Fix deserializing of Emoji types (#2577)

Octokit/Http/AssignableExtensions.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Linq;
+
+namespace Octokit
+{
+    public static class AssignableExtensions
+    {
+        /// <summary>
+        /// Determines whether the <paramref name="genericType"/> is assignable from
+        /// <paramref name="givenType"/> taking into account generic definitions
+        /// </summary>
+        public static bool IsAssignableToGenericType(this Type givenType, Type genericType)
+        {
+            if (givenType == null || genericType == null)
+            {
+                return false;
+            }
+
+            return givenType == genericType
+              || givenType.MapsToGenericTypeDefinition(genericType)
+              || givenType.HasInterfaceThatMapsToGenericTypeDefinition(genericType)
+              || givenType.BaseType.IsAssignableToGenericType(genericType);
+        }
+
+        private static bool HasInterfaceThatMapsToGenericTypeDefinition(this Type givenType, Type genericType)
+        {
+            return givenType
+              .GetInterfaces()
+              .Where(it => it.IsGenericType)
+              .Any(it => it.GetGenericTypeDefinition() == genericType);
+        }
+
+        private static bool MapsToGenericTypeDefinition(this Type givenType, Type genericType)
+        {
+            return genericType.IsGenericTypeDefinition
+              && givenType.IsGenericType
+              && givenType.GetGenericTypeDefinition() == genericType;
+        }
+    }
+}

Octokit/Http/JsonHttpPipeline.cs

@@ -49,7 +49,7 @@ namespace Octokit.Internal
                 // simple json does not support the root node being empty. Will submit a pr but in the mean time....
                 if (!string.IsNullOrEmpty(body) && body != "{}")
                 {
-                    var typeIsDictionary = typeof(IDictionary).IsAssignableFrom(typeof(T));
+                    var typeIsDictionary = typeof(IDictionary).IsAssignableFrom(typeof(T)) || typeof(T).IsAssignableToGenericType(typeof(System.Collections.Generic.IDictionary<,>));
                     var typeIsEnumerable = typeof(IEnumerable).IsAssignableFrom(typeof(T));
                     var responseIsObject = body.StartsWith("{", StringComparison.Ordinal);