Allow Transactions without inputs to always be cloned and serialized if segwit not supported. (#1282)

Author: NicolasDorier

.github/workflows/CI.yml

@@ -13,6 +13,7 @@ jobs:
       - uses: actions/checkout@v2
       - run: ./Build/CI/install-env.sh
         env:
+          DOTNET_INSTALL_DIR: /usr/share/dotnet
           ADDITIONAL_RUNTIME: 6.0.36
       - run: ./Build/CI/tests.sh
         env:
@@ -29,6 +30,7 @@ jobs:
           sudo dpkg -i libssl1.0.0_1.0.2n-1ubuntu5_amd64.deb
       - run: ./Build/CI/install-env.sh
         env:
+          DOTNET_INSTALL_DIR: /usr/share/dotnet
           ADDITIONAL_RUNTIME: 3.1.32
       - run: ./Build/CI/tests.sh
         env:
@@ -43,6 +45,7 @@ jobs:
       - uses: actions/checkout@v2
       - run: ./Build/CI/install-env.sh
         env:
+          DOTNET_INSTALL_DIR: /usr/share/dotnet
           ADDITIONAL_RUNTIME: 6.0.36
       - run: ./Build/CI/tests.sh
         env:

Build/CI/install-env.sh

@@ -15,3 +15,4 @@ chmod +x ./dotnet-install.sh
 [[ "${ADDITIONAL_RUNTIME:-}" ]] \
     && echo "Additional Runtime needed: $ADDITIONAL_RUNTIME" \
     && ./dotnet-install.sh --version "$ADDITIONAL_RUNTIME" --runtime dotnet --channel LTS
+

Build/CI/tests.sh

@@ -7,6 +7,7 @@ export PATH="$PATH:$HOME/.dotnet"
 
 export DOTNET_SYSTEM_GLOBALIZATION_INVARIANT=1
 dotnet --info
+
 dotnet build ./NBitcoin.Tests/NBitcoin.Tests.csproj \
              $BUILD_ARGS \
              -c Release \

NBitcoin.Altcoins/Dogecoin.cs

@@ -46,6 +46,14 @@ public override TxOut CreateTxOut()
 			{
 				return new DogeTxOut();
 			}
+
+			public override ProtocolCapabilities GetProtocolCapabilities(uint protocolVersion)
+			{
+				var capabilities = base.GetProtocolCapabilities(protocolVersion);
+				capabilities.SupportWitness = false;
+				return capabilities;
+			}
+
 			protected override TransactionBuilder CreateTransactionBuilderCore(Network network)
 			{
 				// https://github.com/dogecoin/dogecoin/blob/master/doc/fee-recommendation.md

NBitcoin.Tests/transaction_tests.cs

@@ -845,8 +845,8 @@ Transaction BuildTransaction(bool checkFee = true)
 						return tx;
 					};
 					Transaction tx;
-					
-					
+
+
 					if (dustPrevention)
 					{
 						feeAmount = scriptCoin2.Amount - dust + Money.Satoshis(1);
@@ -3086,6 +3086,26 @@ public void witnessHasPushSizeLimit()
 			Assert.Equal(ScriptError.PushSize, error);
 		}
 
+		[Fact]
+		[Trait("UnitTest", "UnitTest")]
+		public void CanParseCloneTxWithoutInput()
+		{
+			var tx = Transaction.Create(Dogecoin.Instance.Mainnet);
+			for (int i = 0; i < 5; i++)
+			{
+				tx.Outputs.Add(new TxOut(Money.Satoshis(500), new Key()));
+			}
+			tx.Clone();
+			var psbt = PSBT.FromTransaction(tx, Dogecoin.Instance.Mainnet);
+
+			tx = Transaction.Create(Network.Main);
+			for (int i = 0; i < 5; i++)
+			{
+				tx.Outputs.Add(new TxOut(Money.Satoshis(500), new Key()));
+			}
+			tx.Clone();
+		}
+
 		[Fact]
 		[Trait("UnitTest", "UnitTest")]
 		//http://brainwallet.org/#tx

NBitcoin/BitcoinStream.cs

@@ -164,7 +164,7 @@ public ConsensusFactory ConsensusFactory
 			get
 			{
 
-				return _ConsensusFactory ??=  Consensus.Main.ConsensusFactory;;
+				return _ConsensusFactory ??=  Consensus.Main.ConsensusFactory;
 			}
 			set
 			{

NBitcoin/IBitcoinSerializable.cs

@@ -78,9 +78,12 @@ public static void FromBytes(this IBitcoinSerializable serializable, byte[] byte
 		public static byte[] ToBytes(this IBitcoinSerializable serializable, uint? version = null)
 		{
 			MemoryStream ms = new MemoryStream();
+			var consensusFactory =
+				(serializable as Transaction)?.GetConsensusFactory() ?? Consensus.Main.ConsensusFactory;
 			serializable.ReadWrite(new BitcoinStream(ms, true)
 			{
-				ProtocolVersion = version
+				ProtocolVersion = version,
+				ConsensusFactory = consensusFactory
 			});
 			return ToArrayEfficient(ms);
 		}

NBitcoin/Transaction.cs

@@ -1585,7 +1585,7 @@ public virtual void ReadWrite(BitcoinStream stream)
 			}
 			else
 			{
-				if (Inputs.Count == 0 && !stream.AllowNoInputs)
+				if (Inputs.Count == 0 && !stream.AllowNoInputs && witSupported)
 					throw new InvalidOperationException("The transaction must have at least one input");
 				stream.ReadWrite(ref nVersion);
 
@@ -1679,7 +1679,22 @@ public void PrecomputeHash(bool invalidateExisting, bool lazily)
 		public Transaction Clone(bool cloneCache)
 		{
 			var clone = GetConsensusFactory().CreateTransaction();
-			clone.ReadWrite(this.ToBytes(), GetConsensusFactory());
+			MemoryStream ms = new MemoryStream();
+			var txOptions = this.Inputs.Count is 0 ? TransactionOptions.None : TransactionOptions.All;
+			var stream = new BitcoinStream(ms, true)
+			{
+				TransactionOptions = txOptions,
+				ConsensusFactory = GetConsensusFactory(),
+				AllowNoInputs = true
+			};
+			this.ReadWrite(stream);
+			ms.Position = 0;
+			stream = new BitcoinStream(ms, false)
+			{
+				TransactionOptions = txOptions,
+				ConsensusFactory = GetConsensusFactory()
+			};
+			clone.ReadWrite(stream);
 			if (cloneCache)
 				clone._Hashes = _Hashes.ToArray();
 			return clone;
@@ -2463,11 +2478,7 @@ public virtual ConsensusFactory GetConsensusFactory()
 		}
 
 		public Transaction Clone()
-		{
-			var instance = GetConsensusFactory().CreateTransaction();
-			instance.ReadWrite(new BitcoinStream(this.ToBytes()) { ConsensusFactory = GetConsensusFactory() });
-			return instance;
-		}
+			=> Clone(false);
 
 		public void FromBytes(byte[] bytes)
 		{