Re: Tree-sitter maturity

[Björn Bidar]

Daniel Colascione <dancol@dancol.org> writes:

> On December 29, 2024 10:05:26 AM EST, "Björn Bidar"
> <bjorn.bidar@thaodan.de> wrote:
>>Daniel Colascione <dancol@dancol.org> writes:
>>
>>> On December 27, 2024 9:59:14 AM EST, Eli Zaretskii <eliz@gnu.org> wrote:
>>>>> Date: Fri, 27 Dec 2024 08:46:06 -0500
>>>>> From: Daniel Colascione <dancol@dancol.org>
>>>>> CC: rms@gnu.org, manphiz@gmail.com
>>>>> 
>>>>> >> It might take a while for that to happen, which is why I still
>>>>> >> believe
>>>>> >> it would be better if tree-sitter major modes would populate
>>>>> >> `treesit-language-source-alist' on their own, and point to the
>>>>> >> specific
>>>>> >> checkouts that the major mode developer tested their implementation
>>>>> >> against.
>>>>> >
>>>>> >We could have done that, but there's no way we could keep the value of
>>>>> >treesit-language-source-alist up-to-date, because the grammar
>>>>> >libraries put out new versions much more frequently than Emacs
>>>>> >releases, especially if you consider libraries that have no official
>>>>> >versions at all (in which case we can only point to some revision in
>>>>> >their repository).
>>>>> >
>>>>> >The question that bothers me is how useful is it to have
>>>>> >treesit-language-source-alist that is outdated?  What do we expect the
>>>>> >users to do with such an outdated value?
>>>>> >
>>>>> 
>>>>> Why not just vendor all the grammars with the Emacs modes that
>>>>> use them?
>>>>
>>>>We'd need to ask their developers to agree to this. 
>>>
>>> Why? They're free software. For copyright assignment? Seems like an
>>> exception would make sense here.
>>>
>>>> Other than that,
>>>>I don't see how is that different from pointing to a specific version
>>>>of each grammar: both will be outdated a short time after we point to
>>>>the version or release Emacs with that version.
>>>>
>>>>So why do you think this is better?
>>>
>>> Vendoring enables building a full featured Emacs without a network
>>> connection and guarantees build reproducibility in perpetuity.
>>
>>Did you think of the long term consequences?
>>
>>The embedded dependencies would have to be maintained first by Emacs and
>>later by packagers.
>>
>>All the infrastructure around syncing of grammars is time spend that
>>could spend on more long term efforts such as stabilizing the
>>tree-sitter based modes to not break as easy on grammar changes or to
>>improve tree-sitter it self.
>
> I've vendored plenty of things. Works fine in practice. Big programs
> like Firefox vendor the world too, and they work fine. It's really not
> that much work. It eliminates entire classes of problem. It's going to
> take more time to deal with the problems of taking a dependency and
> the headaches of not having a stable interface than it would to set up
> a few git subtrees or submodules and invoke their build system from
> that of Emacs.

Big programs like Firefox vendor the world only for packagers to have
to revert those. Vendoring only works long enough until the dependencies
you have vendored are not out of date. It is something which only works
in projects who control most of their dependency chain and/or have a
fire and forget approach of software development.

> It's not even the precise mechanics: pulling down a grammar by hash is
> tantamount to just checking in the grammar, but with more moving
> parts. You still pair one to one the grammar and the Lisp code meant
> to use it so you don't end up chasing down weird compatibility
> issues. IMHO, since they're tightly coupled anyway, we might as well
> distribute them together.
>
> As for changing TS grammars not to break: why do you think that would
> be feasible? So far TS grammar authors haven't felt particularly
> obligated to maintain compatibility.

I don't know exactly to be honst but I don't think we are alone with
this issue. If we are we should check out it is handled in other
editors.