
optional argument which we could call `and-redisplay` which when non-nil
tells recenter to do a redisplay, so all existing Elisp calls would be
implicitly modified not to cause a redisplay).


        Stefan