fix empty bytes object construction

Author: irmen

dotnet/Razorvine.Pickle/Benchmarks/Benchmarks.csproj

@@ -7,8 +7,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.13.1" />
-    <PackageReference Include="BenchmarkDotNet.Diagnostics.Windows" Version="0.11.5" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.13.5" />
+    <PackageReference Include="BenchmarkDotNet.Diagnostics.Windows" Version="0.13.5" />
   </ItemGroup>
 
   <ItemGroup>

dotnet/Razorvine.Pickle/Pickle/Pickle.csproj

@@ -8,9 +8,9 @@
     <Authors>Irmen de Jong</Authors>
     <Product>Python pickle serialization protocol library for .NET</Product>
     <PackageId>Razorvine.Pickle</PackageId>
-    <Version>1.3.0</Version>
-    <AssemblyVersion>1.3.0.0</AssemblyVersion>
-    <FileVersion>1.3.0.0</FileVersion>
+    <Version>1.4.0</Version>
+    <AssemblyVersion>1.4.0.0</AssemblyVersion>
+    <FileVersion>1.4.0.0</FileVersion>
     <SignAssembly>true</SignAssembly>
     <DelaySign>false</DelaySign>
     <AssemblyOriginatorKeyFile>Pickle.snk</AssemblyOriginatorKeyFile>
@@ -25,6 +25,6 @@
     <PackageReleaseNotes>Stand alone pickle library.</PackageReleaseNotes>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="System.Memory" Version="4.5.4" />
+    <PackageReference Include="System.Memory" Version="4.5.5" />
   </ItemGroup>
 </Project>

dotnet/Razorvine.Pickle/Pickle/Pickle/Objects/ByteArrayConstructor.cs

@@ -15,9 +15,13 @@ public class ByteArrayConstructor : IObjectConstructor {
 	public object construct(object[] args) {
 		// args for bytearray constructor: [ String string, String encoding ]
 		// args for bytearray constructor (from python3 bytes): [ ArrayList ] or just [byte[]] (when it uses BINBYTES opcode)
-		if (args.Length != 1 && args.Length != 2)
+		// or, zero arguments: empty bytearray.
+		if (args.Length>2)
 			throw new PickleException("invalid pickle data for bytearray; expected 1 or 2 args, got "+args.Length);
 
+		if (args.Length == 0)
+			return new byte[]{};
+		
 		if(args.Length==1) {
 			if(args[0] is byte[]) {
 				return args[0];

dotnet/Razorvine.Pickle/UnitTests/Pickle/UnpicklerTests.cs

@@ -407,6 +407,15 @@ public void TestBytesAndByteArray()
 		Assert.Equal(Encoding.ASCII.GetBytes("ABCDEFGH"), (byte[])U(p3));
 	}
 
+	[Fact]
+	public void TestUnpickleEmptyBytes() {
+		byte[] pickled = {
+			128, 2, 99, 95, 95, 98, 117, 105, 108, 116, 105, 110, 95, 95, 10, 98, 121, 116, 101, 115, 10, 113, 0, 41, 82, 113, 1, 46
+		};
+		byte[] obj = (byte[]) (new Unpickler().loads(pickled));
+		Assert.Empty(obj);
+	}
+
 	[Fact]
 	public void TestArray() 
 	{

dotnet/Razorvine.Pickle/UnitTests/UnitTests.csproj

@@ -7,9 +7,9 @@
     <LangVersion>7.3</LangVersion>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.5.0" />
-    <PackageReference Include="xunit" Version="2.4.1" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
+    <PackageReference Include="xunit" Version="2.4.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>