bug#62333: 30.0.50; Issue with tree-sitter syntax tree during certain changes

[Dmitry Gutov]

17:57, 25 March 2023, Eli Zaretskii <eliz@gnu.org>:

 Date: Sat, 25 Mar 2023 17:25:17 +0200
 Cc: wkirschbaum@gmail.com, casouri@gmail.com, 62333@debbugs.gnu.org
 From: Dmitry Gutov <dgutov@yandex.ru>
 
 On 25/03/2023 16:41, Eli Zaretskii wrote:
 >> Date: Sat, 25 Mar 2023 16:18:12 +0200
 >> Cc: wkirschbaum@gmail.com, casouri@gmail.com, 62333@debbugs.gnu.org
 >> From: Dmitry Gutov <dgutov@yandex.ru>
 >>
 >>> mixed-major-mode shouldn't be a problem.
 >>
 >> Why wouldn't it?
 >
 > Because the sexp ends inside the current mode's block.
 
 But if the mmm framework narrowed the region to the current mode's
 block, widening will force tree-sitter to parse the whole buffer.

No, because such a mode mode should already make sure this doesn't
happen.

How?

 >> Okay. But do you advocate all uses of tree-sitter to (widen) first?
 >
 > No, just in sexp-movement functions, at least for now. If we discover
 > this is need in many more situations, we might consider more drastic
 > measures. But I don't think we are there yet. We've discovered just
 > one such case, in just one such mode, and it's on master. We still
 > have ample time to see how widespread this is.
 
 I'm not sure whether tree-sitter is going to be used with mmm-mode (or
 similar) a lot, since it has its own provisions for mixing languages.
 
 But I'd also like to consider the other cases where we *don't* want to
 widen first. Any of them come to mind?

No, not off the top of my head.

I think we should try this in this one case, and see if other cases
come up.

I think we should try to answer the relevant questions first.