bug#60692: 29.0.60; current-indentation wrong without outline ellipsis

[Juri Linkov]

forcemerge 56837 60692
thanks

> About current-indentation: it skips invisible text, so it's unclear to
> me why you expected to see 2.  The doc string says:
>
>   Text that has an invisible property is considered as having width 0, unless
>   `buffer-invisibility-spec' specifies that it is replaced by an ellipsis.
>
> The "current indentation" on the line of buffer position 8 is entirely
> in invisible text, and current-indentation only accounts for _visible_
> whitespace, per the above documentation.

Thanks for the reference, it explains the problem.
But this is a very strange logic.  I don't get it.
Why it depends on the presence of the ellipsis
and fails without it?

Now I see this bug report is a duplicate of bug#56837.
This is a problem because modes use 'current-indentation'
to get an outline level in 'outline-level' function, e.g.

  (setq-local outline-level
              (lambda ()
                "`outline-level' function for Python mode."
                (1+ (/ (current-indentation) python-indent-offset))))

  (setq-local outline-level (lambda () (1+ (/ (current-indentation)
                                         ruby-indent-level))))

But this fails when users want to remove an ellipsis.