caddytls: Check for nil ALPN; close #5470 (#5473)

* Check for nil ALPN; close #5470

* Apply patch

* Actually I want to try this

1 files changed, 2 insertions, 2 deletions

diff --git a/modules/caddytls/connpolicy.go b/modules/caddytls/connpolicy.go
index 46a8eda..a4dc411 100644
--- a/modules/caddytls/connpolicy.go
+++ b/modules/caddytls/connpolicy.go
@@ -54,7 +54,7 @@ func (cp ConnectionPolicies) Provision(ctx caddy.Context) error {
 		}
 
 		// enable HTTP/2 by default
-		if len(pol.ALPN) == 0 {
+		if pol.ALPN == nil {
 			pol.ALPN = append(pol.ALPN, defaultALPN...)
 		}
 
@@ -283,7 +283,7 @@ func (p *ConnectionPolicy) buildStandardTLSConfig(ctx caddy.Context) error {
 			break
 		}
 	}
-	if !alpnFound {
+	if !alpnFound && (cfg.NextProtos == nil || len(cfg.NextProtos) > 0) {
 		cfg.NextProtos = append(cfg.NextProtos, acmez.ACMETLS1Protocol)
 	}