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From: Stefan Monnier <monnier@iro.umontreal.ca>
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Subject: Re: Edebug corrupting point in buffers.
Date: Thu, 03 Nov 2022 16:35:09 -0400
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Xref: news.gmane.io gmane.emacs.devel:299103
Archived-At: <http://permalink.gmane.org/gmane.emacs.devel/299103>

>> I wish Someone=E2=84=A2 could dig into the problem further and find the =
source
>> of the problem and an actual fix, but indeed, this seems like a fair
>> workaround in the mean time.
>
> I think I said something about this earlier on in the thread.  The cause
> seems to be that random bits of software wrongly consider it their
> business to overwrite the buffer point with a window point.
>
> Amongst these bits of software are select-window,
> set-window-configuration, and our very own edebug-set-buffer-points
> (triggered by the option edebug-save-displayed-buffer-points).  I think
> there are many more.

This characterization is a bit too vague and open-ended to be
actionable, sadly.  I was thinking of "the source of the problem" for
the specific case you described earlier in the bug-report (i.e. one we
can conveniently reproduce).  Admittedly, fixing this one case may
not fix all cases, but will at least get us closer.

>> Maybe a good short term "fix/workaround" is to change the implementation
>> of `edebug-save-windows` so that in addition to the windows's info it
>> also saves&restores the buffer-point of those buffers displayed in the
>> saved windows.
> My first patch did something like this.  It saved the buffer points of
> all buffers, then restored it in buffers selected by the user.  This
> patch was rejected (and I think rightly so) for being too clumsy to use.

I was thinking that by limiting the saved&restored buffer-points to
those displayed in the saved windows, we'd make it more "automatic" than
your patch.


        Stefan