[Wallet] Prevent user from paying a non-sense fee

src/wallet.cpp

@@ -1633,6 +1633,9 @@ CAmount CWallet::GetMinimumFee(unsigned int nTxBytes, unsigned int nConfirmTarge
 {
     // payTxFee is user-set "I want to pay this much"
     CAmount nFeeNeeded = payTxFee.GetFee(nTxBytes);
+    // prevent user from paying a non-sense fee (like 1 satoshi): 0 < fee < minRelayFee
+    if (nFeeNeeded > 0 && nFeeNeeded < ::minRelayTxFee.GetFee(nTxBytes))
+        nFeeNeeded = ::minRelayTxFee.GetFee(nTxBytes);
     // User didn't set: use -txconfirmtarget to estimate...
     if (nFeeNeeded == 0)
         nFeeNeeded = pool.estimateFee(nConfirmTarget).GetFee(nTxBytes);