bug#18796:

[Carlos Pita]

This fix seems to work:

In python-indent-region replace:

                (delete-horizontal-space)
                (indent-to (python-indent-calculate-indentation)))))

for

            (let ((indentation (python-indent-calculate-indentation)))
                  (delete-horizontal-space)
                  (indent-to indentation)))))

So the new indentation is calculated on the basis of the original one
(that is, before removing horizontal space).

On Wed, Oct 22, 2014 at 3:11 PM, Carlos Pita <carlosjosepita@gmail.com> wrote:
> I've doing some debugging. I found out why the bug happens, but I
> still have to think of a way to fix it:
>
> Say you are in a dedenter line like "else:". In python-indent-region
> delete-horizontal-space gets executed, so the dedenter "else:" moves
> to the first column and the current indentation becomes 0. Now
> python-info-dedenter-opening-block-position initializes indentation as
> the value returned by (current-indentation), that is 0. Then the
> opening block position is calculated and the following code gets
> executed:
>
>         (if (<= (current-indentation) indentation)
>             (setq position (car positions))
>           (setq positions (cdr positions)))))
>
> In this code (current-indentation) returns the indentation of the
> opening block, which is fine. But it gets compared to indentation,
> which is always 0. So the else branch is taken every time and
> positions is set to nil (cdr positions).
>
> Obviously the problem is that at the point
> python-info-dedenter-opening-block-position is called the original
> dedenter indentation was lost.
>
> Maybe the original indentation should be saved as a dynamic variable
> before deleting the horizontal space. Or the horizontal space
> shouldn't be deleted at all and indentation should happen as a
> displacement from the original position instead of a displacement from
> the left margin.