fix: Ensure AddPolicyName without adding a Provider does not get stuck in infinite loop (#606)

* Fix issue when adding a DefaultNamePolicy

* If you add a AddPolicyName without having previously added a Provider,
  the code will get stuck trying to resolve IFeatureClient

Signed-off-by: Kyle Julian <[email protected]>

* Address copilot comments and improve unit test coverage

Signed-off-by: Kyle Julian <[email protected]>

---------

Signed-off-by: Kyle Julian <[email protected]>

Author: kylejuliandev

src/OpenFeature.Hosting/OpenFeatureBuilderExtensions.cs

@@ -223,16 +223,25 @@ internal static OpenFeatureBuilder AddPolicyBasedClient(this OpenFeatureBuilder
         {
             var policy = provider.GetRequiredService<IOptions<PolicyNameOptions>>().Value;
             var name = policy.DefaultNameSelector(provider);
-            if (name == null)
-            {
-                return provider.GetRequiredService<IFeatureClient>();
-            }
-            return provider.GetRequiredKeyedService<IFeatureClient>(name);
+            return ResolveFeatureClient(provider, name);
         });
 
         return builder;
     }
 
+    private static IFeatureClient ResolveFeatureClient(IServiceProvider provider, string? name = null)
+    {
+        var api = provider.GetRequiredService<Api>();
+        var client = api.GetClient(name);
+        var context = provider.GetService<EvaluationContext>();
+        if (context != null)
+        {
+            client.SetContext(context);
+        }
+
+        return client;
+    }
+
     /// <summary>
     /// Configures policy name options for OpenFeature using the specified options type.
     /// </summary>

test/OpenFeature.Hosting.Tests/OpenFeatureBuilderExtensionsTests.cs

@@ -539,7 +539,7 @@ public void AddPolicyBasedClient_AddsScopedFeatureClient()
         Assert.NotNull(client);
     }
 
-    [Fact(Skip = "Bug due to https://github.com/open-feature/dotnet-sdk/issues/543")]
+    [Fact]
     public void AddPolicyBasedClient_WithNoDefaultName_AddsScopedFeatureClient()
     {
         // Arrange
@@ -559,4 +559,34 @@ public void AddPolicyBasedClient_WithNoDefaultName_AddsScopedFeatureClient()
         var client = scope.ServiceProvider.GetService<IFeatureClient>();
         Assert.NotNull(client);
     }
+
+    [Fact]
+    public void AddPolicyBasedClient_WithEvaluationContext()
+    {
+        // Arrange
+        _services.AddSingleton(sp => Api.Instance);
+
+        var context = EvaluationContext.Builder()
+            .Set("userId", "user-123")
+            .Build();
+
+        _services.AddTransient(_ => context);
+
+        _services.AddOptions<PolicyNameOptions>()
+            .Configure(options => options.DefaultNameSelector = _ => "default-name");
+
+        _systemUnderTest.AddProvider("default-name", (_, key) => new NoOpFeatureProvider());
+
+        // Act
+        _systemUnderTest.AddPolicyBasedClient();
+
+        // Assert
+        using var serviceProvider = _services.BuildServiceProvider();
+        using var scope = serviceProvider.CreateScope();
+        var client = scope.ServiceProvider.GetService<IFeatureClient>();
+        Assert.NotNull(client);
+
+        var actualContext = client.GetContext();
+        Assert.Equal(context, actualContext);
+    }
 }