handle adding non witness inputs to segwit transactions

src/main/java/com/sparrowwallet/drongo/protocol/Transaction.java

@@ -307,8 +307,12 @@ public class Transaction extends ChildMessage {
     }
 
     public TransactionInput addInput(Sha256Hash spendTxHash, long outputIndex, Script script) {
+        if(isSegwit()) {
+            return addInput(spendTxHash, outputIndex, script, new TransactionWitness(this));
+        } else {
             return addInput(new TransactionInput(this, new TransactionOutPoint(spendTxHash, outputIndex), script.getProgram()));
         }
+    }
 
     public TransactionInput addInput(Sha256Hash spendTxHash, long outputIndex, Script script, TransactionWitness witness) {
         if(!isSegwit()) {

src/main/java/com/sparrowwallet/drongo/protocol/TransactionWitness.java

@@ -33,6 +33,10 @@ public class TransactionWitness extends ChildMessage {
         pushes.add(witnessScript.getProgram());
     }
 
+    public TransactionWitness(Transaction transaction) {
+        this(transaction, new ArrayList<>());
+    }
+
     public TransactionWitness(Transaction transaction, List<byte[]> witnesses) {
         setParent(transaction);
         this.pushes = witnesses;

src/main/java/com/sparrowwallet/drongo/psbt/PSBT.java

@@ -484,7 +484,7 @@ public class PSBT {
                 if(psbtInput.getFinalScriptWitness() != null) {
                     txInput.setWitness(psbtInput.getFinalScriptWitness());
                 } else {
-                    txInput.setWitness(new TransactionWitness(transaction, Collections.emptyList()));
+                    txInput.setWitness(new TransactionWitness(transaction));
                 }
             }
         }