diff -urdpNX /usr/share/dontdiff dovecot-1.0-test55.vanilla/src/auth/mech.c dovecot-1.0-test55/src/auth/mech.c
--- dovecot-1.0-test55.vanilla/src/auth/mech.c	2004-12-04 18:07:56.000000000 +0300
+++ dovecot-1.0-test55/src/auth/mech.c	2004-12-04 18:14:01.000000000 +0300
@@ -258,7 +258,8 @@ void auth_request_extra_finish(struct au
 
 	if (passdb_cache != NULL && cache_key != NULL) {
 		str = t_str_new(64);
-		str_append_str(str, extra->str);
+		if (extra->str != NULL)
+			str_append_str(str, extra->str);
 		if (extra->request->no_failure_delay) {
 			if (str_len(str) > 0)
 				str_append_c(str, '\t');
@@ -266,7 +267,8 @@ void auth_request_extra_finish(struct au
 		}
 		auth_cache_insert(passdb_cache, extra->request, cache_key,
 				  t_strconcat(extra->password == NULL ? "" :
-					      extra->password, "\t",
+					      extra->password,
+					      str_len(str) > 0 ? "\t" : "",
 					      str_c(str), NULL));
 	}