Add Transaction.RemoveSignatures()

Author: NicolasDorier

NBitcoin/BIP174/PSBT0.cs

@@ -28,11 +28,7 @@ private static Maps CreateMap(Transaction transaction, Network network)
 		var maps = new Maps();
 		var global = maps.NewMap();
 		var noSigTx = transaction.Clone();
-		foreach (var input in noSigTx.Inputs)
-		{
-			input.ScriptSig = Script.Empty;
-			input.WitScript = WitScript.Empty;
-		}
+		noSigTx.RemoveSignatures();
 		global.Add([PSBTConstants.PSBT_GLOBAL_UNSIGNED_TX], noSigTx.ToBytes());
 		foreach (var input in transaction.Inputs)
 		{

NBitcoin/Transaction.cs

@@ -339,6 +339,12 @@ public static TxIn CreateCoinbase(int height)
 			txin.ScriptSig = new Script(Op.GetPushOp(height)) + OpcodeType.OP_0;
 			return txin;
 		}
+
+		public void RemoveSignatures()
+		{
+			ScriptSig = Script.Empty;
+			WitScript = WitScript.Empty;
+		}
 	}
 
 	public class TxOutCompressor : IBitcoinSerializable
@@ -1445,6 +1451,12 @@ public static Transaction Parse(string hex, Network network)
 			return Load(Encoders.Hex.DecodeData(hex), network);
 		}
 
+		public void RemoveSignatures()
+		{
+			foreach (var input in Inputs)
+				input.RemoveSignatures();
+		}
+
 		public static bool TryParse(string hex, Network network, out Transaction transaction)
 		{
 			if (hex == null)

NBitcoin/TransactionBuilder.cs

@@ -15,6 +15,7 @@
 using System.Net.Http.Headers;
 using System.Text.RegularExpressions;
 using System.Diagnostics.CodeAnalysis;
+using NBitcoin.Scripting.Parser;
 
 namespace NBitcoin
 {
@@ -490,19 +491,11 @@ public TransactionSigningContext(TransactionBuilder builder, Transaction transac
 
 			private static Transaction RemoveSigs(Transaction tx)
 			{
-				Transaction? clone = null;
-				for (int i = 0; i < tx.Inputs.Count; i++)
-				{
-					var input = tx.Inputs[i];
-					if (!WitScript.IsNullOrEmpty(input.WitScript) || !Script.IsNullOrEmpty(input.ScriptSig))
-					{
-						clone ??= tx.Clone();
-						input = clone.Inputs[i];
-						input.WitScript = WitScript.Empty;
-						input.ScriptSig = Script.Empty;
-					}
-				}
-				return clone ?? tx;
+				var hasSig = tx.Inputs.Any(input => !WitScript.IsNullOrEmpty(input.WitScript) || !Script.IsNullOrEmpty(input.ScriptSig));
+				if (!hasSig)
+					return tx;
+				tx = tx.Clone();
+				return tx;
 			}
 
 			public TransactionSigningContext(TransactionBuilder builder, PSBT psbt, Transaction? transaction, SigningOptions signingOptions)