Subject: 29.4; hideshow: hs-hide-level hides multiple top-level blocks as one
From: Christoph Groth <[email-masked]>
To: [email-masked]
Date: Sun, 05 Jan 2025 19:53:04 +0100
List-Id: <debbugs-submit.debbugs.gnu.org>

Hello,

I noticed the following problem when using a homemade function that
allows me to cycle hideshow visibility in a way similar to org-mode.
The issue, however, is independent of any customization (it appears with
emacs -Q as well).

I can reproduce the issue with the following source file

https://gitlab.kwant-project.org/kwant/kwant/-/raw/0d679b3efecd145d13e3174c60d829a7c3cd4374/kwant/builder.py

I tried simplifying that file to isolate the issue, but did not arrive at
something more useful than the original.  To demonstrate the issue:

(1) Download the above file.
(2) Open it with emacs -Q builder.py.  Point is not moved.
(3) M-x hs-minor-mode RET
(4) M-x hs-hide-level RET

The result is that the buffer shows only two hidden blocks, with the
buffer ending in

@total_ordering
class SiteFamily(metaclass=abc.ABCMeta):...

This is incorrect, since there are many other classes and top-level
functions in the file.  Each should appear as a separate top-level
block.

If M-x hs-hide-all is run instead of step (4) the hiding works as
expected, many more top-level hidden blocks appear.  M-x hd-hide-level
also produces the expected effect if the second block created by (4) is
un-hidden in some way.  For example if the following two steps are added
to the above sequence:

(5) M-x hs-show-all RET
(6) M-x hs-hide-level RET

I would expect that hs-hide-level always produces the same result when
called with point at the same position in a buffer.

I hope that this somewhat obscure observation allows to fix some
inconsistency.

Thanks,
Christoph

---

In GNU Emacs 29.4 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.38,
 cairo version 1.16.0) of 2024-12-15, modified by Debian built on sbuild
Windowing system distributor 'The X.Org Foundation', version 11.0.12101007
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