Tramp mode and auto-conversion of files to DOS line endings

[<David Howells]

Symptoms:

I'm seeing a problem with Tramp in which when I save a file or revisit it,
emacs changes its mind on the type of line endings to DOS mode, whether or not
the file was DOS mode before.

The result of the initial save on disk doesn't contain CR characters, but
subsequent saves do.

I see this with both the SCP and SSH protocol handlers.

This happens with various combinations of x86, ppc or x86_64, with FC4 on the
client and, RHEL3, RHEL4 or FC4 on the server.

Stracing emacs doesn't show it loading the file back in after making a save,
so I don't know where it's getting the idea that it's become DOS format from.

This doesn't happen with normal non-Tramp file operations.

Setting file-precious-flag to nil rather than t seems to stop the problem from
occurring.



In GNU Emacs 22.0.50.4 (x86_64-unknown-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2005-06-10 on warthog.cambridge.redhat.com
Distributor `The X.Org Foundation', version 11.0.60802000
configured using `configure '--prefix=/warthog/emacs64''

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_GB.utf8
  locale-coding-system: utf-8
  default-enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  auto-compression-mode: t
  display-time-mode: t
  mouse-wheel-mode: t
  tooltip-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  line-number-mode: t
  next-error-follow-minor-mode:  Fol

Recent input:
<return> C-e b C-x C-s c C-x C-s C-x k <return> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <down-mouse-1> 
<mouse-1> <help-echo> <help-echo> <help-echo> <down-mouse-1> 
<mouse-1> C-x k <return> C-x C-f <up> <C-left> <C-left> 
<C-left> <C-right> <C-backspace> j o l t <return> a 
a a a a a a a a a C-x C-s C-x k <return> C-x C-f <up> 
<C-left> <C-left> <C-left> <C-right> <C-backspace> 
p e p s i <return> a a a a a a a a C-x C-s C-x k <return> 
<down-mouse-1> <mouse-1> C-x C-f <up> <return> C-e 
a C-x C-s M-x C-g <help-echo> <help-echo> <help-echo> 
<help-echo> <menu-bar> <help-menu> <report-emacs-b
ug>

Recent messages:
tramp: Process has finished.
tramp: Transferring /tmp/tramp.151848Vu to file /scp:pepsi:/tmp/wibble~...done
tramp: Transferring /tmp/tramp.151847pD to file /scp:pepsi:/tmp/tmp15184Jg0...
tramp: Waiting for prompts from remote shell
tramp: Waiting 60s for prompt from remote shell
tramp: Process has finished.
tramp: Transferring /tmp/tramp.151847pD to file 
/scp:pepsi:/tmp/tmp15184Jg0...done
Wrote /scp:pepsi:/tmp/tmp15184Jg0
Quit
Loading emacsbug...done