1 files changed, 4 insertions, 0 deletions
diff --git a/refs.c b/refs.c
index c9bcf148b0..39a3b23804 100644
--- a/refs.c
+++ b/refs.c
@@ -1412,6 +1412,10 @@ int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *
 	tz = strtoul(tz_c, NULL, 10);
 	if (get_sha1_hex(logdata, sha1))
 		die("Log %s is corrupt.", logfile);
+	if (is_null_sha1(sha1)) {
+		if (get_sha1_hex(logdata + 41, sha1))
+			die("Log %s is corrupt.", logfile);
+	}
 	if (msg)
 		*msg = ref_msg(logdata, logend);
 	munmap(log_mapped, mapsz);