GNU bug report logs - #61529
30.0.50; tree-sitter: weird off-by-one error but only in css-ts-mode(?) with `treesit-node-at'

Previous Next

Full log

Message #26 received at 61529 <at> debbugs.gnu.org (full text, mbox):

From: Dmitry Gutov <dgutov <at> yandex.ru>
To: Mickey Petersen <mickey <at> masteringemacs.org>,
 Theodor Thornhill <theo <at> thornhill.no>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 61529 <at> debbugs.gnu.org
Subject: Re: bug#61529: 30.0.50; tree-sitter: weird off-by-one error but only
 in css-ts-mode(?) with `treesit-node-at'
Date: Thu, 16 Feb 2023 23:26:06 +0200

On 15/02/2023 21:01, Mickey Petersen wrote:
> I read and interpreted it to mean that due to how node boundaries work
> that "*end is at*  or after POS" to mean that point is wholly contained
> in the node "(" which, due to how tree-sitter determines node extents,
> it technically isn't.
> 
> But I think it's fair enough if this is intentional -- I've no real
> suggestions for improving its behaviour if this is intended. So if
> it's working as expected, then it's safe to close the issue.

The difference in this case is due to the tree structure:

In '210deg', (integer_value) is not a leaf node. The only leaf node it 
has inside is (unit), and that one starts 3 characters later.

In '255', however, (integer_value) *is* a leaf node. And since 
treesit-node-at looks for leaf nodes, it stops at "(" as documented.

I'd probably calls it a problem with the grammar, but it doesn't seem 
likely to be fixed, backward compatibility and all.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.