cvsexportcommit: introduce -W for shared working trees (between Git and CVS)

If you have a CVS checkout, it is easy to import the CVS history by
calling "git cvsimport".  However, interacting with the CVS repository
using "git cvsexportcommit" was cumbersome, since that script assumes
separate working directories for Git and CVS.

Now, you can call cvsexportcommit with the -W option.  This will
automatically discover the GIT_DIR, and it will check out the parent
commit before exporting the commit.

The intended workflow is this:

$ CVSROOT=$URL cvs co module
$ cd module
$ git cvsimport
hack, hack, hack, making two commits, cleaning them up using rebase -i.
$ git cvsexportcommit -W -c -p -u HEAD^
$ git cvsexportcommit -W -c -p -u HEAD

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/t/t9200-git-cvsexportcommit.sh b/t/t9200-git-cvsexportcommit.sh
index 42b144b1b3..b1dc32d056 100755
--- a/t/t9200-git-cvsexportcommit.sh
+++ b/t/t9200-git-cvsexportcommit.sh
@@ -297,4 +297,21 @@ test_expect_success 'commit a file with leading spaces in the name' '
 
 '
 
+test_expect_success 'use the same checkout for Git and CVS' '
+
+	(mkdir shared &&
+	 cd shared &&
+	 unset GIT_DIR &&
+	 cvs co . &&
+	 git init &&
+	 git add " space" &&
+	 git commit -m "fake initial commit" &&
+	 echo Hello >> " space" &&
+	 git commit -m "Another change" " space" &&
+	 git cvsexportcommit -W -p -u -c HEAD &&
+	 grep Hello " space" &&
+	 git diff-files)
+
+'
+
 test_done