consensus: assume non-nil message in decodeData

`nil` message is occuring only in tests to check that
no unnecessary decoding is done on errors.

pkg/consensus/payload.go

@@ -340,7 +340,7 @@ func (t messageType) String() string {
 
 // decode data of payload into it's message
 func (p *Payload) decodeData() error {
-	m := new(message)
+	m := p.message
 	br := io.NewBinReaderFromBuf(p.data)
 	m.DecodeBinary(br)
 	if br.Err != nil {

pkg/consensus/payload_test.go

@@ -102,6 +102,7 @@ func TestConsensusPayload_Serializable(t *testing.T) {
 		require.NoError(t, testserdes.DecodeBinary(data, actual))
 		// message is nil after decoding as we didn't yet call decodeData
 		require.Nil(t, actual.message)
+		actual.message = new(message)
 		// message should now be decoded from actual.data byte array
 		assert.NoError(t, actual.decodeData())
 		assert.NotNil(t, actual.MarshalUnsigned())
@@ -152,7 +153,7 @@ func TestConsensusPayload_DecodeBinaryInvalid(t *testing.T) {
 	buf[delimeterIndex] = 1
 	buf[lenIndex] = 34
 	buf[typeIndex] = byte(prepareResponseType)
-	p := new(Payload)
+	p := &Payload{message: new(message)}
 	require.NoError(t, testserdes.DecodeBinary(buf, p))
 	// decode `data` into `message`
 	_ = p.Hash()
@@ -161,7 +162,7 @@ func TestConsensusPayload_DecodeBinaryInvalid(t *testing.T) {
 
 	// invalid type
 	buf[typeIndex] = 0xFF
-	actual := new(Payload)
+	actual := &Payload{message: new(message)}
 	require.NoError(t, testserdes.DecodeBinary(buf, actual))
 	require.Error(t, actual.decodeData())
 

pkg/consensus/recovery_message_test.go

@@ -23,7 +23,6 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 
 	r := &recoveryMessage{}
 	p := NewPayload(netmode.UnitTestNet)
-	p.message = &message{}
 	p.SetType(payload.RecoveryMessageType)
 	p.SetPayload(r)
 	// sign payload to have verification script
@@ -35,7 +34,6 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 		transactionHashes: []util.Uint256{{1}},
 	}
 	p1 := NewPayload(netmode.UnitTestNet)
-	p1.message = &message{}
 	p1.SetType(payload.PrepareRequestType)
 	p1.SetPayload(req)
 	p1.SetValidatorIndex(0)
@@ -43,7 +41,6 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 
 	t.Run("prepare response is added", func(t *testing.T) {
 		p2 := NewPayload(netmode.UnitTestNet)
-		p2.message = &message{}
 		p2.SetType(payload.PrepareResponseType)
 		p2.SetPayload(&prepareResponse{
 			preparationHash: p1.Hash(),
@@ -80,7 +77,6 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 
 	t.Run("change view is added", func(t *testing.T) {
 		p3 := NewPayload(netmode.UnitTestNet)
-		p3.message = &message{}
 		p3.SetType(payload.ChangeViewType)
 		p3.SetPayload(&changeView{
 			newViewNumber: 1,
@@ -103,7 +99,6 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 
 	t.Run("commit is added", func(t *testing.T) {
 		p4 := NewPayload(netmode.UnitTestNet)
-		p4.message = &message{}
 		p4.SetType(payload.CommitType)
 		p4.SetPayload(randomMessage(t, commitType))
 		p4.SetValidatorIndex(3)