GNU bug report logs - #1469
term.el regression when dealing with long lines under bash

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Cyril Bouthors <cyril <at> bouthors.org>
To: emacs-pretest-bug <at> gnu.org
Cc: rfrancoise <at> debian.org, Dimitri Fontaine <dfontaine <at> hi-media.com>
Subject: term.el regression when dealing with long lines under bash
Date: Tue, 02 Dec 2008 14:35:17 +0100

term-mode is no longer able to handle long lines correctly with bash
under emacs-snapshot as it used to work under emacs22.

When a line wider than $COLUMNS+2 is displayed on the terminal, the
cursor is locked on the current line and does not move anymore until
/usr/bin/reset is ran.

I've been able to reproduce this bug when running bash, psql or csh
but not with zsh nor ksh.

I haven't been able to reproduce it under emacs22 at all.

Here's a short procedure to reproduce the bug:
 - Start Emacs: emacs-snapshot -Q
 - Start bash under term-mode: `M-: (term "/bin/bash") RET'
 - Display a long line under bash:
          width=$(($COLUMNS+2))
       for a in $(seq $width); do echo -n X; done; echo
 - Try to type any command on the terminal and you'll see the strange
   cursor behaviour

Long lines typically happen on a daily basis when your are reading
logfiles, running SQL queries, etc.

I hope I provided you with enough information.

In GNU Emacs 23.0.60.1 (x86_64-pc-linux-gnu, GTK+ Version 2.12.11)
 of 2008-11-29 on elegiac, modified by Debian
 (emacs-snapshot package, version 1:20081129-1)
Windowing system distributor `The X.Org Foundation', version 11.0.10502000
configured using `configure  '--build' 'x86_64-linux-gnu' '--host'
'x86_64-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib'
'--libexecdir=/usr/lib' '--localstatedir=/var'
'--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes'
'--enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/23.0.60/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.0.60/site-lisp:/usr/share/emacs/site-lisp'
'--with-x=yes' '--with-x-toolkit=gtk' 'build_alias=x86_64-linux-gnu'
'host_alias=x86_64-linux-gnu' 'CFLAGS=-DDEBIAN
-DSITELOAD_PURESIZE_EXTRA=5000 -g -O2' 'LDFLAGS=-g -Wl,--as-needed'
'CPPFLAGS=''

Important settings:
  value of $LC_ALL: en_US.UTF-8
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Term

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

Recent input:
<return> <return> <up> <return> <return> <return> <return>
<return> <S-return> <return> C-d M-x <up> t e r m <return>
<up> <M-backspace> b a s h <M-backspace> t c s <M-backspace>
c s h <return> <return> <return> <return> <return>
/ b i <backspace> <backspace> <backspace> . / b u <tab>
<tab> <backspace> <backspace> g / l o n g - l i n e
s . s h <return> <return> <return> <return> <return>
C-d M-x <up> <return> <up> <down> <up> C-g C-d M-x
b u <backspace> <backspace> r e p o r t - e m a c s
<tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Quit
#<buffer *terminal*>

-- 	
Cyril Bouthors

Message #10 received at 1469 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: "richardeng" <richardeng <at> foxmail.com>
To: "1469" <1469 <at> debbugs.gnu.org>
Subject: Re: bug#1469 Does anybody working on it?
Date: Sun, 7 Dec 2008 22:08:56 +0800

I have spent some time on it. Fix is not found yet.
I'm sure:
1. problem only in M-x term and M-x ansi-term(both in term.el), M-x shell or M-x eshell(in shell.el or eshell/*.el) works right.
2. The default setting is term-char-mode in term.el, if you change it to term-line-mode, no such problem
3. Problem should be wrong local state(position or coloumn/width/height limitation) after wrap action in function term-emulate-terminal

It's real complex, if somebody is working on it, please share what you found.
Thank you

And Cyril Bouthors, you can temporarily use M-x shell instead of M-x term.

