Fixed null reference issue, inherited IDisposable, and added ExperimentAssignment tracking to EvalFeature

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.3]
+
+- Fixed null reference exception when forcing a rule with a tracking callback set and null tracking data.
+- Experiment assignments are included in EvalFeature as well as Run.
+- IGrowthBook interface fixed to inherit IDisposable.
+
 ## [1.0.2]
 
 - Fixed issue with incorrect logic in GrowthBook.GetFeatureResult<T>() call.

GrowthBook.Tests/CustomTests/RegressionTests.cs

@@ -4,13 +4,74 @@
 using System.Text;
 using System.Threading.Tasks;
 using FluentAssertions;
+using Microsoft.AspNetCore.Mvc;
 using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
 using Xunit;
 
 namespace GrowthBook.Tests.CustomTests;
 
 public class RegressionTests : UnitTest
 {
+    [Fact]
+    public void ExperimentWillResultInAssignmentIfDifferentFromPreviousOrMissing()
+    {
+        const string FeatureName = "test-assignment";
+
+        var feature = new Feature { DefaultValue = false, Rules = new List<FeatureRule> { new() { Coverage = 1d } } };
+
+        var staticFeatures = new Dictionary<string, Feature>
+        {
+            [FeatureName] = feature
+        };
+
+        var context = new Context
+        {
+            Features = staticFeatures
+        };
+
+        var growthBook = new GrowthBook(context);
+
+        var result = growthBook.EvalFeature(FeatureName);
+        var result2 = growthBook.EvalFeature(FeatureName);
+
+        var assignmentsByExperimentKey = growthBook.GetAllResults();
+
+        assignmentsByExperimentKey.Should().NotBeNull("because it must always be a valid collection instance");
+        assignmentsByExperimentKey.Count.Should().Be(1, "because the second experiment was not different");
+    }
+
+    [Fact]
+    public void GetFeatureValueShouldReturnForcedValueEvenWhenTracksIsNull()
+    {
+        const string FeatureName = "test-tracks-default-value";
+        var forcedResult = JToken.FromObject(true);
+
+        var feature = new Feature { DefaultValue = false, Rules = new List<FeatureRule> { new() { Force = forcedResult } } };
+
+        var staticFeatures = new Dictionary<string, Feature>
+        {
+            [FeatureName] = feature
+        };
+
+        var trackingWasCalled = false;
+
+        var context = new Context
+        {
+            Features = staticFeatures,
+            TrackingCallback = (features, tracking) => trackingWasCalled = true
+        };
+
+        var growthBook = new GrowthBook(context);
+
+        var result = growthBook.EvalFeature(FeatureName);
+
+        result.Should().NotBeNull("because a result must be created");
+        result.Value.Should().NotBeNull("because the result value was forced");
+        result.Value.ToString().Should().Be(forcedResult.ToString(), "because that was the forced value");
+        trackingWasCalled.Should().BeFalse("because no tracking data was present");
+    }
+
     [Fact]
     public void GetFeatureValueShouldOnlyReturnFallbackValueWhenTheFeatureResultValueIsNull()
     {

GrowthBook/GrowthBook.cs

@@ -215,7 +215,7 @@ public FeatureResult EvalFeature(string featureId)
                             continue;
                         }
 
-                        if (_trackingCallback != null && rule.Tracks.Any())
+                        if (_trackingCallback != null && rule.Tracks?.Any() == true)
                         {
                             foreach (var trackData in rule.Tracks)
                             {
@@ -251,6 +251,8 @@ public FeatureResult EvalFeature(string featureId)
 
                     var result = RunExperiment(experiment, featureId);
 
+                    TryAssignExperimentResult(experiment, result);
+
                     if (!result.InExperiment || result.Passthrough)
                     {
                         continue;
@@ -281,24 +283,7 @@ public ExperimentResult Run(Experiment experiment)
             {
                 ExperimentResult result = RunExperiment(experiment, null);
 
-                if (!_assigned.TryGetValue(experiment.Key, out ExperimentAssignment prev)
-                    || prev.Result.InExperiment != result.InExperiment
-                    || prev.Result.VariationId != result.VariationId)
-                {
-                    _assigned.Add(experiment.Key, new ExperimentAssignment { Experiment = experiment, Result = result });
-
-                    foreach (Action<Experiment, ExperimentResult> callback in _subscriptions)
-                    {
-                        try
-                        {
-                            callback?.Invoke(experiment, result);
-                        }
-                        catch (Exception ex)
-                        {
-                            _logger.LogError(ex, $"Encountered exception during subscription callback for experiment with key '{experiment.Key}'");
-                        }
-                    }
-                }
+                TryAssignExperimentResult(experiment, result);
 
                 return result;
             }
@@ -327,6 +312,28 @@ public async Task LoadFeatures(GrowthBookRetrievalOptions options = null, Cancel
             }
         }
 
+        private void TryAssignExperimentResult(Experiment experiment, ExperimentResult result)
+        {
+            if (!_assigned.TryGetValue(experiment.Key, out ExperimentAssignment prev)
+                || prev.Result.InExperiment != result.InExperiment
+                || prev.Result.VariationId != result.VariationId)
+            {
+                _assigned.Add(experiment.Key, new ExperimentAssignment { Experiment = experiment, Result = result });
+
+                foreach (Action<Experiment, ExperimentResult> callback in _subscriptions)
+                {
+                    try
+                    {
+                        callback?.Invoke(experiment, result);
+                    }
+                    catch (Exception ex)
+                    {
+                        _logger.LogError(ex, $"Encountered exception during subscription callback for experiment with key '{experiment.Key}'");
+                    }
+                }
+            }
+        }
+
         private ExperimentResult RunExperiment(Experiment experiment, string featureId)
         { 
             // 1. Abort if there aren't enough variations present.

GrowthBook/GrowthBook.csproj

@@ -11,7 +11,7 @@
     <RepositoryUrl>https://github.com/growthbook/growthbook-csharp.git</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
     <PackageTags>GrowthBook,A/B test,feature toggle,flag</PackageTags>
-    <Version>1.0.2</Version>
+    <Version>1.0.3</Version>
     <Title>GrowthBook C# SDK</Title>
     <PackageProjectUrl>https://www.growthbook.io/</PackageProjectUrl>
   </PropertyGroup>

GrowthBook/IGrowthBook.cs

@@ -8,7 +8,7 @@ namespace GrowthBook
     /// <summary>
     /// Providing operations to interact with feature flags.
     /// </summary>
-    public interface IGrowthBook
+    public interface IGrowthBook : IDisposable
     {
         /// <summary>
         /// Checks to see if a feature is on.