Subject: bug#35191: 27.0.50; Error signaled by undo--wrap-and-run-primitive-undo

From: Noam Postavsky <[email-masked]>
Date: Tue, 09 Apr 2019 20:41:52 -0400

retitle 35191 27.0.50; undo of comment-region signals error (when comment-combine-change-calls=t)
tags 35191 + confirmed
quit

Stefan Monnier <[email-masked]> writes:

> Save the file below and then open it as follows:

It's enough to use a single line

    foo ;; bar

in emacs-lisp-mode.  And the problem only happens with
comment-combine-change-calls set to t (the default).

>     % emacs -Q ..../zones.el
>     C-M-f C-M-b                   ;; Move before first form
>     C-M-SPC M-;                   ;; Comment out first form
>     C-x u                         ;; Undo last change
>
> When I do that, I see an error message in the echo area that says:
>
>     Changes to be undone by function different than announced