Message #13 received at 1469 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Dan Nicolaescu <dann <at> ics.uci.edu>
To: richardeng <richardeng <at> foxmail.com>
Cc: 1469 <at> debbugs.gnu.org
Subject: Re: bug#1469: Does anybody working on it?
Date: Sun, 7 Dec 2008 10:17:57 -0800 (PST)

"richardeng" <richardeng <at> foxmail.com> writes:

  > I have spent some time on it. Fix is not found yet.
  > I'm sure:
  > 1. problem only in M-x term and M-x ansi-term(both in term.el), M-x shell or M-x eshell(in shell.el or eshell/*.el) works right.
  > 2. The default setting is term-char-mode in term.el, if you change it to term-line-mode, no such problem
  > 3. Problem should be wrong local state(position or coloumn/width/height limitation) after wrap action in function term-emulate-terminal
  > 
  > It's real complex, if somebody is working on it, please share what you found.

Reverting this patch seems to fix the problem:

2008-09-24  Andreas Politz  <politza <at> fh-trier.de>  (tiny change)

            * term.el (term-emulate-terminal): Encode input string
            before
            checking its length.


Another thing, the original bug does not seem to be archived on
gmane.emacs.bug, just this reply...

Message #18 received at 1469 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Nicholas Maniscalco <nicholas <at> maniscalco.com>
To: 1469 <at> debbugs.gnu.org
Subject: patch for term.el regression when dealing with long lines under bash
Date: Fri, 26 Dec 2008 13:12:16 -0800

[Message part 1 (text/plain, inline)]

(I sent this to the wrong list earlier.  Resending to, hopefully, the 
right place this time.)

Here's a patch for bug#1469 (term.el regression when dealing with long 
lines under bash).

* term.el (term-emulate-terminal): Decode substring just prior to 
inserting it.  (Bug#1469)

bug#1469 was introduced while fixing bug#1006.  I verified this patch 
against the repro steps in bug#1006 to make sure I haven't made a 
regression.

Can someone please review?  I'd appreciate any feedback.

-- Nicholas

[term.el.patch (text/x-patch, inline)]

Index: lisp/term.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/term.el,v
retrieving revision 1.107
diff -c -p -r1.107 term.el
*** lisp/term.el	3 Dec 2008 05:48:33 -0000	1.107
--- lisp/term.el	25 Dec 2008 03:45:24 -0000
*************** See `term-prompt-regexp'."
*** 2834,2840 ****
  			  ;; following point if not eob nor insert-mode.
  			  (let ((old-column (current-column))
  				columns pos)
! 			    (insert decoded-substring)
  			    (setq term-current-column (current-column)
  				  columns (- term-current-column old-column))
  			    (when (not (or (eobp) term-insert-mode))
--- 2834,2840 ----
  			  ;; following point if not eob nor insert-mode.
  			  (let ((old-column (current-column))
  				columns pos)
! 				(insert (decode-coding-string (substring str i funny) locale-coding-system))
  			    (setq term-current-column (current-column)
  				  columns (- term-current-column old-column))
  			    (when (not (or (eobp) term-insert-mode))

Message #23 received at 1469-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Dan Nicolaescu <dann <at> ics.uci.edu>
To: Nicholas Maniscalco <nicholas <at> maniscalco.com>
Cc: 1469-done <at> debbugs.gnu.org
Subject: Re: bug#1469: patch for term.el regression when dealing with long lines under bash
Date: Sat, 27 Dec 2008 09:24:40 -0800 (PST)

Nicholas Maniscalco <nicholas <at> maniscalco.com> writes:

  > (I sent this to the wrong list earlier.  Resending to, hopefully, the
  > right place this time.)
  > 
  > Here's a patch for bug#1469 (term.el regression when dealing with long
  > lines under bash).
  > 
  > * term.el (term-emulate-terminal): Decode substring just prior to
  > inserting it.  (Bug#1469)
  > 
  > bug#1469 was introduced while fixing bug#1006.  I verified this patch
  > against the repro steps in bug#1006 to make sure I haven't made a
  > regression.
  > 
  > Can someone please review?  I'd appreciate any feedback.

Thanks, I checked this in.

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