bug#3578: 23.0.94; when saving some files, diff does not work

[Tiago Saboga <tiagosaboga@gmail.com>]

Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the emacs-pretest-bug@gnu.org mailing list.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

I start emacs with -q and -no-site-file, visit some file, make some
changes, switch to buffer "scratch" (or any other buffer with no
associated file) and run save-some-buffers. It asks me what to do with
the visited file, and I want to view the diff, so I press "d".  And I
get an error message: "Not applicable: no file."

I believe that the problem was introduced by revision 1.985 of files.el,
line 4178, that says:

(if (null buffer-file-name)

and should say:

(if (null buffer-file-name buf)

Thanks,

Tiago Saboga.

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
If you would like to further debug the crash, please read the file
/usr/share/emacs/23.0.94/etc/DEBUG for instructions.


In GNU Emacs 23.0.94.1 (x86_64-pc-linux-gnu, GTK+ Version 2.16.1)
 of 2009-05-25 on elegiac, modified by Debian
 (emacs-snapshot package, version 1:20090525-1)
Windowing system distributor `The X.Org Foundation', version 11.0.10402000
configured using `configure  '--build' 'x86_64-linux-gnu' '--host' 'x86_64-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/23.0.94/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.0.94/site-lisp:/usr/share/emacs/site-lisp' '--with-x=yes' '--with-x-toolkit=gtk' 'build_alias=x86_64-linux-gnu' 'host_alias=x86_64-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: pt_BR.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Alunos

Minor modes in effect:
  show-paren-mode: t
  display-time-mode: t
  tooltip-mode: t
  mouse-wheel-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
  transient-mark-mode: t

Recent messages:
Saving /home/tiago/.newsrc.eld...
Saving file /home/tiago/.newsrc.eld...
Wrote /home/tiago/.newsrc.eld
Saving /home/tiago/.newsrc.eld...done