Subject: Re: bug#27634: 25.2.1; C-g does not quit register-read-with-preview

From: Tino Calancha <[email-masked]>
Date: Mon, 10 Jul 2017 15:33:42 +0900

Paul Rankin <[email-masked]> writes:

> When saving to a register C-g does not quit but instead saves to the register "C-g".
>
> To reproduce:
>
> 1. $ emacs -Q
> 2. M-x point-to-register [C-x r SPC]
> 3. C-g
>
> Expected results:
>
> C-g should call keyboard-quit and escape point-to-register
>
> Actual results:
>
> Point marker is saved to register "C-g".

> I have worked around this with the following patch to register.el.gz:
>
> @@ -164,7 +164,7 @@
>  		       help-chars)
>  	    (unless (get-buffer-window buffer)
>  	      (register-preview buffer 'show-empty)))
> -	  (if (characterp last-input-event) last-input-event
> +	  (if (< 31 last-input-event 127) last-input-event
>  	    (error "Non-character input-event")))
>        (and (timerp timer) (cancel-timer timer))
>        (let ((w (get-buffer-window buffer)))
>
> However, I think this will not work on international keyboards and so is probably a poor fix.
How about the following?

@@ -164,6 +164,8 @@ register-read-with-preview
 		       help-chars)
 	    (unless (get-buffer-window buffer)
 	      (register-preview buffer 'show-empty)))
+          (when (eq (string-to-char "\C-g") last-input-event)
+            (keyboard-quit))
 	  (if (characterp last-input-event) last-input-event
 	    (error "Non-character input-event")))
       (and (timerp timer) (cancel-timer timer))

--8<-----------------------------cut here---------------start------------->8---
commit 51de600be1351704d4e435a4977d63b3d4e04eaf
Author: Tino Calancha <[email-masked]>
Date:   Mon Jul 10 15:22:32 2017 +0900

    Don't set registers in 'C-g'
    
    That key is reserved to abort commands (Bug#27634).
    * lisp/register-tests.el (register-read-with-preview):
    Abort when user inputs 'C-g'.
    * test/lisp/register-tests.el (register-test-bug27634): Add test.

diff --git a/lisp/register.el b/lisp/register.el
index 7cc3ccd870..19b7dee4b9 100644
--- a/lisp/register.el
+++ b/lisp/register.el
@@ -164,6 +164,8 @@ register-read-with-preview
 		       help-chars)
 	    (unless (get-buffer-window buffer)
 	      (register-preview buffer 'show-empty)))
+          (when (eq (string-to-char "\C-g") last-input-event)
+            (keyboard-quit))
 	  (if (characterp last-input-event) last-input-event
 	    (error "Non-character input-event")))
       (and (timerp timer) (cancel-timer timer))
diff --git a/test/lisp/register-tests.el b/test/lisp/register-tests.el
new file mode 100644
index 0000000000..30c1468e25
--- /dev/null
+++ b/test/lisp/register-tests.el
@@ -0,0 +1,40 @@
+;;; register-tests.el --- tests for electric.el
+
+;; Copyright (C) 2017 Free Software Foundation, Inc.
+
+;; Author: Tino Calacha <[email-masked]>
+;; Keywords:
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+
+;;; Code:
+(require 'ert)
+(require 'cl-lib)
+
+(ert-deftest register-test-bug27634 ()
+  "Test for http://debbugs.gnu.org/27634 ."
+  (cl-letf (((symbol-function 'read-key) #'ignore)
+            (last-input-event 7)
+            (register-alist nil))
+    (should (equal 'quit
+                   (condition-case err
+                       (call-interactively 'point-to-register)
+                     (quit (car err)))))
+    (should-not register-alist)))
+
+(provide 'register-tests)
+;;; register-tests.el ends here

--8<-----------------------------cut here---------------end--------------->8---
In GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2017-07-10
Repository revision: 273f4bde39af5d87f10fd58f35b666dfa8a996a3