Subject: bug#16818: Acknowledgement (Undo in region after markers in undo history relocated)

From: Stefan Monnier <[email-masked]>
Date: Thu, 13 Mar 2014 09:24:28 -0400

>> Thinking more about this, I think this is fixing the symptom, but
>> not the cause. The cause is that primitive-undo shouldn't blindly
>> obey a (MARKER . OFFSET) entry. Instead it should only obey it if
>> the marker still points at the corresponding place.

> From what I can tell, the root cause is relocating markers to
> unrelated locations in the buffer while another part of Emacs still
> has a reference to it.

Not sure in which way what you're saying is different from what I'm saying.
Are we in violent agreement?

> Your counter proposal is a step from the root.  For instance, the
> markers within the mark rings will not adjust correctly, whilst with
> my patch they will.

Can you give an example incorrect adjustment?

>> (creating new markers each time instead)
> My patch actually results in fewer markers created.

Right, I didn't mean that creating new markers is a problem.

        Stefan