bug#13165: Fwd: Newlines in file names

[Whitfield Diffie]

    Since this didn't attract much attention as a request for help,
let me try it as a bug report.

    In emacs 22.1.1, if you have a file whose name contains a carriage
return and put the cursor on the line with that file in dired, then
(file-exists-p (dired-get-filename)) is nil.

                                               Whit


---------- Forwarded message ----------
From: Whitfield Diffie <whitfield.diffie@gmail.com>
Date: Mon, Dec 10, 2012 at 11:47 AM
Subject: Newlines in file names
To: help-gnu-emacs@gnu.org


Question: How do you translate a filename containing a newline to one
containing a \n without getting a \\n.

Problem: Create a directory ``test''.

         In the directory create a file with

                 (call-process "touch" nil nil nil "Icon\n").

         This file's name has five characters of which the last is a
         newline. (Such files appear in some downloads.)

         This directory now appears as

                /Users/diffie/test:
                total used in directory 0 available 327738716
                drwxr-xr-x   3 diffie  staff  102 Dec 10 11:04 .
                drwxr-xr-x  25 diffie  staff  850 Dec 10 11:03 ..
                -rw-r--r--   1 diffie  staff    0 Dec  9 10:01 Icon

         Place the cursor on the line with the Icon file and type

                <esc>: (file-exists-p (dired get filename))

         The response is ``nil''.

         Make the buffer writable with <ctrl-x><ctrl-q> and edit the
         name by hand to ``Icon\n''.  Type

                <esc>: (file-exists-p (dired-get-filename))

         The response is now ``t''.

         Type g to revert the buffer and the name returns to being ``Icon''.

         Place the cursor on the line with the Icon file again and type

                M+x

         The entire file line disappears leaving only . and ..  in the
          directory.

         Type g to revert the buffer and the line reappears but the file
         has not become executable.

         Edit the filename as before and repeat the attempt to make it
         executable.

         Now the file line becomes

                -rwxr-xr-x   1 diffie  staff    0 Dec  9 10:01 Icon

         The file has become executable but its name has returned to being
         ``Icon'', lacks the newline character.

Objective: Repair dired so that filenames containing newlines are displayed
           with \n in place of newline characters (and \r in place of carriage
           returns).

           I have tried setting print-escape-newlines to t and recoding
           filename with buffer-file-coding-system, file-name-coding-system,
           and default-file-name-coding-system, without success.


                                             Whit