bug#56197: 28.1; lisp-fill-paragraph result regressed with Emacs 28

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hello,

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Maxim Cournoyer <maxim.cournoyer@gmail.com> writes:
>
>> ;; Emacs 28
>>     (description "IBus-Anthy is an engine for the input bus \"IBus\").  It adds the Anthy
>> Japanese language input method to IBus.  Because most graphical applications
>> allow text input via IBus, installing this package will enable Japanese
>> language input in most graphical applications.")
>
> [...]
>
>> Simply commenting out the newly added block, evaluating the defun and
>> running it on my example reverts to the previous correct behavior.
>
> I'm not sure the previous behaviour was any more correct.  It's now
> filling that string as if it, well, is a string, so that if you insert
> it somewhere, the lines have similar lengths.  The previous behaviour
> was to fill "what you see in the buffer", which is wrong in most
> contexts.
>
> So I don't know.  Anybody have an opinion?

Apologies if my previous example lacked too much context and confused
more than helped.  Here's another example, where I just experienced the
problem after revamping the GNU Guix 'font-abattis-cantarrel' package
definition:

--8<---------------cut here---------------start------------->8---
(define-public font-abattis-cantarell
  (package
    (name "font-abattis-cantarell")
    (version "0.303")
    (source
     (origin
       (method git-fetch)
       (uri (git-reference
             (url "https://gitlab.gnome.org/GNOME/cantarell-fonts")
             (commit (string-append "v" version))))
       (file-name (git-file-name name version))
       (sha256
        (base32
         "1d1ay0fdqchk0wa5yqxis2c98imvzsbbd2kjv0x8sk4fm419847b"))))
    (build-system meson-build-system)
    (arguments
     (list #:configure-flags #~(list "-Dbuildstatics=true")))
    (native-inputs
     (list gettext-minimal
           psautohint
           python
           python-cffsubr
           python-fontmath
           python-statmake
           python-ufo2ft))
    (home-page "https://wiki.gnome.org/Projects/CantarellFonts")
    (synopsis "Cantarell sans-serif typeface")
    (description "The Cantarell font family is a contemporary Humanist sans-serif designed for
on-screen reading.  It is used by GNOME@tie{}3.  This package contains both
the non-variable as well as the variable versions of the font.")
    (license license:silofl1.1)))
--8<---------------cut here---------------end--------------->8---
    
This is a Scheme sexp extracted from the (gnu packages fonts) Guile
module.  Hitting `lisp-fill-paragraph' (M-q) causes the above
indentation, where the first line of the description extends past the
`fill-column' value.

I hope that helps,

Thanks!

Maxim