From 3e2a7de2e9d10cfa0fcda9d58c2dfbde3cb3ca36 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Tue, 14 Sep 2021 09:00:04 -0700
Subject: [PATCH] tailcfg: don't panic on clone of nil RegisterRequest

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
---
 tailcfg/tailcfg.go      | 3 +++
 tailcfg/tailcfg_test.go | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/tailcfg/tailcfg.go b/tailcfg/tailcfg.go
index 4e22afd33..1df4cf388 100644
--- a/tailcfg/tailcfg.go
+++ b/tailcfg/tailcfg.go
@@ -635,6 +635,9 @@ type RegisterRequest struct {
 //
 // TODO: extend cmd/cloner to generate this method.
 func (req *RegisterRequest) Clone() *RegisterRequest {
+	if req == nil {
+		return nil
+	}
 	res := new(RegisterRequest)
 	*res = *req
 	if res.Hostinfo != nil {
diff --git a/tailcfg/tailcfg_test.go b/tailcfg/tailcfg_test.go
index f5fa60642..4cc987265 100644
--- a/tailcfg/tailcfg_test.go
+++ b/tailcfg/tailcfg_test.go
@@ -546,3 +546,11 @@ func TestDiscoKeyAppend(t *testing.T) {
 		t.Errorf("got %q; want %q", got, want)
 	}
 }
+
+func TestRegisterRequestNilClone(t *testing.T) {
+	var nilReq *RegisterRequest
+	got := nilReq.Clone()
+	if got != nil {
+		t.Errorf("got = %v; want nil", got)
+	}
+}