bug#65734: [BUG] kill-whole-line on folded subtrees [9.6.8 (release_9.6.8-3-g21171d @ /home/w/usr/emacs/0/29/0/lisp/org/)]

[Ihor Radchenko <yantar92@posteo.net>]

Eli Zaretskii <eliz@gnu.org> writes:

>> >> In addition, `org-kill-line' acts specially in certain scenarios:
>> >> 
>> >> For
>> >> * Heading <point> text :tag1:tag2:
>> >> 
>> >> `org-kill-line' will keep and re-align ":tag1:tag2:":
>> >> 
>> >> * Heading <point>      :tag1:tag2:
>> >> 
>> >> It would be nice if we could express such behavior without overriding
>> >> the `kill-line' command.
>> ...
>> I am not sure if I like the idea of text property - marking all the tags
>> in buffer with text property is expensive.
>
> Then perhaps just a special value for buffer-invisibility-spec, or
> some other simple variation of a property Org already uses?

We may have a misunderstanding here.
In "* Heading text :tag1:tag2:", everything is visible yet Org needs to
protect ":tag1:tag2: from being killed by `kill-line', but not from
`kill-whole-line'. Moreover, the behaviour also depends on the point
position - if point is inside ":tag1:tag2:", we fall back to the default
behaviour. And the whole "special" behaviour can also be switched off by
flipping `org-special-ctrl-k'.

Invisibility has nothing to do with this need.

>> What about something like `end-of-visible-line-function'?
>
> That is also a possibility, but it will then affect kill-line
> _anywhere_ in the buffer, whereas a text property can have a more
> localized effect.  Are you sure kill-line will need this customization
> on the whole buffer?

Applying text property is not free - (1) we need to do it across the
whole buffer, which scales poorly; (2) we need to keep it updated as the
buffer changes, which scales even worse. In addition, adding more text
properties slow down redisplay, which Org already strains to its limits.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
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