Adjusts the configuration provider to no longer check top level for feature flags

Author: rossgrambo

src/Microsoft.FeatureManagement/ConfigurationFeatureDefinitionProvider.cs

@@ -201,15 +201,17 @@ private IEnumerable<IConfigurationSection> GetFeatureDefinitionSections()
         {
             const string FeatureManagementSectionName = "FeatureManagement";
 
-            if (_configuration.GetChildren().Any(s => s.Key.Equals(FeatureManagementSectionName, StringComparison.OrdinalIgnoreCase)))
+            //
+            // Look for feature definitions under the "FeatureManagement" section
+            IConfigurationSection featureManagementConfigurationSection = _configuration.GetSection(FeatureManagementSectionName);
+
+            if (featureManagementConfigurationSection.Exists())
             {
-                //
-                // Look for feature definitions under the "FeatureManagement" section
-                return _configuration.GetSection(FeatureManagementSectionName).GetChildren();
+                return featureManagementConfigurationSection.GetChildren();
             }
             else
             {
-                return _configuration.GetChildren();
+                return Enumerable.Empty<IConfigurationSection>();
             }
         }
     }

tests/Tests.FeatureManagement/FeatureManagement.cs

@@ -11,10 +11,13 @@
 using Microsoft.FeatureManagement;
 using Microsoft.FeatureManagement.FeatureFilters;
 using System;
+using System.Collections;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
+using System.Text;
 using System.Threading.Tasks;
 using Xunit;
 
@@ -71,6 +74,30 @@ public async Task ReadsConfiguration()
             Assert.True(called);
         }
 
+        [Fact]
+        public async Task ReadsOnlyFeatureManagmentSection()
+        {
+            MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes("{\"AllowedHosts\": \"*\"}"));
+            IConfiguration config = new ConfigurationBuilder().AddJsonStream(stream).Build();
+
+            var services = new ServiceCollection();
+
+            services
+                .AddSingleton(config)
+                .AddFeatureManagement()
+                .AddFeatureFilter<TestFilter>();
+
+            ServiceProvider serviceProvider = services.BuildServiceProvider();
+
+            IFeatureManager featureManager = serviceProvider.GetRequiredService<IFeatureManager>();
+
+            await foreach (string featureName in featureManager.GetFeatureNamesAsync())
+            {
+                // Fail, as no features should be found
+                Assert.True(false);
+            }
+        }
+
         [Fact]
         public async Task Integrates()
         {

tests/Tests.FeatureManagement/Tests.FeatureManagement.csproj

@@ -16,7 +16,7 @@
   <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp2.1'">
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
     <PackageReference Include="Microsoft.AspNetCore" Version="2.1.7" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="2.1.1" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="3.1.32" />
     <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="2.1.1" />
     <PackageReference Include="Microsoft.AspNetCore.Mvc" Version="2.1.3" />
   </ItemGroup>