bug#61235: 30.0.50; tree-sit: `treesit-node-check' lacks a way to tell if a node belongs to a deleted parser

[Eli Zaretskii]

> From: Yuan Fu <casouri@gmail.com>
> Date: Mon, 6 Feb 2023 20:55:38 -0800
> Cc: Mickey Petersen <mickey@masteringemacs.org>,
>  61235@debbugs.gnu.org
> 
> >>> Yuan, any reason not to extend treesit-node-check instead?
> >> 
> >> I did extend treesit-node-check in the patch. But I also added a function 
> >> treesit-parser-live-p, which makes the same check but directly on a 
> >> parser. It just made sense to me that if we let treesit-node-check check 
> >> the nodes’ parser’s status, we’d also add a function to allow directly 
> >> checking the status of a parser.
> > 
> > That additional function would signal an error in the case discussed
> > here, so I'm not sure we should add it in that shape, or at all.  Why
> > isn't treesit-node-check enough?
> 
> Oops, it shouldn’t have. The updated patch fixes that. Treesit-node-check is 
> enough, it just made more sense implentattion-wise, to implement that 
> function that checks a parser, and let treesit-node-check use that function 
> to check the node’s parser. We can choose to not expose that function, and 
> only expose this feature through treesit-node-check, if you prefer so.

I think treesit-node-check alone should be enough.

One comment:

> @@ -1943,9 +1959,11 @@ DEFUN ("treesit-node-check",
>      result = ts_node_is_extra (treesit_node);
>    else if (EQ (property, Qhas_error))
>      result = ts_node_has_error (treesit_node);
> +  else if (EQ (property, Qlive))
> +    result = Ftreesit_parser_live_p (XTS_NODE (node)->parser);

Ftreesit_parser_live_p returns a Lisp object, whereas 'result' is a C
'bool' type.  This won't compile if you configure with
"--enable-check-lisp-object-type".