bug#2893: 23.0.91; vc-diff on git-controlled file fails

[David Abrahams]

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 did `M-x v =' and got this:

Debugger entered--Lisp error: (wrong-type-argument stringp 
("/Users/dave/src/elisp.repo/elisp/custom.el"))
  expand-file-name(("/Users/dave/src/elisp.repo/elisp/custom.el"))
  file-relative-name(("/Users/dave/src/elisp.repo/elisp/custom.el"))
  vc-git-diff(("/Users/dave/src/elisp.repo/elisp/custom.el") nil nil 
"*vc-diff*")
  apply(vc-git-diff (("/Users/dave/src/elisp.repo/elisp/custom.el") nil nil 
"*vc-diff*"))
  vc-call-backend(Git diff ("/Users/dave/src/elisp.repo/elisp/custom.el") nil 
nil "*vc-diff*")
  vc-diff-internal(t (Git ("/Users/dave/src/elisp.repo/elisp/custom.el")) nil 
nil t)
  vc-diff(nil t)
  call-interactively(vc-diff nil nil)


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
/Applications/Emacs.app/Contents/Resources/etc/DEBUG for instructions.


In GNU Emacs 23.0.91.1 (i386-apple-darwin9.6.0, NS apple-appkit-949.43)
 of 2009-03-05 on black.local
Windowing system distributor `Apple', version 10.3.949
configured using `configure  '--with-ns''

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: nil
  value of $XMODIFIERS: nil
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  diff-auto-refine-mode: t
  shell-dirtrack-mode: t
  show-paren-mode: t
  server-mode: t
  global-auto-revert-mode: t
  delete-selection-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
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x C-n M-< C-s C-x C-p G C-n C-n C-n C-n C-n C-n C-n 
C-p <tab> <tab> C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-n C-p s p p s s s s C-s g n u 
s C-a C-p s M-> C-p C-p <tab> C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-n M-> C-SPC M-< M-w C-p C-n C-n 
C-n C-p C-p C-s a n d b a <backspace> 5 <backspace> 
4 a c k C-n C-n C-n M-x m a g i <tab> <tab> b u g <tab> 
<backspace> <backspace> <backspace> <backspace> r e 
<backspace> <backspace> - r e p <tab> C-g C-g C-x C-n 
C-x C-p C-x b * G r <tab> C-g C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-p C-p 1 2 3 4 3 2 1 2 3 4 C-x C-n C-s u n s t 
a g e C-a C-p C-p C-p C-p C-x C-p U C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
p n p n p n <return> C-x C-b C-p C-p C-p C-p C-p C-p 
C-x C-b C-x v = <wheel-up> <double-wheel-up> <wheel-down> 
<double-wheel-down> <triple-wheel-up> <down-mouse-1> 
<mouse-1> C-a <menu-bar> <options> <debug-on-error> 
<down-mouse-1> <mouse-1> C-x v = C-x C-n C-x C-n C-p 
C-SPC C-n C-n C-n C-n C-n C-n C-n C-n C-n M-w C-x C-p 
M-x r e p o r t - e m a <tab> <return>

Recent messages:
Quit [3 times]
Mark saved where search started
`working-revision' not found: using the old `workfile-version' instead
Mark set
Finding changes in /Users/dave/src/elisp.repo/elisp/custom.el...
file-relative-name: Wrong type argument: stringp, 
("/Users/dave/src/elisp.repo/elisp/custom.el")
Debug on Error enabled globally
Finding changes in /Users/dave/src/elisp.repo/elisp/custom.el...
Entering debugger...
Mark set

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com