bug#31763: 26.1; Unable to visit git revision in compact-style vc log buffer

[Carlos Pita]

I created a test git repo, add a file, make a few changes, commit a few
revisions. Now I open the compact log buffer for the file (C-x v L) and
when I try to visit a revision (f) I get, for instance:

  Checking out /tmp/repo/.~69ad211~...
  vc-find-backend-function: Cannot open load file: No such file or directory, 
vc-nil

Take into account that:

1. From the normal log buffer (C-x v l) the above works as documented.
2. The compact log buffer is still able to show revision diffs (d).

---

In GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
 of 2018-05-29 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.11906000
System Description:     Manjaro Linux

Recent messages:
Checking out /tmp/repo/.~69ad211~...
vc-find-backend-function: Cannot open load file: No such file or directory, 
vc-nil
Checking out /tmp/repo/.~69ad211~...
vc-find-backend-function: Cannot open load file: No such file or directory, 
vc-nil
Checking out /tmp/repo/.~69ad211~...
vc-find-backend-function: Cannot open load file: No such file or directory, 
vc-nil
Checking out /tmp/repo/.~69ad211~...
vc-find-backend-function: Cannot open load file: No such file or directory, 
vc-nil
Quit
next-line: End of buffer [10 times]

Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --with-x-toolkit=gtk3 --with-xft --with-modules
 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong
 -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY
ACL GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS
GTK3 X11 MODULES THREADS LIBSYSTEMD LCMS2

Important settings:
  value of $LC_MONETARY: en_US.UTF-8
  value of $LC_NUMERIC: en_US.UTF-8
  value of $LC_TIME: en_US.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Messages

Minor modes in effect:
  diff-auto-refine-mode: t
  pyvenv-mode: t
  shell-dirtrack-mode: t
  winner-mode: t
  show-paren-mode: t
  ido-ubiquitous-mode: t
  ido-everywhere: t
  global-company-mode: t
  company-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-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
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg gnus-util rmail rmail-loaddefs
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils vc-annotate vc-dir ewoc vc-filewise add-log log-view
pcvs-util vc vc-dispatcher vc-git display-line-numbers server
doom-themes-org cl-extra yasnippet elec-pair highlight-indentation
help-fns radix-tree help-mode elpy find-file-in-project ivy delsel
ivy-overlay ffap thingatpt windmove diff-mode easy-mmode elpy-shell
pyvenv esh-var esh-io esh-cmd esh-opt esh-ext esh-proc esh-arg
esh-groups eshell esh-module esh-mode esh-util elpy-profile elpy-django
elpy-refactor subr-x python tramp-sh tramp tramp-compat tramp-loaddefs
trampver ucs-normalize shell pcomplete parse-time format-spec advice
json map grep compile comint ansi-color files-x company-oddmuse
company-keywords company-etags etags xref project company-gtags
company-dabbrev-code company-dabbrev company-files company-capf
company-cmake company-xcode company-clang company-semantic company-eclim
company-template company-css company-nxml company-bbdb
doom-tomorrow-night-theme doom-themes doom-themes-common winner ring
paren ido-completing-read+ memoize s cus-edit wid-edit minibuf-eldef ido
company edmacro kmacro pcase cus-start cus-load finder-inf info package
easymenu epg-config url-handlers url-parse auth-source cl-seq eieio
eieio-core cl-macs eieio-loaddefs password-cache url-vars seq byte-opt
gv bytecomp byte-compile cconv cl-loaddefs cl-lib time-date mule-util
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded 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 dbusbind inotify lcms2 dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 462460 24851)
 (symbols 48 34148 1)
 (miscs 40 152 216)
 (strings 32 81423 1657)
 (string-bytes 1 2230165)
 (vectors 16 54878)
 (vector-slots 8 941076 8314)
 (floats 8 210 336)
 (intervals 56 354 0)
 (buffers 992 14))