bug#61022: 28.2.50; Mouse tracking of high coordinates not working in rxvt-unicode

[git@vladimir.panteleev.md]

Hi,

For some reason, xt-mouse with xterm-mouse-utf-8 on isn't working for me
under rxvt-unicode. I assume it worked at some point, but it's not
working now.

I investigated it a little and it looks like the (read-char nil nil 0.1)
call is no longer reading an entire UTF-8 character unless the
inherit-input-method argument is non-nil. I don't know why that is.
But, in any case, this patch fixes it for me:

----------------------------------------------------------------------
From 32e4b5ab67006ed08c853396686315ed373691be Mon Sep 17 00:00:00 2001
From: Vladimir Panteleev <git@cy.md>
Date: Sun, 22 Jan 2023 18:54:05 +0000
Subject: [PATCH] Fix xterm mouse tracking of high coordinates with
 xterm-mouse-utf-8

read-char now needs inherit-input-method to be non-nil for it to read
a whole UTF-8 code point, even with set-keyboard-coding-system.

* lisp/xt-mouse.el (xterm-mouse--read-coordinate): Call read-char with
inherit-input-method as t.
---
 lisp/xt-mouse.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/xt-mouse.el b/lisp/xt-mouse.el
index adfa480bc0f..2b6b448305e 100644
--- a/lisp/xt-mouse.el
+++ b/lisp/xt-mouse.el
@@ -160,7 +160,7 @@ xterm-mouse--read-coordinate
              'no-conversion))
           ;; Wait only a little; we assume that the entire escape sequence
           ;; has already been sent when this function is called.
-          (read-char nil nil 0.1))
+          (read-char nil t 0.1))
       (set-keyboard-coding-system previous-keyboard-coding-system))))
 
 ;; In default mode, each numeric parameter of XTerm's mouse report is
-- 
2.38.1
----------------------------------------------------------------------

Reproducer:

- Run urxvt
- In it, run emacs -Q -nw
- M-: (require 'xt-mouse)
- M-: (setq xterm-mouse-utf-8 t)
- M-x xterm-mouse-mode
- Make sure the window is wider than 96 lines or columns
- Move the mouse around past the 96th line or column

Hope this helps.



In GNU Emacs 28.2.50 (build 1, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2022-10-03 built on home.thecybershadow.net
Repository revision: 992611b10a2ef4621b5c936d80cf31644ca3653d
Repository branch: makepkg
System Description: Arch Linux

Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --mandir=/usr/share/man --with-gameuser=:games
 --with-modules --without-libotf --without-m17n-flt --without-gconf
 --without-gsettings --enable-link-time-optimization --with-xinput2
 --with-native-compilation --with-x-toolkit=lucid --with-xft
 --with-xaw3d --without-cairo --with-sound=alsa
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 '--program-transform-name=s/\([ec]tags\)/\1.emacs/'
 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions
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 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
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LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG
SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XAW3D XDBE XFT XIM
XPM LUCID ZLIB

Important settings:
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  value of $LANG: en_US.UTF-8
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Major mode: Magit

Minor modes in effect:
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  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  column-number-mode: t
  line-number-mode: t
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  transient-mark-mode: t

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