Re: Tree-sitter maturity

[Eli Zaretskii <eliz@gnu.org>]

> From: Yuan Fu <casouri@gmail.com>
> Date: Tue, 17 Dec 2024 14:11:51 -0800
> Cc: Peter Oliver <p.d.oliver@mavit.org.uk>,
>  Stefan Kangas <stefankangas@gmail.com>,
>  Emacs Devel <emacs-devel@gnu.org>,
>  Eli Zaretskii <eliz@gnu.org>
> 
> >> It’s also worth noting that Tree-sitter itself is somewhat immature; the developers say that until it reaches version 1.0, we should be wary of potentially unannounced incompatible changes (although they are trying harder to avoid this, over time).
> > 
> > 
> > [1] https://build.opensuse.org/package/show/editors/tree-sitter
> 
> I wonder if we can formalize a way for tree-sitter major modes to state the compatible version of language grammar it uses. Maybe a package.el cookies, or a variable that set, or even just comments in the beginning of the file.
> 
> Many major modes already adds entries to treesit-language-source-alist, that could be a good option too.
> 
> I especially want built-in major modes to give a version, so that packagers can package Emacs with the right version of tree-sitter grammar. I know Eli has problems with pinning a grammar version for builtin modes before, but I wonder what’s he’s stance now?

What's changed?

Many language grammars don't make official releases and thus don't
have versions.  Moreover, AFAIK there's no API to determine the
version of the grammar library we load.  So how can we manage such
version-pinning in a way that (a) is up-to-date, and (b) doesn't
preclude people from using a grammar library due to false negatives?