bug#61617: M-x mark-defun doesn't work correctly in tree-sitter modes when comments exist between functions

[Evgeni Kolev]

Great, thanks for the fix! I tested a few common (for me) scenarios
and mark-defun works as expected!

On Mon, Feb 27, 2023 at 11:24 AM Yuan Fu <casouri@gmail.com> wrote:
>
>
>
> > On Feb 26, 2023, at 4:42 PM, Yuan Fu <casouri@gmail.com> wrote:
> >
> >
> >
> >> On Feb 24, 2023, at 11:27 PM, Evgeni Kolev <evgenysw@gmail.com> wrote:
> >>
> >> On Sat, Feb 25, 2023 at 7:08 AM Yuan Fu <casouri@gmail.com> wrote:
> >>
> >>> Huh, with or without comments, mark-defun always includes the empty
> >>> lines before the defun for me. I get the same behavior in rust-ts-mode.
> >>> This seems intentional, because this is at the end of the definition of
> >>> mark-defun:
> >>>
> >>> (skip-chars-backward "[:space:]\n")
> >>> (unless (bobp)
> >>> (forward-line 1))
> >>
> >> Did you check with my example or another example? With my example, the
> >> issue I get is that only the empty lines are marked, without the
> >> defun, without the comments. I'm attaching two screenshots - before
> >> and after mark-defun.
> >>
> >> Note: I get the correct behaviour when there is just one defun in the
> >> file. But if there are more, or the defun at point is not at the top
> >> of the file - mark-defun does not work as expected.
> >
> > Sorry, I used wrong go mode when testing your recipe. I used go-mode 
> > thinking it is go-ts-mode :-( Using go-ts-mode, I can reproduce what you 
> > see, yes.
> >
> > The problem you discovered revealed some shortcoming in our tree-sitter 
> > navigation function, and requires quite a few non-trivial changes, I 
> > working on fixing it.
> >
> > The direct cause is that (treesit-beginning-of-defun -1) is supposed to go 
> > to the beginning of next defun, but instead goes to the beginning of next 
> > next defun. That was a design decision I made but I can see it causing old 
> > functions to misbehave.
> >
> > Yuan
>
> The fix is brain-twisting but don’t embody a lot of code, yay! This now 
> should be fixed.
>
> Yuan