IssueTracker

Component used: Room
Version used: 1.1.1
Devices/Android versions reproduced on: Any (generated code)

public class Transaction {
...
    @Embedded
    private Money amount;

public class Payment extends Transaction {
...
    public Payment(@NonNull Long transactionId, @NonNull Date date, Money amount, String company, String notes,
                   @NonNull Long invoiceId, @NonNull PaymentMethod paymentMethod, Double cryptoAmount) {
        super(transactionId, date, amount, company, notes);

public class Shipment extends Transaction {
...
    public Shipment(@NonNull Long transactionId, @NonNull Date date, Money amount, String company, String notes,
                    @NonNull Long orderId, @NonNull ShipmentMethod shipmentMethod,
                    @NonNull String name, @NonNull String address, @NonNull String country,
                    String trackingNumber, String weight, String dimensions) {
        super(transactionId, date, amount, company, notes);

Generated code from Dao classes:

Fetching relation, OK:
            _item_1 = new Payment(_tmpTransactionId,_tmpDate,_tmpAmount,_tmpCompany,_tmpNotes,_tmpInvoiceId,_tmpPaymentMethod,_tmpCryptoAmount);

Fetching relation, not OK - 3rd argument is null even though _tmpAmount has been set:
            final Money _tmpAmount;
            if (! (_cursor.isNull(_cursorIndexOfCurrency) && _cursor.isNull(_cursorIndexOfExchangeRate) && _cursor.isNull(_cursorIndexOfAmount))) {
...
              _tmpAmount = new Money(_tmpCurrency,_tmpExchangeRate,_tmpAmount_1);
            }  else  {
              _tmpAmount = null;
            }
            _item_1 = new Shipment(_tmpTransactionId,_tmpDate,null,_tmpCompany,_tmpNotes,_tmpOrderId,_tmpShipmentMethod,_tmpName,_tmpAddress,_tmpCountry,_tmpTrackingNumber,_tmpWeight,_tmpDimensions);

Another case, from a @Query generated method:

        _result = new Shipment(_tmpTransactionId,_tmpDate,null,_tmpCompany,_tmpNotes,_tmpOrderId,_tmpShipmentMethod,_tmpName,_tmpAddress,_tmpCountry,_tmpTrackingNumber,_tmpWeight,_tmpDimensions);

Using trial and error, I found that creating another class Transaction2 that is an exact copy of Transaction, and having Shipment extend from it:

public class Shipment extends Transaction2 {

works around the problem:

            _item_1 = new Shipment(_tmpTransactionId,_tmpDate,_tmpAmount,_tmpCompany,_tmpNotes,_tmpOrderId,_tmpShipmentMethod,_tmpName,_tmpAddress,_tmpCountry,_tmpTrackingNumber,_tmpWeight,_tmpDimensions);

        _result = new Shipment(_tmpTransactionId,_tmpDate,_tmpAmount,_tmpCompany,_tmpNotes,_tmpOrderId,_tmpShipmentMethod,_tmpName,_tmpAddress,_tmpCountry,_tmpTrackingNumber,_tmpWeight,_tmpDimensions);

My hypothesis is that since Shipment is lexically after Payment, the Room compiler handles Payment correctly, but not Shipment.