bug#62717: 29.0.60; c-ts-mode does not indent the first line in a function after RET

[Dmitry Gutov]

On 09/04/2023 08:19, Eli Zaretskii wrote:
> > Cc: Theodor Thornhill<theo@thornhill.no>, Yuan Fu<casouri@gmail.com>,
> >   62717@debbugs.gnu.org,
> >   João Távora<joaotavora@gmail.com>,
> >   Alan Mackenzie<acm@muc.de>
> > Date: Sun, 9 Apr 2023 03:20:23 +0300
> > From: Dmitry Gutov<dmitry@gutov.dev>
> >
> > What does this mean for us? Short of reimplementing nvim-treesitter's
> > algorithm (and I haven't read Atom's or Zed's indentation code;
> > anybody's welcome to chime in with a summary of either), we could just
> > install the patch at the end of this message: it fixes this particular
> > case, in a bit hackish way, but at least it doesn't affect other languages.
> >
> > Note that it still doesn't fix very similar cases, e.g.
> >
> >     int main () {
> >       for (;;) {<RET>
> >
> > (we need additional rules looking for ERROR nodes, like in nvim's
> > indent.scm), but in does fix
> >
> >     int main () {
> >       for (;;) {}<RET>
> >
> > and
> >
> >     int main () {
> >       int foo;<RET>
> >
> > I'm not sure, though, what is the big deal with adding the top-level
> > function's closing curly first thing before writing the body (after that
> > the parser starts working much better), so as far as I'm concerned this
> > patch is very optional. It does add some complexity, after all.
> If the patch solves some of the problems, passes the test suite, and
> doesn't introduce any regressions you see, I think you should install
> it (unless someone here objects).

With this kind of change, it's hard to judge regression potential in 
advance. I don't really write C/C++ myself with any regularity. And our 
test suite doesn't really work incomplete parse trees, I think.

So if we want this in emacs-29, I think someone interested should try 
running with this patch applied, at least for a little bit. Maybe just 
wait for a couple of days, if Daniel is testing it already.