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

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]

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'

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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
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Major mode: Lisp Interaction

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Load-path shadows:
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Memory information:
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bug#72750: 29.3; indent-region changes semantics of python code

[Andreas Röhler]

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Am 21.08.24 um 20:06 schrieb Michael Arndt via Bug reports for GNU 
Emacs, the Swiss army knife of text editors:
> 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
>
>
Hi Michael,

I'm not maintaining the related code, just a comment:

as indent might by syntax at Python, there is not way for 
auto-formatting - unless you are happy with the outmost reasonable indent.

|Best,|

|Andreas
|

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