bug#60453: 29.0.60; treesit-range-rules throw an error without tree-sitter

[Wilhelm Kirschbaum]

Eli Zaretskii <eliz@gnu.org> writes:

> > From: Wilhelm Kirschbaum <wkirschbaum@gmail.com>
> > Date: Sat, 31 Dec 2022 16:53:08 +0200
> >
> >
> > With the following code without tree-sitter library:
> >
> > (defvar elixir-ts-mode--treesit-range-rules
> >   (treesit-range-rules
> >    :embed 'heex
> >    :host 'elixir
> >    '((sigil (sigil_name) @name (:match "^[H]$" @name) 
> >    (quoted_content)
> >   @heex))))
> >
> > upon loading the mode I get the following error:
> >
> > treesit-range-rules: Symbol’s function definition is void:
> > treesit-query-compile
> >
> > This can easily be mitigated with (when 
> > (treesit-available-p)...)
> > but think it should function similar to how 
> > (treesit-font-lock-rules
> > work.
>
> Why does it make sense to protect treesit.el's code with
> treesit-available-p?  You aren't supposed to use treesit.el 
> functions
> when the tree-sitter library is not available.  IOW, Lisp 
> programs
> that want to use treesit-range-rules and other functions from
> treesit.el should make the treesit-available-p test _before_ 
> that.

Okay, that makes sense.  I just saw this comment on

;; treesit.el#618
(defun treesit-font-lock-rules (&rest query-specs)
 ...
 ;; Other tree-sitter function don't tend to be called unless
 ;; tree-sitter is enabled, which means tree-sitter must be 
 compiled.
 ;; But this function is usually call in `defvar' which runs
 ;; regardless whether tree-sitter is enabled.  So we need this
 ;; guard.
 (when (treesit-available-p)

As treesit-range-rules also gets called with defvar and it is a 
consistency
issue.  I think the reason why this has not popped up before is 
that no
other modes I have seen uses treesit-range-rules yet and think it 
will
probably catch people off guard in the future.