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]

Eli Zaretskii <eliz@gnu.org> writes:

>> So, I'd like some way to configure `kill-whole-line'/`kill-line' to warn
>> user about killing hidden text when we detect that we are deleting a
>> folded heading. Something like:
>> 
>>    (y-or-n-p "Kill hidden subtree along with headline? ")
>> 
>> I believe that it might be useful in other situations as well. Like in
>> outline-mode or outline-minor-mode.
>
> How would kill-line know that it's about to kill a subtree?  All it
> knows is that it is killing some invisible text.

I imagine the following:

1. `kill-*-line' function will, by default, test if invisible text of
   length size is killed and query the user when called interactively.

2. Major modes could also set buffer-local `kill-line-query-function'
   that will return nil when killing should proceed without query or a
   string with query text.

-- 
Ihor Radchenko // yantar92,
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