GNU bug report logs - #1279
color output from external programs not working by default in eshell

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

From: David Miani <nanothief <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org, jasonspiro4 <at> gmail.com
Subject: color output from external programs not working by default in eshell
Date: Fri, 31 Oct 2008 02:39:44 +1000

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

When running eshell, using an external program that outputs in color results 
in the raw terminal escape codes being displayed. For example,
~ $ yaourt -Ss emacs
^[[3m^[[1;32mextra/^[[0m^[[0m^[[1memacs ^[[1;32m22.3-1 
^[[7m^[[1;33m[installed]^[[0m ^[[1;34m^[[0m
^[[3m     The Emacs Editor^[[0m
^[[3m^[[1;32mextra/^[[0m^[[0m^[[1msnd ^[[1;32m10.1-1^[[0m ^[[1;34m^[[0m
^[[3m     Snd is the emacs of sound editor^[[0m
^[[3m^[[1;32mextra/^[[0m^[[0m^[[1mtexmacs ^[[1;32m1.0.6.14-1^[[0m 
^[[1;34m^[[0m
^[[3m     GNU TeXmacs is a free scientific text editor, which was both 
inspired by TeX^[[0m
...

However, if the following code is used in ~/.emacs (code found at 
http://www.emacswiki.org/emacs/EshellColor):
    (require 'ansi-color)
    (require 'eshell)
    (defun eshell-handle-ansi-color ()
      (ansi-color-apply-on-region eshell-last-output-start
                                  eshell-last-output-end))
    (add-to-list 'eshell-output-filter-functions 'eshell-handle-ansi-color)

the output is correctly displayed in color as:
$ yaourt -Ss emacs
extra/emacs 22.3-1 [installed] 
     The Emacs Editor
extra/snd 10.1-1 
     Snd is the emacs of sound editor
extra/texmacs 1.0.6.14-1 
     GNU TeXmacs is a free scientific text editor, which was both inspired by 
TeX
...

I think that this should be included and enabled by default with eshell, as it 
doesn't change existing behaviour for non-color output, it only makes color 
output readable. I have a fair few programs that output in color, and the 
default behaviour made eshell unusable for me.

In GNU Emacs 22.3.1 (i686-pc-linux-gnu, GTK+ Version 2.12.11)
 of 2008-09-09 on p15200770.pureserver.info
Windowing system distributor `The X.Org Foundation', version 11.0.10402000
configured using `configure  '--prefix=/usr' '--sysconfdir=/etc' '--
libexecdir=/usr/lib' '--localstatedir=/var' '--mandir=/usr/share/man' '--
without-sound' '-with-x-toolkit=gtk' 'CFLAGS=-march=i686 -mtune=generic -O2 -
pipe''

[Message part 2 (text/html, inline)]

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

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: David Miani <nanothief <at> gmail.com>
Cc: 1279 <at> debbugs.gnu.org, bug-gnu-emacs <at> gnu.org,
        jasonspiro4 <at> gmail.com
Subject: Re: bug#1279: color output from external programs not working by default in eshell
Date: Thu, 30 Oct 2008 23:36:24 -0400

> When running eshell, using an external program that outputs in color results 
> in the raw terminal escape codes being displayed. For example,
> ~ $ yaourt -Ss emacs
> ^[[3m^[[1;32mextra/^[[0m^[[0m^[[1memacs ^[[1;32m22.3-1 
> ^[[7m^[[1;33m[installed]^[[0m ^[[1;34m^[[0m
> ^[[3m     The Emacs Editor^[[0m
> ^[[3m^[[1;32mextra/^[[0m^[[0m^[[1msnd ^[[1;32m10.1-1^[[0m ^[[1;34m^[[0m
> ^[[3m     Snd is the emacs of sound editor^[[0m
> ^[[3m^[[1;32mextra/^[[0m^[[0m^[[1mtexmacs ^[[1;32m1.0.6.14-1^[[0m 
> ^[[1;34m^[[0m
> ^[[3m     GNU TeXmacs is a free scientific text editor, which was both 
> inspired by TeX^[[0m
> ...

FWIW, I consider it a bug for such programs to output ANSI escape
sequences for color unless they have some concrete evidence that the
terminal to which they talk does understand those escape sequences.

What does $TERM say in your shell?  Is this terminal type known to
support color?  If so, specifying such a terminal type is an error and
we try and figure out where it comes from so we can fix it.


        Stefan

Message #20 received at 1279 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: nanothief <davidmiani <at> gmail.com>
To: 1279 <at> debbugs.gnu.org
Subject: Re: bug#1279: color output from external programs not working by default in eshell
Date: Sat, 1 Nov 2008 12:27:15 +1000

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

> What does $TERM say in your shell?  Is this terminal type known to
> support color?  If so, specifying such a terminal type is an error and
> we try and figure out where it comes from so we can fix it.
Well running in eshell echo $TERM gives no output. and I often get the error 
message "tput: No value for $TERM and no -T specified". Running the command 
export TERM="dumb" stops the error messages, but the program still outputs in 
color.

Note that the program probably doesn't work correctly with a non-color shell, 
as it is meant as an advancement on another program, so it is unlikely the 
developers tested it with a non-color term. 

However, I'm not sure how relevant this is to this bug, as if eshell can be 
made to work easily with color, then why not set it as default?

[Message part 2 (text/html, inline)]

Message #25 received at 1279-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: 1279-done <at> debbugs.gnu.org
Subject: Re: color output from external programs not working by default in eshell
Date: Wed, 21 Jan 2009 23:46:53 -0500

The 2009-01-21 checkin by John Wiegley fixes this.

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