From 691f1d5c1dd43de88ba590dfd3df84a77a3871cb Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Mon, 19 Oct 2020 20:18:31 -0700
Subject: [PATCH] types/flagtype: fix bug showing the default port value (shown
 in --help)

---
 types/flagtype/flagtype.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/types/flagtype/flagtype.go b/types/flagtype/flagtype.go
index ceab09869..6b97a2902 100644
--- a/types/flagtype/flagtype.go
+++ b/types/flagtype/flagtype.go
@@ -21,7 +21,12 @@ func PortValue(dst *uint16, defaultPort uint16) flag.Value {
 	return portValue{dst}
 }
 
-func (p portValue) String() string { return fmt.Sprint(p.n) }
+func (p portValue) String() string {
+	if p.n == nil {
+		return ""
+	}
+	return fmt.Sprint(*p.n)
+}
 func (p portValue) Set(v string) error {
 	if v == "" {
 		return errors.New("can't be the empty string")