Re: Edebug corrupting point in buffers.

[Stefan Monnier <monnier@iro.umontreal.ca>]

Eli Zaretskii [2022-11-02 16:00:52] wrote:

>> Date: Wed, 2 Nov 2022 11:34:37 +0000
>> Cc: emacs-devel@gnu.org
>> From: Alan Mackenzie <acm@muc.de>
>> 
>> (i) Emacs -Q.
>> (ii) On a single frame, arrange buffers *scratch*, test-edebug.el, and
>>   some other substantial buffer, that I call emacs.README.
>> (iii) Put point in emacs.README somewhere other than point-max.
>> (iv) Instrument test-edebug for edebug with C-u C-M-x.
>> (iv)a Put point into window *scratch*.
>> (v) M-: (test-edebug).
>> (vi) Step through test-edebug using the space key.
>> (vii) Note that the second text insertion happens where point was in the
>>   window, not at point-max.  This is the bug.
>
> Yes, I see the problem, but setting edebug-save-windows to nil
> eliminates it.  So I think we already have a solution for the rare
> situations where this is an issue.

I wish Someone™ 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.

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.


        Stefan