[qt] Return useful error message on ATMP failure

src/qt/sendcoinsdialog.cpp

@@ -534,7 +534,7 @@ void SendCoinsDialog::processSendCoinsReturn(const WalletModel::SendCoinsReturn
         msgParams.second = CClientUIInterface::MSG_ERROR;
         break;
     case WalletModel::TransactionCommitFailed:
-        msgParams.first = tr("The transaction was rejected! This might happen if some of the coins in your wallet were already spent, such as if you used a copy of wallet.dat and coins were spent in the copy but not marked as spent here.");
+        msgParams.first = tr("The transaction was rejected with the following reason: %1").arg(sendCoinsReturn.reasonCommitFailed);
         msgParams.second = CClientUIInterface::MSG_ERROR;
         break;
     case WalletModel::AbsurdFee:

src/qt/walletmodel.cpp

@@ -331,7 +331,7 @@ WalletModel::SendCoinsReturn WalletModel::sendCoins(WalletModelTransaction &tran
         CReserveKey *keyChange = transaction.getPossibleKeyChange();
         CValidationState state;
         if(!wallet->CommitTransaction(*newTx, *keyChange, g_connman.get(), state))
-            return TransactionCommitFailed;
+            return SendCoinsReturn(TransactionCommitFailed, QString::fromStdString(state.GetRejectReason()));
 
         CTransaction* t = (CTransaction*)newTx;
         CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);

src/qt/walletmodel.h

@@ -144,9 +144,13 @@ public:
     // Return status record for SendCoins, contains error id + information
     struct SendCoinsReturn
     {
-        SendCoinsReturn(StatusCode _status = OK):
-            status(_status) {}
+        SendCoinsReturn(StatusCode _status = OK, QString _reasonCommitFailed = "")
+            : status(_status),
+              reasonCommitFailed(_reasonCommitFailed)
+        {
+        }
         StatusCode status;
+        QString reasonCommitFailed;
     };
 
     // prepare transaction for getting txfee before sending coins