Subject: Re: bug#79200: 31.0.50; Duplicated elements for '#<marker at' in buffer-undo-list

From: Óscar Fuentes Óscar Fuentes <[email-masked]>
Date: Sat, 09 Aug 2025 13:37:51 +0200

Eli Zaretskii <[email-masked]> writes:

>> > But I can only reproduce this on the igc branch.  On master, I see a
>> > single entry for marker adjustment, not many identical ones.
>> 
>> On master you need more elaborate sequences of typing, undoing and
>> redoing, but it is definitively reproducible.
>
> Why does one need more elaborate sequences on master?

I don't know why. I mentioned the lack of compaction in igc as a
possible factor.

>> Maybe it is easier on igc because it does not do compactation, as Pip
>> noted.
>
> If compacting the undo-list solves the issue on master, I don't see
> this as a grave problem on master.

The copious sequences of #marker elements happen on master too (the
contents of `buffer-undo-list` that I copied on the previous messages
are from master.) I don't know if they end inundating buffer-undo-list
to the point of losing undo info like they do in igc, though, but looks
like a bug to me even if there are no user-observable effects. Those
sequences use memory and require cpu time, for sure.

>> Also tried your suggestion of calling garbage-collect (on master) before
>> looking at buffer-undo-list. The sequences of duplicated elements
>> remained.
>
> On the master branch or on the igc branch?

On master, as mentioned.