Reverse configuration chaininghalter73/reverse-chain

3 files changed, 131 insertions, 32 deletions

diff --git a/src/DefaultBuilder/src/WebApplication.cs b/src/DefaultBuilder/src/WebApplication.cs
index d6c8ca5c60..9d0a837c83 100644
--- a/src/DefaultBuilder/src/WebApplication.cs
+++ b/src/DefaultBuilder/src/WebApplication.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Reflection;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Hosting.Server;
 using Microsoft.AspNetCore.Hosting.Server.Features;
@@ -20,11 +19,11 @@ namespace Microsoft.AspNetCore.Builder
     /// </summary>
     public sealed class WebApplication : IHost, IApplicationBuilder, IEndpointRouteBuilder, IAsyncDisposable
     {
+        internal const string GlobalEndpointRouteBuilderKey = "__GlobalEndpointRouteBuilder";
+
         private readonly IHost _host;
         private readonly List<EndpointDataSource> _dataSources = new();
 
-        internal static string GlobalEndpointRouteBuilderKey = "__GlobalEndpointRouteBuilder";
-
         internal WebApplication(IHost host)
         {
             _host = host;
diff --git a/src/DefaultBuilder/src/WebApplicationBuilder.cs b/src/DefaultBuilder/src/WebApplicationBuilder.cs
index e7e6269d02..dfb153eb9b 100644
--- a/src/DefaultBuilder/src/WebApplicationBuilder.cs
+++ b/src/DefaultBuilder/src/WebApplicationBuilder.cs
@@ -15,11 +15,12 @@ namespace Microsoft.AspNetCore.Builder
     /// </summary>
     public sealed class WebApplicationBuilder
     {
+        private const string EndpointRouteBuilderKey = "__EndpointRouteBuilder";
+
         private readonly HostBuilder _hostBuilder = new();
         private readonly BootstrapHostBuilder _bootstrapHostBuilder;
         private readonly WebApplicationServiceCollection _services = new();
         private readonly List<KeyValuePair<string, string>> _hostConfigurationValues;
-        private const string EndpointRouteBuilderKey = "__EndpointRouteBuilder";
 
         private WebApplication? _builtApplication;
 
@@ -62,7 +63,6 @@ namespace Microsoft.AspNetCore.Builder
             });
 
             // Apply the args to host configuration last since ConfigureWebHostDefaults overrides a host specific setting (the application name).
-
             _bootstrapHostBuilder.ConfigureHostConfiguration(config =>
             {
                 if (args is { Length: > 0 })
@@ -74,7 +74,6 @@ namespace Microsoft.AspNetCore.Builder
                 options.ApplyHostConfiguration(config);
             });
 
-
             Configuration = new();
 
             // Collect the hosted services separately since we want those to run after the user's hosted services
@@ -100,7 +99,7 @@ namespace Microsoft.AspNetCore.Builder
             Host = new ConfigureHostBuilder(hostContext, Configuration, Services);
             WebHost = new ConfigureWebHostBuilder(webHostContext, Configuration, Services);
 
-            Services.AddSingleton<IConfiguration>(Configuration);
+            Services.AddSingleton<IConfiguration>(_ => Configuration);
         }
 
         /// <summary>
@@ -148,14 +147,13 @@ namespace Microsoft.AspNetCore.Builder
                 builder.AddInMemoryCollection(_hostConfigurationValues);
             });
 
+            var chainedConfigSource = new TrackingChainedConfigurationSource(Configuration);
+
             // Wire up the application configuration by copying the already built configuration providers over to final configuration builder.
             // We wrap the existing provider in a configuration source to avoid re-bulding the already added configuration sources.
             _hostBuilder.ConfigureAppConfiguration(builder =>
             {
-                foreach (var provider in ((IConfigurationRoot)Configuration).Providers)
-                {
-                    builder.Sources.Add(new ConfigurationProviderSource(provider));
-                }
+                builder.Add(chainedConfigSource);
 
                 foreach (var (key, value) in ((IConfigurationBuilder)Configuration).Properties)
                 {
@@ -173,17 +171,6 @@ namespace Microsoft.AspNetCore.Builder
                 // we called ConfigureWebHostDefaults on both the _deferredHostBuilder and _hostBuilder.
                 foreach (var s in _services)
                 {
-                    // Skip the configuration manager instance we added earlier
-                    // we're already going to wire it up to this new configuration source
-                    // after we've built the application. There's a chance the user manually added
-                    // this as well but we still need to remove it from the final configuration
-                    // to avoid cycles in the configuration graph
-                    if (s.ServiceType == typeof(IConfiguration) &&
-                        s.ImplementationInstance == Configuration)
-                    {
-                        continue;
-                    }
-
                     services.Add(s);
                 }
 
@@ -205,6 +192,16 @@ namespace Microsoft.AspNetCore.Builder
                 // Drop the reference to the existing collection and set the inner collection
                 // to the new one. This allows code that has references to the service collection to still function.
                 _services.InnerCollection = services;
+
+                // Make builder.Configuration match the final configuration. To do that, we add the additional
+                // providers in the inner _hostBuilders's Configuration to the ConfigurationManager.
+                foreach (var provider in ((IConfigurationRoot)context.Configuration).Providers)
+                {
+                    if (!ReferenceEquals(provider, chainedConfigSource.BuiltProvider))
+                    {
+                        ((IConfigurationBuilder)Configuration).Add(new ConfigurationProviderSource(provider));
+                    }
+                }
             });
 
             // Run the other callbacks on the final host builder
@@ -212,11 +209,6 @@ namespace Microsoft.AspNetCore.Builder
 
