bug#67259: 29.1; shell/term behavior different from other terminal emulators

[Matt]

I'm helping to maintain Org mode's shell interaction.  The following
was reported to the Org list.

Emacs M-x shell and M-x term executing in term-line-mode both produce
a different result than expected as compared to terminal emulators
like xterm or xfce4-terminal running Bash.  For non-Emacs terminal
emulators, "bar" is echoed.  M-x shell and M-x term executing in
term-line-mode do *not* echo "bar".

To reproduce with M-x shell:

1. emacs -Q
2. M-x shell
3. Copy the following two lines:

ssh localhost "echo foo>foo_file"
echo "bar"

4. Paste them into a non-Emacs terminal emulator (tested with xterm or 
xfce4-terminal) and press return
5. After entering the correct password, "bar" is echoed
6. Paste them into the buffer associated with M-x shell
7. After entering the correct password, "bar" is NOT echoed

To reproduce with M-x term:

1. emacs -Q
2. M-x term
3. C-c C-j to switch to term-line-mode
4. Copy the following two lines:

ssh localhost "echo foo>foo_file"
echo "bar"

5. Paste them into the buffer associated with M-x term
6. After entering the correct password, "bar" is NOT echoed

In GNU Emacs 29.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.37,
cairo version 1.16.0)
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Guix System

Configured using:
 'configure
 
CONFIG_SHELL=/gnu/store/v9p25q9l5nnaixkhpap5rnymmwbhf9rp-bash-minimal-5.1.16/bin/bash
 SHELL=/gnu/store/v9p25q9l5nnaixkhpap5rnymmwbhf9rp-bash-minimal-5.1.16/bin/bash
 --prefix=/gnu/store/xjrhyapm3zwgpmq5baz6m9kavz287jjj-emacs-29.1
 --enable-fast-install --with-cairo --with-modules
 --with-native-compilation=aot --disable-build-details'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES
NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3
THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER X11 XDBE XIM XINPUT2 XPM
GTK3 ZLIB

Important settings:
  value of $EMACSLOADPATH: 
/home/ahab/.guix-profile/share/emacs/site-lisp:/gnu/store/xjrhyapm3zwgpmq5baz6m9kavz287jjj-emacs-29.1/share/emacs/29.1/lisp
  value of $LANG: en_US.utf8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-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
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search time-date mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader cl-loaddefs
comp comp-cstr warnings icons subr-x rx cl-seq cl-macs gv cl-extra
help-mode bytecomp byte-compile cl-lib sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils rmc iso-transl tooltip cconv
eldoc paren electric uniquify ediff-hook vc-hooks lisp-float-type
elisp-mode mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd
fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow
isearch easymenu timer select scroll-bar mouse jit-lock font-lock syntax
font-core term/tty-colors frame minibuffer nadvice seq simple cl-generic
indonesian philippine 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
composite emoji-zwj charscript charprop case-table epa-hook
jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button loaddefs
theme-loaddefs faces cus-face macroexp files window text-properties
overlay sha1 md5 base64 format env code-pages mule custom widget keymap
hashtable-print-readable backquote threads dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting cairo
move-toolbar gtk x-toolkit xinput2 x multi-tty make-network-process
native-compile emacs)

Memory information:
((conses 16 79918 9356)
 (symbols 48 7446 0)
 (strings 32 20277 1733)
 (string-bytes 1 627375)
 (vectors 16 16608)
 (vector-slots 8 334511 19434)
 (floats 8 27 46)
 (intervals 56 235 0)
 (buffers 984 11))