-Refactored property default value creation

Src/Newtonsoft.Json.Tests/Serialization/ContractResolverTests.cs

@@ -108,6 +108,35 @@ namespace Newtonsoft.Json.Tests.Serialization
     [TestFixture]
     public class ContractResolverTests : TestFixtureBase
     {
+        [Test]
+        public void JsonPropertyDefaultValue()
+        {
+            JsonProperty p = new JsonProperty();
+
+            Assert.AreEqual(null, p.GetResolvedDefaultValue());
+            Assert.AreEqual(null, p.DefaultValue);
+
+            p.PropertyType = typeof(int);
+
+            Assert.AreEqual(0 , p.GetResolvedDefaultValue());
+            Assert.AreEqual(null, p.DefaultValue);
+
+            p.PropertyType = typeof(DateTime);
+
+            Assert.AreEqual(new DateTime(), p.GetResolvedDefaultValue());
+            Assert.AreEqual(null, p.DefaultValue);
+
+            p.PropertyType = null;
+
+            Assert.AreEqual(null, p.GetResolvedDefaultValue());
+            Assert.AreEqual(null, p.DefaultValue);
+
+            p.PropertyType = typeof(CompareOptions);
+
+            Assert.AreEqual(CompareOptions.None, (CompareOptions)p.GetResolvedDefaultValue());
+            Assert.AreEqual(null, p.DefaultValue);
+        }
+
         [Test]
         public void ListInterface()
         {

Src/Newtonsoft.Json/Serialization/JsonProperty.cs

@@ -41,8 +41,10 @@ namespace Newtonsoft.Json.Serialization
         internal bool _hasExplicitDefaultValue;
         internal object _defaultValue;
 
+        private bool _hasGeneratedDefaultValue;
         private string _propertyName;
         private bool _skipPropertyNameEscape;
+        private Type _propertyType;
 
         // use to cache contract during deserialization
         internal JsonContract PropertyContract { get; set; }
@@ -109,7 +111,18 @@ namespace Newtonsoft.Json.Serialization
         /// Gets or sets the type of the property.
         /// </summary>
         /// <value>The type of the property.</value>
-        public Type PropertyType { get; set; }
+        public Type PropertyType
+        {
+            get { return _propertyType; }
+            set
+            {
+                if (_propertyType != value)
+                {
+                    _propertyType = value;
+                    _hasGeneratedDefaultValue = false;
+                }
+            }
+        }
 
         /// <summary>
         /// Gets or sets the <see cref="JsonConverter" /> for the property.
@@ -154,7 +167,13 @@ namespace Newtonsoft.Json.Serialization
         /// <value>The default value.</value>
         public object DefaultValue
         {
-            get { return _defaultValue; }
+            get
+            {
+                if (!_hasExplicitDefaultValue)
+                    return null;
+
+                return _defaultValue;
+            }
             set
             {
                 _hasExplicitDefaultValue = true;
@@ -164,8 +183,14 @@ namespace Newtonsoft.Json.Serialization
 
         internal object GetResolvedDefaultValue()
         {
-            if (!_hasExplicitDefaultValue && PropertyType != null)
-                return ReflectionUtils.GetDefaultValue(PropertyType);
+            if (_propertyType == null)
+                return null;
+
+            if (!_hasExplicitDefaultValue && !_hasGeneratedDefaultValue)
+            {
+                _defaultValue = ReflectionUtils.GetDefaultValue(PropertyType);
+                _hasGeneratedDefaultValue = true;
+            }
 
             return _defaultValue;
         }