bug#60961: 29.0.60; Compiling emacs-29 without treesitter outputs warnings

[Eli Zaretskii <eliz@gnu.org>]

> From: Theodor Thornhill <theo@thornhill.no>
> Cc: 60961@debbugs.gnu.org
> Date: Fri, 20 Jan 2023 14:50:22 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Yes, I've seen these as well.  The reason is that some modes 'require'
> > c-ts-mode, because they want to use their comment-related functions.
> > But the changes I made recently call treesit-ready-p when c-ts-mode is
> > being loaded, and that emits the warning.  I can shut up the warning
> > by calling treesit-ready-p with a non-nil QUIET argument, but then the
> > warning will not be emitted if users load c-ts-mode from their init
> > files or manually, which is not good.  I tried several other
> > solutions, but they either didn't work or were not clean enough for my
> > palate.
> >
> > Yuan/Theo, please find a solution for this.  If no better idea comes
> > up, I think the c-ts-mode functions that other modes want to use
> > should be moved to a separate file, and that file that can be
> > 'require'd by all those which want it, including by c-ts-mode.el.
> >
> 
> Yeah, I was hoping to actually just allowing some duplication of code,
> until some "best practice" emerges the coming months, and we can make a
> treesit-common-lib.el or something like that.
> 
> So I can either just make sure that no modes require across modes, or
> make that "lib" right now.  What do you think?

I tend to the "lib" method.  Mostly because several modes, including
some that are unrelated to C, want the code which was written for
C/C++, and so it is possible that there's some general feature here
waiting for us to refactor the code -- in which case perhaps the code
should be in treesit.el?

IOW, how come JS, Rust, and Typescript all want comment-related setup
that was written for C?  If this is just a coincidence, then perhaps
duplicating the code is a better idea, but if there's some underlying
commonality, we should have common code in treesit.el, or maybe in
some c-ts-common.el?