Minor fixes and cleanup

Author: jhonabreul

Common/Api/OptimizationBacktestJsonConverter.cs

@@ -30,7 +30,6 @@ namespace QuantConnect.Api
     /// </summary>
     public class OptimizationBacktestJsonConverter : JsonConverter
     {
-
         private static Dictionary<string, int> StatisticsIndices = new()
         {
             { PerformanceMetrics.Alpha, 0 },
@@ -60,19 +59,10 @@ public class OptimizationBacktestJsonConverter : JsonConverter
             { PerformanceMetrics.DrawdownRecovery, 24 },
         };
 
-        private static string[] _statisticNames;
-
-        private static string[] StatisticNames
-        {
-            get
-            {
-                _statisticNames ??= StatisticsIndices
-                    .OrderBy(kvp => kvp.Value)
-                    .Select(kvp => kvp.Key)
-                    .ToArray();
-                return _statisticNames;
-            }
-        }
+        private static string[] StatisticNames { get; } = StatisticsIndices
+            .OrderBy(kvp => kvp.Value)
+            .Select(kvp => kvp.Key)
+            .ToArray();
 
         // Only 21 Lean statistics where supported when the serialized statistics where a json array
         private static int ArrayStatisticsCount = 21;
@@ -211,9 +201,11 @@ public override object ReadJson(JsonReader reader, Type objectType, object exist
             {
                 if (jStatistics.Type == JTokenType.Array)
                 {
+                    var statsCount = Math.Min(ArrayStatisticsCount, (jStatistics as JArray).Count);
                     statistics = new Dictionary<string, string>(StatisticsIndices
-                        .Take(ArrayStatisticsCount)
-                        .Select(kvp => KeyValuePair.Create(kvp.Key, jStatistics[kvp.Value].Value<string>())));
+                        .Where(kvp => kvp.Value < statsCount)
+                        .Select(kvp => KeyValuePair.Create(kvp.Key, jStatistics[kvp.Value].Value<string>()))
+                        .Where(kvp => kvp.Value != null));
                 }
                 else
                 {

Tests/Api/OptimizationBacktestJsonConverterTests.cs

@@ -52,6 +52,9 @@ public class OptimizationBacktestJsonConverterTests
         private const string _validOldStatsDeserialization3 = "{\"name\":\"ImABacktestName\",\"id\":\"backtestId\",\"progress\":0.0,\"exitCode\":0," +
             "\"statistics\":[0.374,0.217,0.047,-4.51,2.86,-0.664,52.602,17.800,6300000.00,0.196,1.571,27.0,123.888,77.188,0.63,1.707,1390.49,180.0,0.233,-0.558,73.0]," +
             "\"parameterSet\":{\"pinocho\":\"19\",\"pepe\":\"-1\"},\"equity\":[[1,1.0],[2,2.0],[3,3.0]]}";
+        private const string _validOldStatsDeserializationWithLessStats = "{\"name\":\"ImABacktestName\",\"id\":\"backtestId\",\"progress\":0.0,\"exitCode\":0," +
+            "\"statistics\":[0.374,0.217,0.047,-4.51,2.86,-0.664,52.602,17.800,6300000.00,0.196,1.571,27.0,123.888,77.188,0.63]," +
+            "\"parameterSet\":{\"pinocho\":\"19\",\"pepe\":\"-1\"},\"equity\":[[1,1.0],[2,2.0],[3,3.0]]}";
 
         [Test]
         public void SerializationNulls()
@@ -187,6 +190,7 @@ public void SerializationWithCustomStatistics()
         [TestCase(_validOldStatsDeserialization, false, 21)]
         [TestCase(_validOldStatsDeserialization2, false, 21)]
         [TestCase(_validOldStatsDeserialization3, false, 21)]
+        [TestCase(_validOldStatsDeserializationWithLessStats, false, 15)]
         [TestCase(_validSerializationWithCustomStats, true, 25)]
         public void Deserialization(string serialization, bool hasCustomStats, int expectedLeanStats)
         {