bug#17784: hilit-chg.el marks bigger change than necessary

bug#17784: hilit-chg.el marks bigger change than necessary

[Le Wang]

Repro steps:

1 create file:
<file>
hi
_
</file>

2. insert "a" on line 2, before "_"

3. backspace

4. insert "a" on line 2, before "_", again

5. inspect text property of "_", and notice it has hilit-chg property
even though it hasn't been changed.


-- 
Le

bug#17784: hilit-chg.el marks bigger change than necessary

[Stefan Monnier]

> 2. insert "a" on line 2, before "_"
> 3. backspace
> 4. insert "a" on line 2, before "_", again
> 5. inspect text property of "_", and notice it has hilit-chg property
> even though it hasn't been changed.

IIUC the property is added at step 3 to remember that something was
removed here.  So I guess what you're saying is that we could remove
that property at step 4 since the insertion makes it redundant.


        Stefan

bug#17784: hilit-chg.el marks bigger change than necessary

[Le Wang]

[-- Attachment #1: Type: text/plain, Size: 547 bytes --]

Yes that sounds right.
On 16 Jun 2014 17:02, "Stefan Monnier" <monnier@iro.umontreal.ca> wrote:

> > 2. insert "a" on line 2, before "_"
> > 3. backspace
> > 4. insert "a" on line 2, before "_", again
> > 5. inspect text property of "_", and notice it has hilit-chg property
> > even though it hasn't been changed.
>
> IIUC the property is added at step 3 to remember that something was
> removed here.  So I guess what you're saying is that we could remove
> that property at step 4 since the insertion makes it redundant.
>
>
>         Stefan
>

[-- Attachment #2: Type: text/html, Size: 913 bytes --]

bug#17784: hilit-chg.el marks bigger change than necessary

[Lars Ingebrigtsen]

Le Wang <l26wang@gmail.com> writes:

> Repro steps:
>
> 1 create file:
> <file>
> hi
> _
> </file>
>
> 2. insert "a" on line 2, before "_"
>
> 3. backspace
>
> 4. insert "a" on line 2, before "_", again
>
> 5. inspect text property of "_", and notice it has hilit-chg property
> even though it hasn't been changed.

This should now be fixed in Emacs 28.  The problem was that the code
tried to cater for the case where you have

hi
_

and then

hi
ab_

then deleting the "a" and then inserting something else.  That worked
for "b" (which was already highlighted), but not for "_", which was
not.  So I introduced a new text property to separate the two cases.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no