bug#1960: 23.0.60; A combination of PC Selection, Visual Lines and emacsclient redefines C-backspace

bug#1960: 23.0.60; A combination of PC Selection, Visual Lines and emacsclient redefines C-backspace

[pent]

1) Run emacs

2) Hit C-h k C-backspace 

   It replies (expected):

   <C-backspace> runs the command backward-kill-word, which is an
   interactive compiled Lisp function.

   It is bound to <C-backspace>.

   (backward-kill-word arg)

   Kill characters backward until encountering the beginning of a word.
   With argument arg, do this that many times.

3) Exit emacs

4) Run emacs --daemon

5) Run emacsclient -c

6) Hit C-h k C-backspace

   It tells (unexpected):

   <C-backspace> runs the command kill-visual-line, which is an
   interactive compiled Lisp function.

   It is bound to <deleteline>, <C-backspace>, C-k.

   (kill-visual-line &optional arg)

   Kill the rest of the visual line.
   If there are only whitespace characters there, kill through the
   newline as well.

   ...

The problem is not reproduced with emacs -Q. However, I could trace
down the problematic line in my .emacs (see listing below). The
problem is triggered by '(pc-selection-mode t) statement.

Please note that *do* like the [other] effects of PC Selection and
Visual Lines modes and I've turned them on on purpose.

My .emacs customizations:

;; --- Customized ---
(custom-set-variables
  ;; custom-set-variables was added by Custom.
  ;; If you edit it by hand, you could mess it up, so be careful.
  ;; Your init file should contain only one such instance.
  ;; If there is more than one, they won't work right.
 '(TeX-PDF-mode t)
 '(TeX-output-view-style (quote (("^dvi$" ("^landscape$" "^pstricks$\\|^pst-\\|^psfrag$") "%(o?)dvips -t landscape %d -o && gv %f") ("^dvi$" "^pstricks$\\|^pst-\\|^psfrag$" "%(o?)dvips %d -o && gv %f") ("^dvi$" ("^\\(?:a4\\(?:dutch\\|paper\\|wide\\)\\|sem-a4\\)$" "^landscape$") "%(o?)xdvi %dS -paper a4r -s 0 %d") ("^dvi$" "^\\(?:a4\\(?:dutch\\|paper\\|wide\\)\\|sem-a4\\)$" "%(o?)xdvi %dS -paper a4 %d") ("^dvi$" ("^\\(?:a5\\(?:comb\\|paper\\)\\)$" "^landscape$") "%(o?)xdvi %dS -paper a5r -s 0 %d") ("^dvi$" "^\\(?:a5\\(?:comb\\|paper\\)\\)$" "%(o?)xdvi %dS -paper a5 %d") ("^dvi$" "^b5paper$" "%(o?)xdvi %dS -paper b5 %d") ("^dvi$" "^letterpaper$" "%(o?)xdvi %dS -paper us %d") ("^dvi$" "^legalpaper$" "%(o?)xdvi %dS -paper legal %d") ("^dvi$" "^executivepaper$" "%(o?)xdvi %dS -paper 7.25x10.5in
  %d") ("^dvi$" "." "%(o?)xdvi %dS %d") ("^pdf$" "." "evince %o") ("^html?$" "." "firefox %o"))))
 '(TeX-save-query nil)
 '(case-fold-search t)
 '(column-number-mode t)
 '(csv-align-style (quote right))
 '(current-language-environment "UTF-8")
 '(debian-bug-From-address "Andrey <cmr.Pent@gmail.com>")
 '(debian-bug-use-From-address t)
 '(dictionary-create-buttons nil)
 '(dictionary-default-dictionary "ru-en--en-ru")
 '(dictionary-server "dict.dvo.ru")
 '(dired-listing-switches "-l --group-directories-first")
 '(ediff-split-window-function (quote split-window-horizontally))
 '(ediff-window-setup-function (quote ediff-setup-windows-plain))
 '(global-visual-line-mode t)
 '(gnus-select-method (quote (nntp "news.gmane.org")))
 '(ibuffer-enable t)
 '(ibuffer-never-show-predicates (quote ("^\\*.*")) nil (ibuf-ext))
 '(kill-whole-line t)
 '(list-directory-brief-switches "-CF --group-directories-first")
 '(list-directory-verbose-switches "-l --group-directories-first")
 '(mouse-wheel-mode t)
 '(org-insert-mode-line-in-empty-file t)
 '(pc-selection-mode t)
 '(scroll-conservatively 50)
 '(scroll-margin 5)
 '(scroll-preserve-screen-position t)
 '(show-paren-mode t)
 '(svn-status-default-export-directory "~/study")
 '(svn-status-preserve-window-configuration t)
 '(text-mode-hook (quote (turn-on-auto-fill text-mode-hook-identify)))
 '(tool-bar-mode nil)
 '(truncate-lines t)
 '(use-dialog-box nil)
 '(w3m-coding-system (quote utf-8))
 '(w3m-default-coding-system (quote utf-8))
 '(w3m-file-coding-system (quote utf-8))
 '(w3m-file-name-coding-system (quote utf-8))
 '(w3m-terminal-coding-system (quote utf-8))
 '(w3m-use-cookies t)
 '(x-select-enable-clipboard t)
 '(x-select-request-type (quote UTF8_STRING) t))

