bug#39680: closed (27.0.60; electric-pair-mode broken by undo)

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Your message dated Thu, 12 Mar 2020 10:04:11 -0400
with message-id <address@hidden>
and subject line Re: bug#39680: 27.0.60; electric-pair-mode broken by undo
has caused the debbugs.gnu.org bug report #39680,
regarding 27.0.60; electric-pair-mode broken by undo
to be marked as done.

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39680: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=39680
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> --- Begin Message ---
>
>
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> Subject: 
>
> 27.0.60; electric-pair-mode broken by undo
>
>
>
>
> Date: 
>
> Wed, 19 Feb 2020 19:34:37 +0100
>
>
>
>
> Hello,
>
> Commit e66d5a1c45 (2019-02-19T00:00:44Z!address@hidden) might
> have introduced a bug.  From emacs -Q:
>
> 1. C-x b foo RET
> 2. M-x electric-pair-mode RET
> 3. (
>     - A closing parenthesis has been inserted.
> 4. C-b C-f
>     - This is to break undo grouping.
> 5. a
> 6. C-_
> 7. (
>
> In Emacs 26.3, buffer foo contains "(())" and point is after the
> innermost opening bracket.
>
> In Emacs 27, buffer foo contains "()" and point is after the closing
> bracket.  The *Messages* buffer shows:
>
> > cancel-change-group: Undoing to some unrelated state
>
> NB: this can be reproduced with other electric-pair characters, e.g. ".
> I found the bug in a Python buffer trying to write a tuple of strings: I
> opened a parenthesis, forgot to add quotes, wrote a string, hit undo,
> tried to insert a single quote… and got moved past the end parenthesis
> instead.
>
> I tried to write a non-regression test; unfortunately what I came up
> with does not catch this bug reliably:
>
> (ert-deftest electric-pair-undo-unrelated-state ()
>   (with-temp-buffer
>     (buffer-enable-undo)
>     (electric-pair-mode)
>     (let ((last-command-event ?\())
>       (self-insert-command 1))
>     (undo-boundary)
>     (insert "hi there")
>     (undo)
>     (let ((last-command-event ?\())
>       (self-insert-command 1))))
>
> C-x C-e'ing the (with-temp-buffer …) form only triggers the error once
> every two evaluations, for some reason.
>
>
> Thank you for your time.
>
>
> In GNU Emacs 28.0.50 (build 5, x86_64-pc-linux-gnu, GTK+ Version 3.24.13, cairo 
> version 1.16.0)
>  of 2020-02-19 built on my-little-tumbleweed
> Repository revision: e1e1bd8f85c53fea9f61b6ec99b461ddd93461b9
> Repository branch: master
> Windowing system distributor 'The X.Org Foundation', version 11.0.12007000
> System Description: openSUSE Tumbleweed
>
> Configured using:
>  'configure --with-xwidgets --with-cairo'
>
>
>
> --- End Message ---
> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#39680: 27.0.60; electric-pair-mode broken by undo
>
>
>
>
> Date: 
>
> Thu, 12 Mar 2020 10:04:11 -0400
>
>
>
>
> User-agent: 
>
> Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux)
>
>
>
>
> >> Eli, is the patch below OK for `emacs-27`?
> > Yes, thanks.
>
> Thanks, installed,
>
>
>         Stefan
>
>
>
> --- End Message ---