Handle tests adding non-reloadable config sources

Author: halter73

src/DefaultBuilder/src/ConfigurationProviderSource.cs

@@ -0,0 +1,83 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Primitives;
+
+namespace Microsoft.AspNetCore.Builder
+{
+    internal sealed class ConfigurationProviderSource : IConfigurationSource
+    {
+        private readonly IConfigurationProvider _configurationProvider;
+
+        public ConfigurationProviderSource(IConfigurationProvider configurationProvider)
+        {
+            _configurationProvider = configurationProvider;
+        }
+
+        public IConfigurationProvider Build(IConfigurationBuilder builder)
+        {
+            return new IgnoreFirstLoadConfigurationProvider(_configurationProvider);
+        }
+
+        // These providers have already been loaded, so no need to reload initially.
+        // Otherwise, providers that cannot be reloaded like StreamConfigurationProviders will fail.
+        private sealed class IgnoreFirstLoadConfigurationProvider : IConfigurationProvider
+        {
+            private readonly IConfigurationProvider _provider;
+
+            private bool _hasIgnoredFirstLoad;
+
+            public IgnoreFirstLoadConfigurationProvider(IConfigurationProvider provider)
+            {
+                _provider = provider;
+            }
+
+            public IEnumerable<string> GetChildKeys(IEnumerable<string> earlierKeys, string parentPath)
+            {
+                return _provider.GetChildKeys(earlierKeys, parentPath);
+            }
+
+            public IChangeToken GetReloadToken()
+            {
+                return _provider.GetReloadToken();
+            }
+
+            public void Load()
+            {
+                if (!_hasIgnoredFirstLoad)
+                {
+                    _hasIgnoredFirstLoad = true;
+                    return;
+                }
+
+                _provider.Load();
+            }
+
+            public void Set(string key, string value)
+            {
+                _provider.Set(key, value);
+            }
+
+            public bool TryGet(string key, out string value)
+            {
+                return _provider.TryGet(key, out value);
+            }
+
+            public override bool Equals(object? obj)
+            {
+                return _provider.Equals(obj);
+            }
+
+            public override int GetHashCode()
+            {
+                return _provider.GetHashCode();
+            }
+
+            public override string? ToString()
+            {
+                return _provider.ToString();
+            }
+        }
+    }
+}

src/DefaultBuilder/src/TrackingChainedConfigurationSource.cs

@@ -0,0 +1,25 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.Extensions.Configuration;
+
+namespace Microsoft.AspNetCore.Builder
+{
+    internal sealed class TrackingChainedConfigurationSource : IConfigurationSource
+    {
+        private readonly ChainedConfigurationSource _chainedConfigurationSource = new();
+
+        public TrackingChainedConfigurationSource(ConfigurationManager configManager)
+        {
+            _chainedConfigurationSource.Configuration = configManager;
+        }
+
+        public IConfigurationProvider? BuiltProvider { get; set; }
+
+        public IConfigurationProvider Build(IConfigurationBuilder builder)
+        {
+            BuiltProvider = _chainedConfigurationSource.Build(builder);
+            return BuiltProvider;
+        }
+    }
+}

src/DefaultBuilder/src/WebApplicationBuilder.cs

@@ -198,9 +198,8 @@ public WebApplication Build()
 
                 if (!hostBuilderProviders.Contains(chainedConfigSource.BuiltProvider))
                 {
-                    // Something removed the TrackingChainedConfigurationSource pointing back to the ConfigurationManager.
-                    // This is likely a test using WebApplicationFactory<TEntryPoint>.
-                    // We replicate the effect by clearing the ConfingurationManager sources.
+                    // Something removed the _hostBuilder's TrackingChainedConfigurationSource pointing back to the ConfigurationManager.
+                    // This is likely a test using WebApplicationFactory. Replicate the effect by clearing the ConfingurationManager sources.
                     ((IConfigurationBuilder)Configuration).Sources.Clear();
                 }
 
@@ -303,38 +302,5 @@ public LoggingBuilder(IServiceCollection services)
 
             public IServiceCollection Services { get; }
         }
-
-        private sealed class TrackingChainedConfigurationSource : IConfigurationSource
-        {
-            private readonly ChainedConfigurationSource _chainedConfigurationSource = new();
-
-            public TrackingChainedConfigurationSource(ConfigurationManager configManager)
-            {
-                _chainedConfigurationSource.Configuration = configManager;
-            }
-
-            public IConfigurationProvider? BuiltProvider { get; set; }
-
-            public IConfigurationProvider Build(IConfigurationBuilder builder)
-            {
-                BuiltProvider = _chainedConfigurationSource.Build(builder);
-                return BuiltProvider;
-            }
-        }
-
-        private sealed class ConfigurationProviderSource : IConfigurationSource
-        {
-            private readonly IConfigurationProvider _configurationProvider;
-
-            public ConfigurationProviderSource(IConfigurationProvider configurationProvider)
-            {
-                _configurationProvider = configurationProvider;
-            }
-
-            public IConfigurationProvider Build(IConfigurationBuilder builder)
-            {
-                return _configurationProvider;
-            }
-        }
     }
 }