vc-test.sh

#!/bin/sh

# Your challenge: figure out why the "sleep-for" in the emacs lisp
# below seems to return in far less than five seconds

EMACS=/usr/local/src/emacs-with-my-tweaks.git/src/emacs

cd /tmp
rm -rf xyzzy test-output

mkdir xyzzy
cd xyzzy
git init
mkdir Jack Jill
touch Jack/it Jill/it
git add .
git commit -m "golly!"
echo More stuff >> Jack/it
cd Jill

git status

cat > /tmp/test.el <<EOF

(defvar *dir* "/tmp/xyzzy/Jill"
  "Directory in which we will run a test of vc-dir")
(cd *dir*)
(condition-case error
    (progn
      (vc-dir *dir*)
      ;; Apparently, vc-dir updates its buffer asynchronously, so we
      ;; have to sleep for a little while after calling it, but before
      ;; taking a snapshot of the vc-dir buffer -- lest that buffer be
      ;; incorrect.
      (sleep-for 5)
      (write-region (point-min) (point-max)  "/tmp/test-output")
      (message "Life is good, apparently")
      (kill-emacs 0))
  (error
   (message "Got us an error: %s" error)
   (kill-emacs 1)))

EOF

$EMACS --batch --load /tmp/test.el

echo "============================="

cat /tmp/test-output

what-I-see

$ time sh -x /usr/local/src/vc-git-exploration/vc-test.sh 
+ EMACS=/usr/local/src/emacs-with-my-tweaks.git/src/emacs
+ cd /tmp
+ rm -rf xyzzy test-output
+ mkdir xyzzy
+ cd xyzzy
+ git init
Initialized empty Git repository in /tmp/xyzzy/.git/
+ mkdir Jack Jill
+ touch Jack/it Jill/it
+ git add .
+ git commit -m golly!
[master (root-commit)]: created c07f664: "golly!"
 0 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 Jack/it
 create mode 100644 Jill/it
+ echo More stuff
+ cd Jill
+ git status
# On branch master
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#	modified:   ../Jack/it
#
no changes added to commit (use "git add" and/or "git commit -a")
+ cat
+ /usr/local/src/emacs-with-my-tweaks.git/src/emacs --batch --load /tmp/test.el
Wrote /tmp/test-output
Life is good, apparently
+ echo =============================
=============================
+ cat /tmp/test-output
VC backend : Git
Working dir: /tmp/xyzzy/Jill/
Branch     : master



real	0m0.306s
user	0m0.220s
sys	0m0.096s