bug#60559: 29.0.60; "Cannot activate tree-sitter" spam

[Stephen Berman]

On Wed, 04 Jan 2023 22:10:47 +0200 Eli Zaretskii <eliz@gnu.org> wrote:

>> From: Stephen Berman <stephen.berman@gmx.net>
>> Cc: Eric Gillespie <epg@pretzelnet.org>,  60559@debbugs.gnu.org
>> Date: Wed, 04 Jan 2023 20:59:04 +0100
>>
>> >>   Warning (treesit): Cannot activate tree-sitter, because
>> >>   tree-sitter library is not compiled with Emacs
>> >
>> > This is not a bug.  Emacs 29 comes with major modes for TOML files and
>> > for Dockerfiles, and those new major modes require that you build
>> > Emacs with the tree-sitter library (and install the corresponding
>> > parser grammar libraries).  If you don't want to do that, you can
>> > instead customize auto-mode-alist to make Emacs use Fundamental mode
>> > (or any other mode you like) for these two file types.
>>
>> Emacs 28 already has conf-toml-mode for TOML files, so shouldn't
>> toml-ts-mode be handled like e.g. c-ts-mode instead of being added to
>> auto-mode-alist? (The default value of that variable in Emacs 29 still
>> contains an entry for conf-toml-mode, lower down than the entry for
>> toml-ts-mode.)
>
> We could indeed do that for TOML files, but I believe the problem
> raised here is more general.

That may be, but the TOML case appears to be a regression, since
visiting a TOML file in Emacs 28 displays various faces but visiting a
TOML file in Emacs 29 without having the tree-sitter TOML grammar
library installed displays only the default face.  But if fixing the
more general problem in Emacs 29 also fixes this apparent regression,
then of course that's better than an ad hoc fix.

Steve Berman