Subject: bug#78703: beginning-of-defun and friends still wrong in typescript-ts-mode

From: Troy Brown <[email-masked]>
Date: Fri, 6 Jun 2025 13:00:22 -0400

Daniel Colascione <[email-masked]> writes:

> On June 6, 2025 12:23:23 AM PDT, Yuan Fu <[email-masked]> wrote:
>>
>>
>>> On Jun 6, 2025, at 12:01 AM, Eli Zaretskii <[email-masked]> wrote:
>>>
>>>> From: Daniel Colascione <[email-masked]>
>>>> Date: Thu, 05 Jun 2025 16:40:03 -0700
>>>>
>>>> Right now, C-M-a runs treesit-beginning-of-defun which goes to the
>>>> start of the previous defun in buffer text, not the enclosing defun.
>>>>
>>>> If we have this program:
>>>>
>>>>    1 function foo() {
>>>>    2   function bar() {
>>>>    3     return 5
>>>>    4   }
>>>>    5   return 7
>>>>    6 }
>>>>
>>>>
>>>> and point is on line 5, then if we hit C-M-a, point goes to line 2, not
>>>> line 1.  In every single situation, when I use beginning-of-defun, I
>>>> intend to go to the start of my enclosing defun not the one that happens
>>>> to be previous in buffer linearization.
>>>
>>> I think you want to set treesit-defun-tactic to 'top-level’.
>>
>>Yes. Most likely top-level is what you want.
>>
>>Yuan
>>
>>
>
> I don't think that's right either --- if I'm on line 3, I should go to
> line 2, not 1. Go to beginning of defun should mean go to the
> beginning of *my* defun. That's the traditional behavior from cc-mode,
> js-mode, etc. and the one that makes most sense. I can see top-level
> being an option, but I don't think the way nested works right now is
> useful and it's confusing and inconsistent as a default.

I agree.  This behavior is not intuitive at all.  I reported this in
detail in Bug#68664, but it never seemed to go anywhere.  Furthermore,
using a `treesit-defun-tactic` of `top-level` doesn't work when you
are arbitrarily nested and just want to go to the beginning of the
function containing point.

This behavior not only impacts interactive use of
`treesit-beginning-of-defun` (via "C-M-a"), but other functionality
which builds upon `beginning-of-defun`, most notably
`prog-fill-reindent-defun`.  For the Tree-sitter modes that I
maintain, I had to create a mode-specific version of
`prog-fill-reindent-defun` instead.  That's because, as written,
`prog-fill-reindent-defun` uses `beginning-of-defun`, and since in
cases like this, `treesit-beginning-of-defun' goes to the previous
nested function, rather than the function containing point, you end up
re-indenting the previous nested function rather than the function
containing point.  The mode-specific version that I created, instead
uses `treesit-defun-at-point` to locate the containing function.