bug#70617: 30.0.50; python-indent-shift-right indents left when line is whitespace

[Eli Zaretskii <eliz@gnu.org>]

> From: Patrick Poitras <patrick.f.poitras@gmail.com>
> Date: Sat, 27 Apr 2024 16:16:46 -0700
> 
> Hi all.
> 
> I've noticed this weird behavior of python-indent-shift-right.
> 
> Let's say I have a block of code. The "|" character represents my cursor
> 
> In a python file, I write
> 
> if True:
> |
> 
> (... file contents continue)
> 
> and then call python-indent-shift-right on an empty line. It does nothing. If the second line has any amount of
> spaces, the whitespace is entirely deleted. 
> 
> Given that Python's whitespace is syntactically significant, the expected behavior should be to add an indent
> to an empty line, or to prepend 4 characters (or 8, given user choice) to the empty line if it has whitespace.
> From a cursory glance, I think we're running into some behavior of indent-rigidly that tries to prevent the
> addition of superfluous white space following an indented block of code. I assume this would be potentially
> desirable for languages with non-significant whitespace, but in the case of the python-specific function, the
> resulting behavior defies both the function name and description.

Any comments?