Merge pull request #233 from kaleido-io/empty-bytes

Differentiate bytes vs. fixed bytes in encoding parameters

internal/eth/txn.go

@@ -654,7 +654,11 @@ func (tx *Txn) generateTypedArg(requiredType *ethbinding.ABIType, param interfac
 			return nil, errors.Errorf(errors.TransactionSendInputTypeBadJSONTypeForBytes, methodName, path, requiredType, suppliedType)
 		}
 		if len(bSlice) == 0 {
-			return [0]byte{}, nil
+			if requiredType.T == ethbinding.BytesTy {
+				return []byte{}, nil
+			} else {
+				return [0]byte{}, nil
+			}
 		} else if requiredType.GetType().Kind() == reflect.Array {
 			// Create ourselves an array of the right size (ethereum won't accept a slice)
 			bArrayType := reflect.ArrayOf(len(bSlice), reflect.TypeOf(bSlice[0]))

internal/eth/txn_test.go

@@ -1470,6 +1470,54 @@ func TestSendTxnPackError(t *testing.T) {
 	assert.Regexp("cannot use \\[0\\]uint8 as type \\[1\\]uint8 as argument", err.Error())
 }
 
+func TestSendTxnPackEmptyBytes(t *testing.T) {
+	assert := assert.New(t)
+
+	var msg messages.SendTransaction
+	msg.Parameters = []interface{}{"0x"}
+	msg.Method = &ethbinding.ABIElementMarshaling{
+		Name: "testFunc",
+		Inputs: []ethbinding.ABIArgumentMarshaling{
+			{
+				Name: "param1",
+				Type: "bytes",
+			},
+		},
+		Outputs: []ethbinding.ABIArgumentMarshaling{
+			{
+				Name: "ret1",
+				Type: "uint256",
+			},
+		},
+	}
+	_, err := NewSendTxn(&msg, nil)
+	assert.NoError(err)
+}
+
+func TestSendTxnPackBytes(t *testing.T) {
+	assert := assert.New(t)
+
+	var msg messages.SendTransaction
+	msg.Parameters = []interface{}{"0x1234"}
+	msg.Method = &ethbinding.ABIElementMarshaling{
+		Name: "testFunc",
+		Inputs: []ethbinding.ABIArgumentMarshaling{
+			{
+				Name: "param1",
+				Type: "bytes2",
+			},
+		},
+		Outputs: []ethbinding.ABIArgumentMarshaling{
+			{
+				Name: "ret1",
+				Type: "uint256",
+			},
+		},
+	}
+	_, err := NewSendTxn(&msg, nil)
+	assert.NoError(err)
+}
+
 func TestProcessRLPBytesValidTypes(t *testing.T) {
 	assert := assert.New(t)