bug#19084: 24.4; C-x v + should work from the *vc-change-log* buffer

[Eli Zaretskii <eliz@gnu.org>]

Right now, it doesn't:

  emacs -Q
  C-x v L /some/git-managed/directory/ RET
  C-x v +
  => vc-deduce-fileset: Buffer *vc-change-log* is not associated with a file

This is less helpful than Emacs could be: the default-directory of the
*vc-change-log* buffer is the top-level repository directory.

Here's the patch to fix that:

--- vc/vc.el~	2014-03-21 07:34:40.000000000 +0200
+++ vc/vc.el	2014-11-17 19:22:01.358500000 +0200
@@ -985,6 +985,9 @@
       (if observer
 	  (vc-dired-deduce-fileset)
 	(error "State changing VC operations not supported in `dired-mode'")))
+     ((and (derived-mode-p 'log-view-mode)
+	   (setq backend (vc-responsible-backend default-directory)))
+      (list backend default-directory))
      ((setq backend (vc-backend buffer-file-name))
       (if state-model-only-files
 	(list backend (list buffer-file-name)


OK to commit (with the appropriate log message)?

In GNU Emacs 24.4.1 (i686-pc-mingw32)
 of 2014-10-17 on HOME-C4E4A596F7
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --prefix=/d/usr'

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: Git-Log-View

Minor modes in effect:
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x v L <M-backspace> <M-backspace> <M-backspace> g 
n <tab> g i <tab> t <tab> / e m <tab> t r <tab> <return> 
C-x 1 C-x v + <help-echo> <help-echo> <help-echo> <help-echo> 
M-x r e p o r t - e m <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Making completion list...
vc-deduce-fileset: Buffer *vc-change-log* is not associated with a file

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
help-fns mail-prsvr mail-utils add-log log-view easy-mmode pcvs-util
vc-git vc-bzr vc-sccs vc-svn vc-cvs vc-rcs help-mode easymenu vc
vc-dispatcher time-date tooltip electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel dos-w32 ls-lisp w32-common-fns disp-table w32-win
w32-vars tool-bar dnd fontset image regexp-opt fringe tabulated-list
newcomment lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai
tai-viet lao korean japanese hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help
simple abbrev minibuffer nadvice loaddefs button faces cus-face macroexp
files text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
w32notify w32 multi-tty emacs)

Memory information:
((conses 8 83636 6422)
 (symbols 32 18627 0)
 (miscs 32 35 139)
 (strings 16 15190 3836)
 (string-bytes 1 376959)
 (vectors 8 11257)
 (vector-slots 4 401567 5536)
 (floats 8 58 271)
 (intervals 28 556 127)
 (buffers 508 13))