Move RuntimePropertyCache to JsonClassInfo

Author: svick

src/System.Text.Json/src/System/Text/Json/Serialization/JsonClassInfo.AddProperty.cs

@@ -212,24 +212,25 @@ internal JsonPropertyInfo CreateRootObject(JsonSerializerOptions options)
 
         internal JsonPropertyInfo GetOrAddPolymorphicProperty(JsonPropertyInfo property, Type runtimePropertyType, JsonSerializerOptions options)
         {
-            static JsonPropertyInfo CreateRuntimeProperty(Type runtimePropertyType, (JsonPropertyInfo property, JsonSerializerOptions options, Type classType) arg)
+            static JsonPropertyInfo CreateRuntimeProperty((JsonPropertyInfo property, Type runtimePropertyType) key, (JsonSerializerOptions options, Type classType) arg)
             {
                 JsonPropertyInfo runtimeProperty = CreateProperty(
-                    arg.property.DeclaredPropertyType, runtimePropertyType,
-                    arg.property.ImplementedPropertyType,
-                    arg.property.PropertyInfo,
+                    key.property.DeclaredPropertyType, key.runtimePropertyType,
+                    key.property.ImplementedPropertyType,
+                    key.property.PropertyInfo,
                     parentClassType: arg.classType,
                     converter: null,
                     options: arg.options);
 
-                arg.property.CopyRuntimeSettingsTo(runtimeProperty);
+                key.property.CopyRuntimeSettingsTo(runtimeProperty);
 
                 return runtimeProperty;
             }
 
-            var cache = LazyInitializer.EnsureInitialized(ref property.RuntimePropertyCache, () => new ConcurrentDictionary<Type, JsonPropertyInfo>());
+            ConcurrentDictionary<(JsonPropertyInfo, Type), JsonPropertyInfo> cache =
+                LazyInitializer.EnsureInitialized(ref RuntimePropertyCache, () => new ConcurrentDictionary<(JsonPropertyInfo, Type), JsonPropertyInfo>());
 
-            return cache.GetOrAdd(runtimePropertyType, (type, arg) => CreateRuntimeProperty(type, arg), (property, options, Type));
+            return cache.GetOrAdd((property, runtimePropertyType), (key, arg) => CreateRuntimeProperty(key, arg), (options, Type));
         }
     }
 }

src/System.Text.Json/src/System/Text/Json/Serialization/JsonClassInfo.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Collections;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
@@ -27,6 +28,9 @@ internal sealed partial class JsonClassInfo
         // All of the serializable properties on a POCO (except the optional extension property) keyed on property name.
         public volatile Dictionary<string, JsonPropertyInfo> PropertyCache;
 
+        // Serializable runtime/polymorphic proerties, keyed on property and runtime type.
+        public ConcurrentDictionary<(JsonPropertyInfo, Type), JsonPropertyInfo> RuntimePropertyCache;
+
         // All of the serializable properties on a POCO including the optional extension property.
         // Used for performance during serialization instead of 'PropertyCache' above.
         public volatile JsonPropertyInfo[] PropertyCacheArray;

src/System.Text.Json/src/System/Text/Json/Serialization/JsonPropertyInfo.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Collections;
-using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Reflection;
 using System.Text.Json.Serialization;
@@ -585,7 +584,5 @@ private void VerifyWrite(int originalDepth, Utf8JsonWriter writer)
                 ThrowHelper.ThrowJsonException_SerializationConverterWrite(ConverterBase);
             }
         }
-
-        public ConcurrentDictionary<Type, JsonPropertyInfo> RuntimePropertyCache;
     }
 }