ignore QUICConn.SendSessionTicket error if session tickets are disabled (#4030)

internal/handshake/crypto_setup.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -356,10 +357,15 @@ func (h *cryptoSetup) getDataForSessionTicket() []byte {
 // Due to limitations in crypto/tls, it's only possible to generate a single session ticket per connection.
 // It is only valid for the server.
 func (h *cryptoSetup) GetSessionTicket() ([]byte, error) {
-	if h.tlsConf.SessionTicketsDisabled {
-		return nil, nil
-	}
 	if err := qtls.SendSessionTicket(h.conn, h.allow0RTT); err != nil {
+		// Session tickets might be disabled by tls.Config.SessionTicketsDisabled.
+		// We can't check h.tlsConfig here, since the actual config might have been obtained from
+		// the GetConfigForClient callback.
+		// See https://github.com/golang/go/issues/62032.
+		// Once that issue is resolved, this error assertion can be removed.
+		if strings.Contains(err.Error(), "session ticket keys unavailable") {
+			return nil, nil
+		}
 		return nil, err
 	}
 	ev := h.conn.NextEvent()