bug#49186: ansi-term switch to char mode immediately executes string at prompt

bug#49186: ansi-term switch to char mode immediately executes string at prompt

[simon254--- via Bug reports for GNU Emacs, the Swiss army knife of text editors]

One can switch from char-mode to line-mode via C-c C-j to copy text /
enter text etc. Unfortunately, when changing back to char-mode, it always sends a return to the shell.
This was not the case in emacs 26

For example, C-c C-j, then typing ls and then C-c C-k -> ls is
executed. However, If I type ls and then C-c C-j followed by C-c C-k, it does not execute ls

Bug affects emacs version 27 and 28

In GNU Emacs 28.0.50 (build 1, x86_64-apple-darwin20.5.0, NS appkit-2022.50 Version 11.4 (Build 20F71))
 of 2021-06-06 built on two.local
Windowing system distributor 'Apple', version 10.3.2022
System Description:  macOS 11.4

Configured using:
 'configure --disable-dependency-tracking --disable-silent-rules
 --enable-locallisppath=/usr/local/share/emacs/site-lisp
 --infodir=/usr/local/Cellar/emacs-plus@28/28.0.50/share/info/emacs
 --prefix=/usr/local/Cellar/emacs-plus@28/28.0.50 --with-xml2
 --with-gnutls --with-native-compilation --without-dbus
 --with-imagemagick --with-modules --with-rsvg --with-ns
 --disable-ns-self-contained 'CFLAGS=-I/usr/local/opt/gcc/include
 -I/usr/local/opt/libgccjit/include -I/usr/local/opt/gmp/include
 -I/usr/local/opt/jpeg/include' 'LDFLAGS=-L/usr/local/lib/gcc/11
 -I/usr/local/opt/gcc/include -I/usr/local/opt/libgccjit/include
 -I/usr/local/opt/gmp/include -I/usr/local/opt/jpeg/include''

Configured features:
ACL GIF GLIB GMP GNUTLS IMAGEMAGICK JPEG JSON LCMS2 LIBXML2 MODULES
NATIVE_COMP NOTIFY KQUEUE NS PDUMPER PNG RSVG THREADS TIFF
TOOLKIT_SCROLL_BARS XIM ZLIB

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

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  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

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail
rmail-loaddefs auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache json map text-property-search time-date
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term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-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 cl-generic cham georgian utf-8-lang
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loaddefs faces cus-face macroexp files window text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote threads kqueue cocoa ns lcms2
multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 68746 8679)
 (symbols 48 6527 0)
 (strings 32 18707 1877)
 (string-bytes 1 646131)
 (vectors 16 14337)
 (vector-slots 8 288368 17073)
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 (intervals 56 262 0)
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bug#49186: ansi-term switch to char mode immediately executes string at prompt

[Lars Ingebrigtsen]

simon254--- via "Bug reports for GNU Emacs, the Swiss army knife of text
editors" <bug-gnu-emacs@gnu.org> writes:

> For example, C-c C-j, then typing ls and then C-c C-k -> ls is
> executed. However, If I type ls and then C-c C-j followed by C-c C-k, it does not execute ls
>
> Bug affects emacs version 27 and 28

I can reproduce the behaviour.  To reproduce:

emacs -Q
M-x ansi-term RET RET
`C-c C-j l s C-c C-k'

In Emacs 26, this won't execute ls, but in Emacs 28 it does (and so it
does in Emacs 25.1).

The code for `term-char-mode' (i.e., `C-c C-k') seems to indicate that
the intention of the `C-c C-k' was to behave like Emacs 28 does now:

    ;; Send existing partial line to inferior (without newline).
    (let ((pmark (process-mark (get-buffer-process (current-buffer))))
	  (save-input-sender term-input-sender))
      (when (> (point) pmark)
	(unwind-protect
	    (progn
	      (setq term-input-sender
		    (symbol-function 'term-send-string))
	      (end-of-line)
	      (term-send-input))
	  (setq term-input-sender save-input-sender))))

But this didn't work in Emacs 26.1, but has been fixed now.

I don't use ansi-term myself much -- I think it's pretty peculiar that
`C-c C-k' sends partial line inputs to the shell.  Does anybody know
what the rationale for this is?  The code has been like this since 1994,
and Emacs 25 works like Emacs 28.  (So it's Emacs 26.1 that's broken
here.)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#49186: ansi-term switch to char mode immediately executes string at prompt

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> I don't use ansi-term myself much -- I think it's pretty peculiar that
> `C-c C-k' sends partial line inputs to the shell.  Does anybody know
> what the rationale for this is?  The code has been like this since 1994,
> and Emacs 25 works like Emacs 28.  (So it's Emacs 26.1 that's broken
> here.)

I've now made term-char-mode document what it does.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no