Subject: bug#73404: 30.0.50; [forward/kill/etc]-sexp commands do not behave as expected in tree-sitter modes

From: Mickey Petersen <[email-masked]>
Date: Sat, 21 Sep 2024 06:06:58 +0100

Examples with javascript-mode. It holds for all modes i tested with a
TS equivalent. Let -!- be the starting point and ^N be the subsequent
position after a movement command.

-!-export const add = (a, b) => a + b;

Repeated `C-M-f' yields

export const add = (a, b) => a + b;

      ^1    ^2  ^3       ^4   ^5  ^6

In other words, it works as it always has.

Meanwhile, in `js-ts-mode':

export const add = (a, b) => a + b;
                ^1       ^2   ^3  ^4

>From ^1 and back with `C-M-b'

export const add-!- = (a, b) => a + b;

export const add = (a, b) => a + b;
             ^1

At this point, `C-M-b' no longer goes back. It is stuck.

Another example:

-!-console.log("Addition result:", result1);

With `C-M-f':

console.log("Addition result:", result1);

       ^1                               ^2

This affects every single -sexp function that uses either
`forward-sexp-function' or `transpose-sexp-function' to do its job.

Thanks.