bug#62333: 30.0.50; Issue with tree-sitter syntax tree during certain changes

[Dmitry Gutov]

On 29/03/2023 14:08, Eli Zaretskii wrote:
> > Date: Wed, 29 Mar 2023 00:08:53 +0300
> > Cc: wkirschbaum@gmail.com, gregory@heytings.org, casouri@gmail.com,
> >   62333@debbugs.gnu.org
> > From: Dmitry Gutov <dgutov@yandex.ru>
> >
> > > > Is that because we don't think the user level narrowing is done purely
> > > > for visual effect?
> > >
> > > Indeed, it isn't always for visual effect.
> >
> > When isn't it? Is there a way to determine that from code?
>
> I'm not sure I understand the question, but if I do, then narrowing to
> prevent search functions

If we're talking about isearch, then that seems like a natural 
consequence of visual effect (hiding the remainder of the buffer): even 
if isearch highlighted those other hits, they would not be visible.

> and commands from finding irrelevant hits is
> one example that comes to mind.

More or less the same, except we have the user option 
widen-automatically, which apparently (?) allows any command to "widen 
when they want to"?

Used by popular demand in e.g. xref--goto-char. And IIUC 'find-tag' just 
always calls 'widen' irrespective of this variable's value.

> > > > judging by regular user requests for make this or that command
> > > > ignore user-level narrowing, it seems like "purely visual" should be the
> > > > default interpretation.
> > >
> > > I think you base your judgment on feedback from users who are not used
> > > to take advantage of narrowing in editing.  I think most young people
> > > aren't, since this feature is more-or-less unique to Emacs.
> >
> > Either narrowing should be used to change lexical/grammatical/etc
> > context, or it should not. Do we have any documentation that says one or
> > the other way? That should affect how Lisp code deals with narrowing --
> > which interactive functions should widen, and so on.
>
> I was talking about user commands that narrow, so I'm not sure I
> understand how documentation could help.  When the user types "C-x n n",
> there's nothing Emacs can do except obey.

There is really only one main user command that narrows, and that's 
narrow-to-region, bound to 'C-x n n'.

But none of that describes how other Emacs features should react to it.

Simple example: if the beginning of the narrowed region falls inside a 
(let's say multine) string, should the visible remainder of that string 
continue to be highlighted as a string? Or should the buffer contents 
after the string's closer now be highlighted as being inside a string?