bug#66732: tree-sitter fontification doesn't update multi-line syntax reliably

[Yuan Fu]

> On Dec 23, 2023, at 2:17 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Stefan Monnier <monnier@iro.umontreal.ca>
>> Cc: dmitry@gutov.dev,  66732@debbugs.gnu.org,  dominik@honnef.co,
>>  casouri@gmail.com
>> Date: Wed, 20 Dec 2023 15:50:21 -0500
>> 
>>>> I think Dmitry is talking about the case where the faces were change
>>>> after the text was rendered (but before the end of the redisplay cycle).
>>>> 
>>>> I.e. the redisplay starts, renders up to position POS, then calls
>>>> jit-lock because `fonfitied` is nil, and jit-lock modifies faces of text
>>>> *before* POS.
>>> 
>>> This can only happen if a function called from jit-lock doesn't comply
>>> to the protocol wrt such changes, right?
>> 
>> I'm talking about a problem in the interaction between the redisplay
>> a jit-lock itself.
>> 
>> Jit-lock is aware of it and uses `jit-lock-force-redisplay` as needed to
>> account for it.
>> 
>>> Because otherwise the modified region would have been re-rendered on
>>> the next redisplay cycle at the latest.
>> 
>> Yes, if the jit-lock client (e.g. font-lock) follows the protocol, then
>> jit-lock should take care to re-render the regions when/where needed.
>> 
>> *Except* that the implementation of `jit-lock-force-redisplay` is
>> not effective and needs a change like the one suggested by Dmitry.
> 
> So can we install that change and close this bug, then?

I have a patch. Dmitry, WDYT?

Yuan

extend-region.patch
Description: Binary data