ref_transaction_verify(): new function to check a reference's value

diff --git a/builtin/commit.c b/builtin/commit.c
index 8afb0ff5e044719b1d2266231d1d2881e4d93f21..682f922c736dbaaa918a9f27c07487e3f15ec286 100644 (file)
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1766,7 +1766,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
        if (!transaction ||
            ref_transaction_update(transaction, "HEAD", sha1,
                                   current_head
-                                  ? current_head->object.sha1 : NULL,
+                                  ? current_head->object.sha1 : null_sha1,
                                   0, sb.buf, &err) ||
            ref_transaction_commit(transaction, &err)) {
                rollback_index_files();