From 9245d813c6f53e3c57b59feed4e43c4af3a3ea21 Mon Sep 17 00:00:00 2001
From: David Crawshaw <crawshaw@tailscale.com>
Date: Tue, 7 Mar 2023 13:09:58 -0500
Subject: [PATCH] tsnet: explicit message for panic seen in CI

Updates #7488

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
---
 tsnet/tsnet.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tsnet/tsnet.go b/tsnet/tsnet.go
index e021a55fa..ac685b9b4 100644
--- a/tsnet/tsnet.go
+++ b/tsnet/tsnet.go
@@ -214,7 +214,12 @@ func (s *Server) Loopback() (addr string, proxyCred, localAPICred string, err er
 		}()
 	}
 
-	return s.loopbackListener.Addr().String(), s.proxyCred, s.localAPICred, nil
+	lbAddr := s.loopbackListener.Addr()
+	if lbAddr == nil {
+		// https://github.com/tailscale/tailscale/issues/7488
+		panic("loopbackListener has no Addr")
+	}
+	return lbAddr.String(), s.proxyCred, s.localAPICred, nil
 }
 
 type localSecHandler struct {