I'm ready to provide any additional info,
Andrey

In GNU Emacs 23.0.60.1 (i486-pc-linux-gnu, GTK+ Version 2.12.11)
 of 2009-01-18 on elegiac, modified by Debian
 (emacs-snapshot package, version 1:20090118-1)
Windowing system distributor `The X.Org Foundation', version 11.0.10402000
configured using `configure  '--build' 'i486-linux-gnu' '--host' 'i486-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=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -DSITELOAD_PURESIZE_EXTRA=5000 -g -O2' 'LDFLAGS=-g -Wl,--as-needed' '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: ru_RU.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  delete-selection-mode: t
  show-paren-mode: t
  pc-selection-mode: t
  shell-dirtrack-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  global-visual-line-mode: t
  visual-line-mode: t
  transient-mark-mode: t

bug#1960: 23.0.60; A combination of PC Selection, Visual Lines and emacsclient redefines C-backspace

[Chong Yidong]

Simplified recipe for bug#1960:

1. Put (pc-selection-mode 1) in .emacs
2. emacs --daemon
3. emacsclient -c
4. C-h k C-backspace

<C-backspace> runs the command kill-line, which is an interactive
compiled Lisp function in `simple.el'.

5. C-x C-c
6. emacsclient -c
7. C-h k C-backspace

<C-backspace> runs the command backward-kill-word, which is an
interactive compiled Lisp function in `simple.el'.


PC-selection mode binds [C-delete] to kill-line.  My guess is that some
code for distinguishing delete from DEL isn't run when Emacs is started
as a daemon.  It's only run sometime after the first client frame is
created, which is why C-backspace works properly for the second client
frame.

Could someone take a closer look?

bug#1960: 23.0.60; A combination of PC Selection, Visual Lines and emacsclient redefines C-backspace

[Dan Nicolaescu]

Chong Yidong <cyd@stupidchicken.com> writes:

  > Simplified recipe for bug#1960:
  > 
  > 1. Put (pc-selection-mode 1) in .emacs
  > 2. emacs --daemon
  > 3. emacsclient -c
  > 4. C-h k C-backspace
  > 
  > <C-backspace> runs the command kill-line, which is an interactive
  > compiled Lisp function in `simple.el'.
  > 
  > 5. C-x C-c
  > 6. emacsclient -c
  > 7. C-h k C-backspace
  > 
  > <C-backspace> runs the command backward-kill-word, which is an
  > interactive compiled Lisp function in `simple.el'.

What happens when repeating steps 5,6 and 7? 
I am guessing that the <C-backspace> binding would toggle between
kill-line and backward-kill-word.  
If that's indeed the case, then there's probably some problem with
pc-selection-mode and the way it interacts with
normal-erase-is-backspace.

bug#1960: 23.0.60; A combination of PC Selection, Visual Lines and emacsclient redefines C-backspace

[Chong Yidong]

Dan Nicolaescu <dann@tensilica.com> writes:

> there's probably some problem with pc-selection-mode and the way it
> interacts with normal-erase-is-backspace.

The problem is not pc-selection mode, but how Emacs does
normal-erase-is-backspace in multi-tty situations.  Here's an even
simpler recipe, not involving pc-selection-mode or the daemon:

1. Add the following line to .emacs:

     (global-set-key [C-delete] 'kill-line)

2. emacs -nw -f server-start
3. emacsclient -c
4. C-h k C-backspace

  => <C-backspace> runs the command kill-line

bug#1960: 23.0.60; A combination of PC Selection, Visual Lines and emacsclient redefines C-backspace

[Dan Nicolaescu]

  > > there's probably some problem with pc-selection-mode and the way it
  > > interacts with normal-erase-is-backspace.
  > 
  > The problem is not pc-selection mode, but how Emacs does
  > normal-erase-is-backspace in multi-tty situations.  Here's an even
  > simpler recipe, not involving pc-selection-mode or the daemon:
  > 
  > 1. Add the following line to .emacs:
  > 
  >      (global-set-key [C-delete] 'kill-line)
  > 
  > 2. emacs -nw -f server-start
  > 3. emacsclient -c
  > 4. C-h k C-backspace
  > 
  >   => <C-backspace> runs the command kill-line


This happens because:

(defun normal-erase-is-backspace-setup-frame (&optional frame)
  "Set up `normal-erase-is-backspace-mode' on FRAME, if necessary."
  (unless frame (setq frame (selected-frame)))
  (unless (terminal-parameter nil 'normal-erase-is-backspace)
    (normal-erase-is-backspace-mode
      (if (if (eq normal-erase-is-backspace 'maybe)

When using "emacs -nw -f server-start" the "(unless (terminal-parameter"
test passes and `normal-erase-is-backspace' is run.

When using "emacs -f server-start" the `terminal-parameter' call returns
non-ni, so `normal-erase-is-backspace' is not run.  
It seems that terminal-parameters are copied from the first frame
created...

Not sure how normal-erase-is-backspace is supposed to work...