bug#72750: 29.3; indent-region changes semantics of python code

[Michael Arndt via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Hi,

I have a problem when indenting python files. There seems to be a case
when using indent-region changes the semantics of the python code. When
there is no blank line after an if-statement, the next line becomes part
of the if statement.

The problem can be reproduced by the following steps:

1. Start emacs -Q
2. Create a python file with the following contents:

if False:
      print("output1")
print("output2")

3. Use M-x mark-whole-buffer
4. Use M-x indent-region
5. The file contents change into:

if False:
      print("output1")
      print("output2")

The problem can be avoided by adding a blank line after the if statement.
Because I use a custom indentation function that calls (indent-region
(point-min) (point-max)) this can happen pretty quickly. Is this a
limitation of python-indent-region?

Greetings
Michael


In GNU Emacs 29.3 (build 1, x86_64-pc-linux-gnu, GTK+ Version 2.24.33,
cairo version 1.18.0) of 2024-04-02 built on titan
Repository revision: ae8f815613c2e072e92aa8fe7b4bcf2fdabc7408
Repository branch: HEAD
Windowing system distributor 'The X.Org Foundation', version 11.0.12101011
System Description: Debian GNU/Linux trixie/sid

Configured using:
'configure CFLAGS=-O3 --with-json --with-native-compilation
--without-xinput2 --with-modules --prefix=/usr/local
--with-tree-sitter'

Configured features:
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LIBSELINUX LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG
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XIM XPM GTK2 ZLIB

Important settings:
value of $LC_TIME: de_DE.UTF-8
value of $LANG: en_US.UTF-8
locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
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eldoc-mode: t
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electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-mode: t
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file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
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line-number-mode: t
indent-tabs-mode: t
transient-mark-mode: t
auto-composition-mode: t
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Load-path shadows:
None found.

Features:
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Memory information:
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