             _builtApplication = new WebApplication(_hostBuilder.Build());
 
-            // Make builder.Configuration match the final configuration. To do that
-            // we clear the sources and add the built configuration as a source
-            ((IConfigurationBuilder)Configuration).Sources.Clear();
-            Configuration.AddConfiguration(_builtApplication.Configuration);
-
             // Mark the service collection as read-only to prevent future modifications
             _services.IsReadOnly = true;
 
@@ -301,6 +293,24 @@ namespace Microsoft.AspNetCore.Builder
             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;
diff --git a/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs b/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
index 595f5db980..d6b2326b6a 100644
--- a/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
+++ b/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
@@ -23,7 +23,6 @@ using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
-using Xunit;
 
 [assembly: HostingStartup(typeof(WebApplicationTests.TestHostingStartup))]
 
@@ -706,7 +705,7 @@ namespace Microsoft.AspNetCore.Tests
             var app = builder.Build();
 
             // These are different
-            Assert.NotSame(app.Configuration, builder.Configuration);
+            Assert.Same(app.Configuration, builder.Configuration);
         }
 
         [Fact]
@@ -723,7 +722,28 @@ namespace Microsoft.AspNetCore.Tests
             var app = builder.Build();
 
             // These are different
-            Assert.NotSame(app.Configuration, builder.Configuration);
+            Assert.Same(app.Configuration, builder.Configuration);
+        }
+
+        [Fact]
+        public void AddingMemoryStreamBackedConfigurationWorks()
+        {
+            var builder = WebApplication.CreateBuilder();
+
+            var jsonConfig = @"{ ""foo"": ""bar"" }";
+            using var ms = new MemoryStream();
+            using var sw = new StreamWriter(ms);
+            sw.WriteLine(jsonConfig);
+            sw.Flush();
+
+            ms.Position = 0;
+            builder.Configuration.AddJsonStream(ms);
+
+            Assert.Equal("bar", builder.Configuration["foo"]);
+
+            var app = builder.Build();
+
+            Assert.Equal("bar", app.Configuration["foo"]);
         }
 
         [Fact]
@@ -1496,6 +1516,22 @@ namespace Microsoft.AspNetCore.Tests
         }
 
         [Fact]
+        public void ConfigurationGetDebugViewWorks()
+        {
+            var builder = WebApplication.CreateBuilder();
+
+            builder.Configuration.AddInMemoryCollection(new Dictionary<string, string>
+            {
+                ["foo"] = "bar",
+            });
+
+            var app = builder.Build();
+
+            // Make sure we don't lose "MemoryConfigurationProvider" from GetDebugView() when wrapping the provider.
+            Assert.Contains("foo=bar (MemoryConfigurationProvider)", ((IConfigurationRoot)app.Configuration).GetDebugView());
+        }
+
+        [Fact]
         public void ConfigurationCanBeReloaded()
         {
             var builder = WebApplication.CreateBuilder();
@@ -1524,23 +1560,77 @@ namespace Microsoft.AspNetCore.Tests
             Assert.Equal(1, configSource.ProvidersBuilt);
         }
 
+        [Fact]
+        public void ConfigurationProvidersAreLoadedOnceAfterBuild()
+        {
+            var builder = WebApplication.CreateBuilder();
+
+            var configSource = new RandomConfigurationSource();
+            ((IConfigurationBuilder)builder.Configuration).Sources.Add(configSource);
+
+            using var app = builder.Build();
+
+            Assert.Equal(1, configSource.ProvidersLoaded);
+        }
+
+        [Fact]
+        public void ConfigurationProvidersAreDisposedWithWebApplication()
+        {
+            var builder = WebApplication.CreateBuilder();
+
+            var configSource = new RandomConfigurationSource();
+            ((IConfigurationBuilder)builder.Configuration).Sources.Add(configSource);
+
+            {
+                using var app = builder.Build();
+
+                Assert.Equal(0, configSource.ProvidersDisposed);
+            }
+
+            Assert.Equal(1, configSource.ProvidersDisposed);
+        }
+
+        [Fact]
+        public void ConfigurationProviderTypesArePreserved()
+        {
+            var builder = WebApplication.CreateBuilder();
+
+            ((IConfigurationBuilder)builder.Configuration).Sources.Add(new RandomConfigurationSource());
+
+            var app = builder.Build();
+
+            Assert.Single(((IConfigurationRoot)app.Configuration).Providers.OfType<RandomConfigurationProvider>());
+        }
+
         public class RandomConfigurationSource : IConfigurationSource
         {
             public int ProvidersBuilt { get; set; }
+            public int ProvidersLoaded { get; set; }
+            public int ProvidersDisposed { get; set; }
 
             public IConfigurationProvider Build(IConfigurationBuilder builder)
             {
                 ProvidersBuilt++;
-                return new RandomConfigurationProvider();
+                return new RandomConfigurationProvider(this);
             }
         }
 
-        public class RandomConfigurationProvider : ConfigurationProvider
+        public class RandomConfigurationProvider : ConfigurationProvider, IDisposable
         {
+            private readonly RandomConfigurationSource _source;
+
+            public RandomConfigurationProvider(RandomConfigurationSource source)
+            {
+                _source = source;
+            }
+
             public override void Load()
             {
+                _source.ProvidersLoaded++;
                 Data["Random"] = Guid.NewGuid().ToString();
             }
+
+            public void Dispose() => _source.ProvidersDisposed++;
         }
 
         class ThrowingStartupFilter : IStartupFilter