test-reach: test reduce_heads

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 64f21547c1ab99ef3ad98d57fe0fbadff9621838..ccceaf19a74373bb23b2a2b1aa71b7f0bb909d54 100755 (executable)
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -11,6 +11,8 @@
 # The following functions will also be available in the commit filter:
 
 functions=$(cat << \EOF
+EMPTY_TREE=$(git hash-object -t tree /dev/null)
+
 warn () {
        echo "$*" >&2
 }
@@ -46,7 +48,7 @@ git_commit_non_empty_tree()
 {
        if test $# = 3 && test "$1" = $(git rev-parse "$3^{tree}"); then
                map "$3"
-       elif test $# = 1 && test "$1" = 4b825dc642cb6eb9a060e54bf8d69288fbee4904; then
+       elif test $# = 1 && test "$1" = $EMPTY_TREE; then
                :
        else
                git commit-tree "$@"