bug#21211: closed (24.4; Possible regression in xterm mouse handling wit

I think I'm seeing a slight regression in the behavior of the mouse wheel with xterm-mouse-mode. This is when running in -nw mode, using Windows PuTTY as a client, with ssh into a linux box where the emacs runs. I've verified that it's nothing in my init.el or site-lisp files. I've verified that the bad behavior described below does not happen when running on the same host with a real xterm.

The problem seems to have begun with emacs 24.4. I verified with fresh builds from source that it works with 24.3, but not with 24.4 or 24.5.

The problem:

When I scroll using the mouse wheel, the buffer scrolls as before, but there's also a screen flash, and a complaint in the mini buffer: "M-[ m" is undefined". It seems that emacs is seeing this escape sequence after each movement of the mouse wheel. I have PuTTY set to report xterm mouse events, and I have xterm-mouse-mode turned on in emacs.

I can work around this by adding a global-set-key to recognize the escape sequence and ignore it. As yet, I don't know if my workaround breaks anything else. The escape sequence means "Turn off all special character attributes, e.g., blinking, bold, etc.". Here's the workaround I'm using:

(global-set-key (kbd "\e [ m") (lambda () (interactive) nil))

Here is the lossage output under various combinations of emacs version and client. I notice that with 24.4 the character \230 is displayed differently than in 24.3, don't know if that relates to the problem. These are all started as emacs -q -nw. After emacs starts up, I enable xterm-mouse-mode, and then do a single scroll down with the mouse wheel:

This is emacs 24.3 with the PuTTY client. The bad behavior is not seen in this case.

ESC [ > 0 ; 1 3 6 ; 0 c ESC x x t e r m - m o u s e

- m o d e RET ESC [ M a \230 % ESC [ M # \230 % C-h

This is emacs 24.3 with the genuine xterm client. The bad behavior is not seen in this case.

ESC [ > 0 ; 2 7 8 ; 0 c ESC ] 1 1 ; r g b : 0 0 0 0

/ 0 0 0 0 / 0 0 0 0 ESC \ ESC x x t e r m - m o u s

e - m o d e RET ESC [ < 6 5 ; 5 0 ; 1 3 M C-h l

This is emacs 24.4 with the PuTTY client. The bad behavior is seen in this case.

ESC [ > 0 ; 1 3 6 ; 0 c ESC x x t e r m - m o u s e

- m o d e RET ESC [ M a Â K ESC [ M # Â K C-h

This is emacs 24.4 with the genuine xterm client. The bad behavior is not seen in this case.

ESC [ > 0 ; 2 7 8 ; 0 c ESC ] 1 1 ; r g b : 0 0 0 0

/ 0 0 0 0 / 0 0 0 0 ESC \ ESC x x t e r m - m o u s

e - m o d e RET ESC [ < 6 5 ; 9 6 ; 4 2 M C-h l$

Pasted below is the output from M-x report-emacs-bug on the failing version. I have also tried emacs 24.5 and found the same bad behavior with the PuTTY client.

In GNU Emacs 24.4.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.10)

of 2015-07-30 on moes

System Description: Debian GNU/Linux 7.7 (wheezy)

Configured using:

`configure --with-xpm=no --with-gif=no --with-tiff=no'

Important settings:

value of $LANG: en_US.UTF-8

locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:

tooltip-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

auto-composition-mode: t

auto-encryption-mode: t

auto-compression-mode: t

buffer-read-only: t

line-number-mode: t

transient-mark-mode: t

Recent input:

ESC [ > 0 ; 1 3 6 ; 0 c ESC x r e p o r t - e m a c

s - b u g RET

Recent messages:

For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:

None found.

Features:

(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml

easymenu mml-sec 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 xterm time-date tooltip electric

uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar

dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-mode

prog-mode register page menu-bar rfn-eshadow timer select scroll-bar

mouse jit-lock font-lock syntax facemenu font-core frame cham georgian

utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean

japanese hebrew greek romanian slovak czech european ethiopic indian

cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev

minibuffer 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 make-network-process

dbusbind gfilenotify dynamic-setting system-font-setting

font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs)

Memory information:

((conses 16 77501 7411)

(symbols 48 17540 0)

(miscs 40 70 113)

(strings 32 9242 4336)

(string-bytes 1 248382)

(vectors 16 7099)

(vector-slots 8 341403 33128)

(floats 8 65 270)

(intervals 56 155 0)

(buffers 960 12)

(heap 1024 7622 527))

From:	GNU bug Tracking System
Subject:	bug#21211: closed (24.4; Possible regression in xterm mouse handling with PuTTY client)
Date:	Mon, 20 Sep 2021 06:11:03 +0000