bug#69952: [PATCH] Support pdumping compiled queries by dumping their source

[Yuan Fu]

> On Apr 20, 2024, at 9:53 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Yuan Fu <casouri@gmail.com>
>> Date: Sat, 20 Apr 2024 15:50:36 -0700
>> Cc: Daniel Colascione <dancol@dancol.org>,
>> serg.foo@gmail.com,
>> 69952@debbugs.gnu.org
>> 
>>>>> On Apr 13, 2024, at 12:41 AM, Eli Zaretskii <eliz@gnu.org> wrote:
>>>>>> 
>>>>>> And I have a question: what happens if the pdumper file dumped with
>>>>>> tree-sitter available is loaded by an Emacs session in which
>>>>>> tree-sitter is not available?  That can happen on Windows, for
>>>>>> example, if the tree-sitter library or the grammar library required
>>>>>> for recomputing the query is not available.  I think we need some code
>>>>>> to prevent Emacs from crashing on startup in that case.
>>>> 
>>>> Yeah, being able to dump queries is certainly nice. There will be problems 
>>>> if the Emacs session that later loads the query either have a different 
>>>> grammar version loaded, or a difference grammar library for the same 
>>>> language, or outright doesn’t have tree-sitter like Eli mentioned. I don’t 
>>>> know if they are big enough problems to give up dumping queries, though.
>>> 
>>> Giving up: no.  But I think the code which loads the queries from the
>>> pdumper file should be protected from crashing in those cases.  Can
>>> you suggest how to do that?
>> 
>> Would Emacs crash? If the dump file just contains the query (which is a 
>> string), then Emacs would just compile the query with treesit-query-compile, 
>> it could fail (due to the reasons I mentioned), but shouldn’t crash Emacs.
> 
> Can Emacs compile a query if the tree-sitter shared library and/or the
> grammar library is not available?

No. You need both tree-sitter library and the grammar library.

Yuan