bug#35286: 26.2; indent-sexp broken

[Noam Postavsky <npostavs@gmail.com>]

Leo Liu <sdl.web@gmail.com> writes:

> On 2019-04-15 19:57 -0400, Noam Postavsky wrote:
>> I put that code there because Emacs 25 and earlier also indents more
>> than one sexps after point in some cases.
>
> I didn't know that. Are those cases obscure?

The minimal example would be (with point before "foo", the "xx)"
part gets indented too):

foo (bar
 xx)

I'm not sure if anyone relies on that (I broke it in 26.1 and nobody
reported it).  The main motivating example is

#s(foo
bar)

which is due to forward-sexp not handling #s correctly for Emacs Lisp
(it's treated as a separate sexp rather than as a whole record
expression).

>> The regression is that the Emacs 26 code gets confused by comments at
>> the end of line. Here's a patch for emacs-26 to fix this:
>
> Not just comments though it can be anything. For example, put the
> following in prolog-mode. Move point to the first `{' char and then M-x
> indent-sexp.

Hmm, I'm a bit confused here.  I thought indent-sexp is only good for
Lisp-based languages.  Do lisp-indent-calc-next/calculate-lisp-indent
give usable results for prolog or ruby??