Re: Eglot "inlay hints" landed

[Eli Zaretskii <eliz@gnu.org>]

> From: João Távora <joaotavora@gmail.com>
> Date: Thu, 23 Feb 2023 17:46:08 +0000
> Cc: dalal.chinmay.0101@gmail.com, emacs-devel@gnu.org, dimitri@belopopsky.com, 
> 	luangruo@yahoo.com
> 
> > That's no for jit-lock to do.  And I don't see how it could be
> > relevant to the issue we are discussing.  How do you do this now?
> 
> I don't.  I was just pointing out that jit-lock by itself doesn't
> solve this A -> B dependency, which you seemed to suggest it does when
> you wrote:
> 
> > > If there's a change in A that affects B, jit-lock will call
> > > fontification-functions in both A and B, each one when it's about to
> > > display the corresponding window.

That was written under the assumption that the overlays in B are
already updated.  Then redisplay will know it must redraw B.

> > window-scroll-functions cannot promise that, since
> > they are only called "when the window is scrolled", and there's more
> > to that condition than meets the eye, believe me.
> 
> I believe you.  But as far as I can tell so far, it's the least
> imperfect of the methods, and I haven't seen demonstrations of
> problems so far, only your speculation of hypothetical problems.

I actually gave you a recipe for demonstrating the problems I have in
mind: scroll the window under pixel-scroll-precision-mode.  AFAIK, we
don't call window-scroll-functions in that case.

Another situation where we don't call window-scroll-functions is when
the user types into the buffer.

Yet another situation is when you type "C-x 1" to delete all the other
windows on the frame, leaving the current window that now shows more
stuff than before.

> I'd love to switch over to the jit-lock implementation as it has
> potential to be much neater.  But I can't seem to get it to not
> over-request stuff. I attach the patch I've been trying, and it's
> clearly got some thinkos when you test it.  It doesn't help that
> `window-start` and `window-end` aren't -- apparently -- reliable
> when called from a jit-lock function.

Sorry, I don't have time for that ATM, but maybe Stefan will want to
comment.