bug#17658: Python mode has odd indentation behavior

["Andreas Röhler" <andreas.roehler@easy-emacs.de>]

On 02.06.2014 15:36, Stefan Monnier wrote:
>>> Makes no difference,
>> Did you try it?
>
> I tried it in Emacs-24.3 which doesn't enable electric-indent-mode by
> default, but suffers from the same problem.  Admittedly, In 24.4,
> I half-fixed the problem by linking this python-mode feature to
> electric-indent-mode, so that it can be turned off.
>
>> The chars, which trigger an indent, may differ. In this case a comma
>> triggers it.
>
> Any char triggers it.  As I said:
>
>     The important detail is not to hit "," but to insert a char right
>     before the inner close paren.
>
> The comma is not in electric-indent-chars.
>
> Here's the offending code in python-indent-post-self-insert-function:
>
>       ((and (not (bolp))
>             (memq (char-after) '(?\) ?\] ?\})))
>        (save-excursion
>          (goto-char (line-beginning-position))
>          ;; If after going to the beginning of line the point
>          ;; is still inside a paren it's ok to do the trick
>          (when (python-syntax-context 'paren)
>            (let ((indentation (python-indent-calculate-indentation)))
>              (when (< (current-indentation) indentation)
>                (indent-line-to indentation))))))
>
> This means that current line is reindented whenever you insert a char
> right before a close-paren and line-beginning-position is inside some
> parentheses.  Since reindenting a line is problematic in Python, it
> should only be done when we really know for sure that the current indent
> is wrong.  So clearly the above condition triggers too often.
> But I don't understand the intention of the code, i.e. I don't
> understand when the above is meant to trigger reindentation, so I don't
> know how to fix it.  Presumably Fabián should be able to shed some
> light here.
>
>
>
>          Stefan
>

Agree, thanks a lot for the details!

Andreas