Improve error message for git-filter-branch

Tell the user that a backup (original) already exists, and how to solve
this problem (with -f option)

Signed-off-by: John Tapsell <johnflux@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 9a09ba138244b1665de78e94ce12fb8fdb878758..20f6f5175070f62ab74eda4839c637afe1004d49 100755 (executable)
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -232,7 +232,9 @@ while read sha1 type name
 do
        case "$force,$name" in
        ,$orig_namespace*)
-               die "Namespace $orig_namespace not empty"
+               die "Cannot create a new backup.
+A previous backup already exists in $orig_namespace
+Force overwriting the backup with -f"
        ;;
        t,$orig_namespace*)
                git update-ref -d "$name" $sha1