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

[Dan Nicolaescu]

David Abrahams <dave@boostpro.com> writes:

  > 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:

Is the above actually `C-x v =' ?

Can you please show how to reproduce this step by step starting from "emacs -Q"?
Can you reproduce the problem on GNU/Linux?

  > 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