Empty list serialization

global.json

@@ -1,7 +1,4 @@
 {
-  "sdk": {
-    "version": "2.1.500"
-  },
   "msbuild-sdks": {
     "MSBuild.Sdk.Extras": "1.5.4",
     "__MSBuild.Sdk.Extras": "1.6.20-preview"

src/protobuf-net.Test/Meta/Lists.cs

@@ -124,6 +124,53 @@ public void RoundTripTypedList_String()
             Assert.True(obj.ListString.SequenceEqual(clone.ListString));
         }
 
+        [Fact]
+        public void RoundTripTypedList_String_Null()
+        {
+            var model = TypeModel.Create();
+            model.Add(typeof(TypeWithLists), false).Add(1, "ListString");
+            TypeWithLists obj = new TypeWithLists();
+            obj.ListString = null;
+
+            TypeWithLists clone = (TypeWithLists)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.ListString);
+
+            model.CompileInPlace();
+            clone = (TypeWithLists)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.ListString);
+
+            clone = (TypeWithLists)model.Compile().DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.ListString);
+        }
+
+        [Fact]
+        public void RoundTripTypedList_String_Empty()
+        {
+            var model = TypeModel.Create();
+            model.Add(typeof(TypeWithLists), false).Add(1, "ListString");
+            TypeWithLists obj = new TypeWithLists();
+            obj.ListString = new List<string>();
+
+            TypeWithLists clone = (TypeWithLists)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.ListString);
+            Assert.Empty(clone.ListString);
+
+            model.CompileInPlace();
+            clone = (TypeWithLists)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.ListString);
+            Assert.Empty(clone.ListString);
+
+            clone = (TypeWithLists)model.Compile().DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.ListString);
+            Assert.Empty(clone.ListString);
+        }
+
         [Fact]
         public void RoundTripTypedIList_String()
         {
@@ -151,6 +198,53 @@ public void RoundTripTypedIList_String()
             Assert.True(obj.IListStringTyped.SequenceEqual(clone.IListStringTyped));
         }
 
+        [Fact]
+        public void RoundTripTypedIList_String_Null()
+        {
+            var model = TypeModel.Create();
+            model.Add(typeof(TypeWithLists), false).Add(2, "IListStringTyped");
+            TypeWithLists obj = new TypeWithLists();
+            obj.IListStringTyped = null;
+
+            TypeWithLists clone = (TypeWithLists)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.IListStringTyped);
+
+            model.CompileInPlace();
+            clone = (TypeWithLists)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.IListStringTyped);
+
+            clone = (TypeWithLists)model.Compile().DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.IListStringTyped);
+        }
+
+        [Fact]
+        public void RoundTripTypedIList_String_Empty()
+        {
+            var model = TypeModel.Create();
+            model.Add(typeof(TypeWithLists), false).Add(2, "IListStringTyped");
+            TypeWithLists obj = new TypeWithLists();
+            obj.IListStringTyped = new List<string>();
+
+            TypeWithLists clone = (TypeWithLists)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.IListStringTyped);
+            Assert.True(obj.IListStringTyped.Count == 0);
+
+            model.CompileInPlace();
+            clone = (TypeWithLists)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.IListStringTyped);
+            Assert.True(obj.IListStringTyped.Count == 0);
+
+            clone = (TypeWithLists)model.Compile().DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.IListStringTyped);
+            Assert.True(obj.IListStringTyped.Count == 0);
+        }
+
 
         [Fact]
         public void RoundTripArrayList_String()
@@ -315,6 +409,84 @@ public void RoundTripIList_Int32()
             Assert.True(obj.IListInt32Untyped.Cast<int>().SequenceEqual(clone.IListInt32Untyped.Cast<int>()));
         }
 
+        [Fact]
+        public void RoundTripArray_String()
+        {
+            var model = TypeModel.Create();
+            model.Add(typeof(Arrays), false).Add(4, "BasicArray");
+            Arrays obj = new Arrays();
+            obj.BasicArray = new[] { "abc", "def" };
+
+            Arrays clone = (Arrays)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.BasicArray);
+            Assert.True(obj.BasicArray.SequenceEqual(clone.BasicArray));
+
+            model.CompileInPlace();
+            clone = (Arrays)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.BasicArray);
+            Assert.True(obj.BasicArray.SequenceEqual(clone.BasicArray));
+
+            clone = (Arrays)model.Compile().DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.BasicArray);
+            Assert.True(obj.BasicArray.SequenceEqual(clone.BasicArray));
+        }
+
+
+        [Fact]
+        public void RoundTripArray_String_Null()
+        {
+            var model = TypeModel.Create();
+            model.Add(typeof(Arrays), false).Add(4, "BasicArray");
+            Arrays obj = new Arrays();
+            obj.BasicArray = null;
+
+            Arrays clone = (Arrays)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.BasicArray);
+
+            model.CompileInPlace();
+            clone = (Arrays)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.BasicArray);
+
+            clone = (Arrays)model.Compile().DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.Null(clone.BasicArray);
+        }
+
+        [Fact]
+        public void RoundTripArray_String_Empty()
+        {
+            var model = TypeModel.Create();
+            model.Add(typeof(Arrays), false).Add(4, "BasicArray");
+            Arrays obj = new Arrays();
+            obj.BasicArray = new string[0];
+
+            Arrays clone = (Arrays)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.BasicArray);
+            Assert.True(obj.BasicArray.Length == 0);
+
+            model.CompileInPlace();
+            clone = (Arrays)model.DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.BasicArray);
+            Assert.True(obj.BasicArray.Length == 0);
+
+            clone = (Arrays)model.Compile().DeepClone(obj);
+            Assert.NotNull(clone);
+            Assert.NotNull(clone.BasicArray);
+            Assert.True(obj.BasicArray.Length == 0);
+        }
+
+        public class Arrays
+        {
+            public string[] BasicArray { get; set; }
+        }
+
         public class NastyType
         {