copy the GetLogWriter callback when populating a quic.Config

client.go

@@ -248,16 +248,6 @@ func newClient(
 	return c, nil
 }
 
-// populateClientConfig populates fields in the quic.Config with their default values, if none are set
-// it may be called with nil
-func populateClientConfig(config *Config, createdPacketConn bool) *Config {
-	config = populateConfig(config)
-	if config.ConnectionIDLength == 0 && !createdPacketConn {
-		config.ConnectionIDLength = protocol.DefaultConnectionIDLength
-	}
-	return config
-}
-
 func (c *client) dial(ctx context.Context, qlogger qlog.Tracer) error {
 	c.logger.Infof("Starting new connection to %s (%s -> %s), source connection ID %s, destination connection ID %s, version %s", c.tlsConf.ServerName, c.conn.LocalAddr(), c.conn.RemoteAddr(), c.srcConnID, c.destConnID, c.version)
 	if qlogger != nil {

config.go

@@ -21,6 +21,16 @@ func populateServerConfig(config *Config) *Config {
 	return config
 }
 
+// populateClientConfig populates fields in the quic.Config with their default values, if none are set
+// it may be called with nil
+func populateClientConfig(config *Config, createdPacketConn bool) *Config {
+	config = populateConfig(config)
+	if config.ConnectionIDLength == 0 && !createdPacketConn {
+		config.ConnectionIDLength = protocol.DefaultConnectionIDLength
+	}
+	return config
+}
+
 func populateConfig(config *Config) *Config {
 	if config == nil {
 		config = &Config{}
@@ -72,5 +82,6 @@ func populateConfig(config *Config) *Config {
 		StatelessResetKey:                     config.StatelessResetKey,
 		TokenStore:                            config.TokenStore,
 		QuicTracer:                            config.QuicTracer,
+		GetLogWriter:                          config.GetLogWriter,
 	}
 }

config_test.go

@@ -7,6 +7,7 @@ import (
 	"reflect"
 	"time"
 
+	"github.com/lucas-clemente/quic-go/internal/protocol"
 	"github.com/lucas-clemente/quic-go/quictrace"
 
 	. "github.com/onsi/ginkgo"
@@ -14,22 +15,9 @@ import (
 )
 
 var _ = Describe("Config", func() {
-	It("clones function fields", func() {
+	configWithNonZeroNonFunctionFields := func() *Config {
-		var calledAcceptToken, calledGetLogWriter bool
+		c := &Config{}
-		c1 := &Config{
+		v := reflect.ValueOf(c).Elem()
-			AcceptToken:  func(_ net.Addr, _ *Token) bool { calledAcceptToken = true; return true },
-			GetLogWriter: func(connectionID []byte) io.WriteCloser { calledGetLogWriter = true; return nil },
-		}
-		c2 := c1.Clone()
-		c2.AcceptToken(&net.UDPAddr{}, &Token{})
-		c2.GetLogWriter([]byte{1, 2, 3})
-		Expect(calledAcceptToken).To(BeTrue())
-		Expect(calledGetLogWriter).To(BeTrue())
-	})
-
-	It("clones non-function fields", func() {
-		c1 := &Config{}
-		v := reflect.ValueOf(c1).Elem()
 
 		typ := v.Type()
 		for i := 0; i < typ.NumField(); i++ {
@@ -70,8 +58,25 @@ var _ = Describe("Config", func() {
 				Fail(fmt.Sprintf("all fields must be accounted for, but saw unknown field %q", fn))
 			}
 		}
+		return c
+	}
+	Context("cloning", func() {
+		It("clones function fields", func() {
+			var calledAcceptToken, calledGetLogWriter bool
+			c1 := &Config{
+				AcceptToken:  func(_ net.Addr, _ *Token) bool { calledAcceptToken = true; return true },
+				GetLogWriter: func(connectionID []byte) io.WriteCloser { calledGetLogWriter = true; return nil },
+			}
+			c2 := c1.Clone()
+			c2.AcceptToken(&net.UDPAddr{}, &Token{})
+			c2.GetLogWriter([]byte{1, 2, 3})
+			Expect(calledAcceptToken).To(BeTrue())
+			Expect(calledGetLogWriter).To(BeTrue())
+		})
 
-		Expect(c1.Clone()).To(Equal(c1))
+		It("clones non-function fields", func() {
+			c := configWithNonZeroNonFunctionFields()
+			Expect(c.Clone()).To(Equal(c))
 		})
 
 		It("returns a copy", func() {
@@ -87,3 +92,50 @@ var _ = Describe("Config", func() {
 			Expect(c1.AcceptToken(&net.UDPAddr{}, nil)).To(BeTrue())
 		})
 	})
+
+	Context("populating", func() {
+		It("populates function fields", func() {
+			var calledAcceptToken, calledGetLogWriter bool
+			c1 := &Config{
+				AcceptToken:  func(_ net.Addr, _ *Token) bool { calledAcceptToken = true; return true },
+				GetLogWriter: func(connectionID []byte) io.WriteCloser { calledGetLogWriter = true; return nil },
+			}
+			c2 := populateConfig(c1)
+			c2.AcceptToken(&net.UDPAddr{}, &Token{})
+			c2.GetLogWriter([]byte{1, 2, 3})
+			Expect(calledAcceptToken).To(BeTrue())
+			Expect(calledGetLogWriter).To(BeTrue())
+		})
+
+		It("copies non-function fields", func() {
+			c := configWithNonZeroNonFunctionFields()
+			Expect(populateConfig(c)).To(Equal(c))
+		})
+
+		It("populates empty fields with default values", func() {
+			c := populateConfig(&Config{})
+			Expect(c.Versions).To(Equal(protocol.SupportedVersions))
+			Expect(c.HandshakeTimeout).To(Equal(protocol.DefaultHandshakeTimeout))
+			Expect(c.MaxReceiveStreamFlowControlWindow).To(BeEquivalentTo(protocol.DefaultMaxReceiveStreamFlowControlWindow))
+			Expect(c.MaxReceiveConnectionFlowControlWindow).To(BeEquivalentTo(protocol.DefaultMaxReceiveConnectionFlowControlWindow))
+			Expect(c.MaxIncomingStreams).To(Equal(protocol.DefaultMaxIncomingStreams))
+			Expect(c.MaxIncomingUniStreams).To(Equal(protocol.DefaultMaxIncomingUniStreams))
+		})
+
+		It("populates empty fields with default values, for the server", func() {
+			c := populateServerConfig(&Config{})
+			Expect(c.ConnectionIDLength).To(Equal(protocol.DefaultConnectionIDLength))
+			Expect(c.AcceptToken).ToNot(BeNil())
+		})
+
+		It("sets a default connection ID length if we didn't create the conn, for the client", func() {
+			c := populateClientConfig(&Config{}, false)
+			Expect(c.ConnectionIDLength).To(Equal(protocol.DefaultConnectionIDLength))
+		})
+
+		It("doesn't set a default connection ID length if we created the conn, for the client", func() {
+			c := populateClientConfig(&Config{}, true)
+			Expect(c.ConnectionIDLength).To(BeZero())
+		})
+	})
+})