bug#7339: 23.2; term-mode vs clone-buffer

bug#7339: 23.2; term-mode vs clone-buffer

[Kevin Ryde]

A term-mode buffer doesn't seem to duplicate with M-x clone-buffer very
well.  For example

    emacs -Q
    M-x term
    top Ret        ;; run the "top" program
    C-c M-x clone-buffer
    => gets multiple inserts of the top output

where I hoped the cloned buffer would have refreshing top output,
instead of appending and growing the buffer.

Nosing around the code it looks like clone-buffer runs up a new
subprocess well enough, but that presumably something in the `term-mode'
setups doesn't come out right.

A line-oriented program like the default /bin/bash that M-x term offers
seems a bit better, though point isn't left at the end of the new
prompt.



In GNU Emacs 23.2.1 (i486-pc-linux-gnu, GTK+ Version 2.20.0)
 of 2010-05-16 on raven, modified by Debian
configured using `configure  '--build' 'i486-linux-gnu' '--build' 'i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var/lib' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.2/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.2/leim' '--with-x=yes' '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars' 'build_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -g -O2' 'LDFLAGS=-g' 'CPPFLAGS=''

Important settings:
  value of $LC_ALL: nil
  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_AU
  value of $XMODIFIERS: nil
  locale-coding-system: iso-latin-1-unix
  default enable-multibyte-characters: t

bug#7339: 23.2; term-mode vs clone-buffer

[Lars Ingebrigtsen]

Kevin Ryde <user42@zip.com.au> writes:

> A term-mode buffer doesn't seem to duplicate with M-x clone-buffer very
> well.  For example
>
>     emacs -Q
>     M-x term
>     top Ret        ;; run the "top" program
>     C-c M-x clone-buffer
>     => gets multiple inserts of the top output
>
> where I hoped the cloned buffer would have refreshing top output,
> instead of appending and growing the buffer.
>
> Nosing around the code it looks like clone-buffer runs up a new
> subprocess well enough, but that presumably something in the `term-mode'
> setups doesn't come out right.

(I'm going through old bug reports that unfortunately weren't resolved
at the time.)

I can confirm that this behaviour is still present in Emacs 29.

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