Subject: bug#24992: 25.1; Using mouse, can put empty keyboard macro in macro ring

From: Gemini Lasswell <[email-masked]>
Date: Tue, 22 Nov 2016 14:32:18 -0800

The commentary in lisp/kmacro.el says "Note: an empty macro is never
added to the macro ring.", but here is a way to add an empty macro to
the ring using kmacro-end-call-mouse, which is by default bound to
S-mouse-3. I am not aware of any serious side effects of there being an
empty macro in the ring.

To reproduce, with emacs -Q and the mouse pointer positioned over your
Emacs window:

C-x ( aaa S-mouse-3
C-x ( S-mouse-3
C-x ( bbb S-mouse-3
C-x C-k C-n C-n C-n

This defines three macros, one which inserts "aaa", an empty one, and one
which inserts "bbb". Then the repeated C-n's of the last step cycle
through the macros in the ring and display them in the echo area.

I'm attaching a patch which makes kmacro-end-call-mouse do the same
thing that kmacro-end-and-call-macro does in this case, which is to end
the definition of the empty macro, pop the empty macro off the ring, and
then run the macro which becomes current.

>From 2e5a84b47b72519aabe8e4aa392e2b53858aa8cf Mon Sep 17 00:00:00 2001
From: gazally <[email-masked]>
Date: Sun, 20 Nov 2016 14:24:51 -0800
Subject: [PATCH] Don't add empty keyboard macro to macro ring

* lisp/kmacro.el (kmacro-end-call-mouse): Don't save a newly defined
macro if it is empty.
---
 lisp/kmacro.el | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lisp/kmacro.el b/lisp/kmacro.el
index 2e743b4..49787f5 100644
--- a/lisp/kmacro.el
+++ b/lisp/kmacro.el
@@ -744,7 +744,13 @@ kmacro-end-call-mouse
 If kbd macro currently being defined end it before activating it."
   (interactive "e")
   (when defining-kbd-macro
-    (end-kbd-macro))
+    (end-kbd-macro)
+    (when (and last-kbd-macro (= (length last-kbd-macro) 0))
+      (setq last-kbd-macro nil)
+      (message "Ignore empty macro")
+      ;; Don't call `kmacro-ring-empty-p' to avoid its messages.
+      (while (and (null last-kbd-macro) kmacro-ring)
+        (kmacro-pop-ring1))))
   (mouse-set-point event)
   (kmacro-call-macro nil t))
 
-- 
2.10.1

 GNU Emacs 25.1.1 (x86_64-apple-darwin15.6.0, NS appkit-1404.47 Version 10.11.6 (Build 15G1004))
 of 2016-10-09 built on rainbow.local
Windowing system distributor 'Apple', version 10.3.1404
Configured using:
 'configure --disable-dependency-tracking --disable-silent-rules
 --enable-locallisppath=/usr/local/share/emacs/site-lisp
 --infodir=/usr/local/Cellar/emacs/25.1/share/info/emacs
 --prefix=/usr/local/Cellar/emacs/25.1 --without-x --with-xml2
 --without-dbus --with-gnutls --with-imagemagick --with-rsvg --with-ns
 --disable-ns-self-contained'

Configured features:
JPEG RSVG IMAGEMAGICK NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS
NS

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Defining kbd macro...
Keyboard macro defined
Defining kbd macro...
Keyboard macro defined
Macro: aaa
Macro:
Macro: bbb
Macro: aaa
Macro:
Macro: bbb

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns mail-prsvr mail-utils cl-seq
cl-extra help-mode easymenu edmacro cl-loaddefs pcase cl-lib kmacro
time-date mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel ns-win ucs-normalize term/common-win tool-bar dnd
fontset image regexp-opt fringe tabulated-list newcomment elisp-mode
lisp-mode prog-mode register page menu-bar rfn-eshadow timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame
cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai
tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese charscript
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote kqueue cocoa ns
multi-tty make-network-process emacs)

Memory information:
((conses 16 197854 6343)
 (symbols 48 19937 0)
 (miscs 40 49 173)
 (strings 32 15610 5377)
 (string-bytes 1 449702)
 (vectors 16 33190)
 (vector-slots 8 656305 5396)
 (floats 8 159 206)
 (intervals 56 215 0)
 (buffers 976 17))