fix(network): fix inconsistent typed value issue in DelegatePacketPro…

…xy (#35)

`atomic.Value` doesn't accept values with different `struct` types (even if you cast the value to the same interface). So I use `atomic.Pointer[]` instead.

network/delegate_packet_proxy.go

@@ -41,7 +41,10 @@ var errInvalidProxy = errors.New("the underlying proxy must not be nil")
 var _ DelegatePacketProxy = (*delegatePacketProxy)(nil)
 
 type delegatePacketProxy struct {
-	proxy atomic.Value
+	// The underlying PacketProxy when create NewSession.
+	// Note that we must not use atomic.Value; otherwise TestSetProxyOfDifferentTypes will panic with
+	// "store inconsistently typed value".
+	proxy atomic.Pointer[PacketProxy]
 }
 
 // NewDelegatePacketProxy creates a new [DelegatePacketProxy] that forwards calls to the `proxy` [PacketProxy].
@@ -51,20 +54,20 @@ func NewDelegatePacketProxy(proxy PacketProxy) (DelegatePacketProxy, error) {
 		return nil, errInvalidProxy
 	}
 	dp := delegatePacketProxy{}
-	dp.proxy.Store(proxy)
+	dp.proxy.Store(&proxy)
 	return &dp, nil
 }
 
 // NewSession implements PacketProxy.NewSession, and it will forward the call to the underlying PacketProxy.
 func (p *delegatePacketProxy) NewSession(respWriter PacketResponseReceiver) (PacketRequestSender, error) {
-	return p.proxy.Load().(PacketProxy).NewSession(respWriter)
+	return (*p.proxy.Load()).NewSession(respWriter)
 }
 
 // SetProxy implements DelegatePacketProxy.SetProxy.
 func (p *delegatePacketProxy) SetProxy(proxy PacketProxy) error {
 	if proxy == nil {
 		return errInvalidProxy
 	}
-	p.proxy.Store(proxy)
+	p.proxy.Store(&proxy)
 	return nil
 }

network/delegate_packet_proxy_test.go

@@ -125,6 +125,26 @@ func TestSetProxyWithNilValue(t *testing.T) {
 	require.Error(t, err)
 }
 
+// Make sure we can SetProxy to different types
+func TestSetProxyOfDifferentTypes(t *testing.T) {
+	defProxy := &sessionCountPacketProxy{}
+	newProxy := &noopPacketProxy{}
+
+	p, err := NewDelegatePacketProxy(defProxy)
+	require.NotNil(t, p)
+	require.NoError(t, err)
+
+	// SetProxy should not return error
+	err = p.SetProxy(newProxy)
+	require.NoError(t, err)
+
+	// NewSession' should not go to defProxy
+	snd, err := p.NewSession(nil)
+	require.Nil(t, snd)
+	require.NoError(t, err)
+	require.Exactly(t, 0, defProxy.Count())
+}
+
 // sessionCountPacketProxy logs the count of the NewSession calls, and returns a nil PacketRequestSender
 type sessionCountPacketProxy struct {
 	cnt atomic.Int32
@@ -138,3 +158,10 @@ func (sp *sessionCountPacketProxy) NewSession(respWriter PacketResponseReceiver)
 func (sp *sessionCountPacketProxy) Count() int {
 	return int(sp.cnt.Load())
 }
+
+type noopPacketProxy struct {
+}
+
+func (noopPacketProxy) NewSession(PacketResponseReceiver) (PacketRequestSender, error) {
+	return nil, nil
+}