wrote failing test cases for deserializing from a ReadOnlyCollection<…

…T> (specifically int, string, double like those for HashSet)

added ReadOnlyCollection<> check to DeSerializeListWithElement.ParseGenericList, since ReadOnlyCollection<> implements IList<>, but throws on .Add :( -- workaround for a poor design decision

src/ServiceStack.Text/Common/DeserializeListWithElements.cs

@@ -12,6 +12,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Reflection;
 
 namespace ServiceStack.Text.Common
@@ -103,7 +104,10 @@ public static IList<T> ParseGenericList(string value, Type createListType, Parse
 		{
 			if ((value = DeserializeListWithElements<TSerializer>.StripList(value)) == null) return null;
 
-			var to = (createListType == null)
+			bool isReadOnly = null == createListType ? false 
+				: createListType.IsGenericType && createListType.GetGenericTypeDefinition() == typeof(ReadOnlyCollection<>);
+
+			var to = (createListType == null || isReadOnly)
 			         	? new List<T>()
 			         	: (IList<T>)ReflectionExtensions.CreateInstance(createListType);
 
@@ -135,7 +139,10 @@ public static IList<T> ParseGenericList(string value, Type createListType, Parse
 
 				}
 			}
-			return to;
+
+			//TODO: 8-10-2011 -- this CreateInstance call should probably be moved over to ReflectionExtensions, 
+			//but not sure how you'd like to go about caching constructors with parameters -- I would probably build a NewExpression, .Compile to a LambdaExpression and cache
+			return isReadOnly ? (IList<T>)Activator.CreateInstance(createListType, to) : to;
 		}
 	}
 

tests/ServiceStack.Text.Tests/BasicStringSerializerTests.cs

@@ -1,12 +1,12 @@
-using System;
-using System.Collections;
-using System.ComponentModel.DataAnnotations;
-using System.Linq;
-using Northwind.Common.ComplexModel;
-using NUnit.Framework;
-using ServiceStack.Common.Extensions;
-using ServiceStack.Common.Tests.Models;
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using Northwind.Common.ComplexModel;
+using NUnit.Framework;
+using ServiceStack.Common.Extensions;
+using ServiceStack.Common.Tests.Models;
 using ServiceStack.Text.Common;
 
 namespace ServiceStack.Text.Tests
@@ -386,6 +386,33 @@ public void Can_convert_string_to_double_HashSet()
 			var toHashSet = Serialize(fromHashSet);
 
 			Assert.That(toHashSet.EquivalentTo(fromHashSet), Is.True);
+		}
+
+		[Test]
+		public void Can_convert_string_to_string_ReadOnlyCollection()
+		{
+			var fromCollection = new ReadOnlyCollection<string>(stringValues);
+			var toCollection = Serialize(fromCollection);
+
+			Assert.That(toCollection.EquivalentTo(fromCollection), Is.True);
+		}
+
+		[Test]
+		public void Can_convert_string_to_int_ReadOnlyCollection()
+		{
+			var fromCollection = new ReadOnlyCollection<int>(intValues);
+			var toCollection = Serialize(fromCollection);
+
+			Assert.That(toCollection.EquivalentTo(fromCollection), Is.True);
+		}
+
+		[Test]
+		public void Can_convert_string_to_double_ReadOnlyCollection()
+		{
+			var fromCollection = new ReadOnlyCollection<double>(doubleValues);
+			var toCollection = Serialize(fromCollection);
+
+			Assert.That(toCollection.EquivalentTo(fromCollection), Is.True);
 		}
 
 		public T Serialize<T>(T model)