Problem with align-regexp with GNU/Emacs 29+

[Lele Gaifax]

Hi all,

today I faced a problem using `align-regexp' that I was not able to
solve.

Basically, I wanted to align a CSV set of rows, say a buffer containing
the following text

    1, 2, 3
    aa, bb, cc
    long string, shorter, a

using current (well, compiled around a week ago) Emacs master (with
native compilation).

Using `C-x h C-U M-x align-regexp RET ,\(\s-*\) RET RET RET y' didn't change 
the buffer at all. Since I do not use that facility often, I consulted
the related manual section, then the AlignCommands on the wiki, and
several other sources around the web, but could not figure out what I'm
doing wrong.

Then I installed version 28, and there the above worked as expected.

Back home, I retried with both version 30 (commit 750bc59c, 2023-02-18)
and version 29 (commit a5d4c29a, 2022-11-02), and the problem was
present as well. Then I installed Debian's Emacs 28.2, and the thing
worked.

Am I doing something wrong?

Thanks in advance for any hint,
bye, lele.
-- 
nickname: Lele Gaifax | Quando vivrò di quello che ho pensato ieri
real: Emanuele Gaifas | comincerò ad aver paura di chi mi copia.
lele@metapensiero.it  |                 -- Fortunato Depero, 1929.