[PATCH] Remove branch by putting a null sha1 into the ref file.

[Christian Couder <chriscool@tuxfamily.org>]

With the new packed ref file format from Linus, this should be
the new way to remove a branch.

"refs.c" is fixed so that a null sha1 for a deleted branch does
not result in "refs/head/deleted does not point to a valid
commit object!" messages.

"t/t3200-branch.sh" is fixed so that it uses git-show-ref
instead of checking that the ref does not exist when a branch
is deleted.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 git-branch.sh     |    6 +++++-
 refs.c            |    2 ++
 t/t3200-branch.sh |    2 +-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/git-branch.sh b/git-branch.sh
index 2600e9c..cb55880 100755
--- a/git-branch.sh
+++ b/git-branch.sh
@@ -10,6 +10,9 @@ SUBDIRECTORY_OK='Yes'
 
 headref=$(git-symbolic-ref HEAD | sed -e 's|^refs/heads/||')
 
+# Fourty 0s.
+NULL_SHA1="0000000000000000000000000000000000000000" 
+
 delete_branch () {
     option="$1"
     shift
@@ -43,7 +46,8 @@ If you are sure you want to delete it, r
 	    ;;
 	esac
 	rm -f "$GIT_DIR/logs/refs/heads/$branch_name"
-	rm -f "$GIT_DIR/refs/heads/$branch_name"
+	echo $NULL_SHA1 > "$GIT_DIR/refs/heads/$branch_name" || \
+	    die "Failed to delete branch '$branch_name' !"
 	echo "Deleted branch $branch_name."
     done
     exit 0
diff --git a/refs.c b/refs.c
index 5e65314..76d8d0e 100644
--- a/refs.c
+++ b/refs.c
@@ -162,6 +162,8 @@ static int do_for_each_ref(const char *b
 				error("%s points nowhere!", path);
 				continue;
 			}
+			if (is_null_sha1(sha1))
+				continue; /* Ignore deleted refs. */
 			if (!has_sha1_file(sha1)) {
 				error("%s does not point to a valid "
 				      "commit object!", path);
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 5b04efc..150dfdc 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -47,7 +47,7 @@ test_expect_success \
 test_expect_success \
     'git branch -d d/e/f should delete a branch and a log' \
 	'git-branch -d d/e/f &&
-	 test ! -f .git/refs/heads/d/e/f &&
+	 ! git-show-ref --verify --quiet -- "refs/heads/d/e/f" &&
 	 test ! -f .git/logs/refs/heads/d/e/f'
 
 cat >expect <<EOF
-- 
1.4.2.1.g4251-dirty