Make UseUrls() override default hosting confighalter73/38185

2 files changed, 43 insertions, 3 deletions

diff --git a/src/DefaultBuilder/src/WebApplicationBuilder.cs b/src/DefaultBuilder/src/WebApplicationBuilder.cs
index e558cfc3d9..2f55b808a6 100644
--- a/src/DefaultBuilder/src/WebApplicationBuilder.cs
+++ b/src/DefaultBuilder/src/WebApplicationBuilder.cs
@@ -22,6 +22,7 @@ public sealed class WebApplicationBuilder
     private readonly BootstrapHostBuilder _bootstrapHostBuilder;
     private readonly WebApplicationServiceCollection _services = new();
     private readonly List<KeyValuePair<string, string?>> _hostConfigurationValues;
+    private readonly ConfigurationManager _hostConfigurationManager = new();
 
     private WebApplication? _builtApplication;
 
@@ -76,6 +77,8 @@ public sealed class WebApplicationBuilder
         });
 
         Configuration = new();
+        // This is chained as the first configuration source in Configuration so host config can be added later without overriding app config.
+        Configuration.AddConfiguration(_hostConfigurationManager);
 
         // Collect the hosted services separately since we want those to run after the user's hosted services
         _services.TrackHostedServices = true;
@@ -194,6 +197,9 @@ public sealed class WebApplicationBuilder
             // to the new one. This allows code that has references to the service collection to still function.
             _services.InnerCollection = services;
 
+            // Keep any configuration sources added before the TrackingChainedConfigurationSource (namely host configuration from _hostConfigurationValues)
+            // from overriding config values set via Configuration by inserting them at beginning using _hostConfigurationValues.
+            var beforeChainedConfig = true;
             var hostBuilderProviders = ((IConfigurationRoot)context.Configuration).Providers;
 
             if (!hostBuilderProviders.Contains(chainedConfigSource.BuiltProvider))
@@ -201,17 +207,23 @@ public sealed class WebApplicationBuilder
                 // 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();
+                beforeChainedConfig = false;
             }
 
             // Make the ConfigurationManager match the final _hostBuilder's configuration. To do that, we add the additional providers
             // to the inner _hostBuilders's configuration to the ConfigurationManager. We wrap the existing provider in a
-            // configuration source to avoid rebulding or reloading the already added configuration sources.
+            // configuration source to avoid rebuilding or reloading the already added configuration sources.
             foreach (var provider in hostBuilderProviders)
             {
                 // Avoid creating a circular reference to the ConfigurationManager via the chained configuration source.
-                if (!ReferenceEquals(provider, chainedConfigSource.BuiltProvider))
+                if (ReferenceEquals(provider, chainedConfigSource.BuiltProvider))
                 {
-                    ((IConfigurationBuilder)Configuration).Add(new ConfigurationProviderSource(provider));
+                    beforeChainedConfig = false;
+                }
+                else
+                {
+                    IConfigurationBuilder configBuilder = beforeChainedConfig ? _hostConfigurationManager : Configuration;
+                    configBuilder.Add(new ConfigurationProviderSource(provider));
                 }
             }
         });
diff --git a/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs b/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
index 281bd8cc5d..1af6944f4a 100644
--- a/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
+++ b/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
@@ -130,6 +130,34 @@ public class WebApplicationTests
     }
 
     [Fact]
+    public async Task WebApplicationWebHostUseUrls_OverridesDefaultHostingConfiguration()
+    {
+        var builder = new WebApplicationBuilder(new(), bootstrapBuilder =>
+        {
+            bootstrapBuilder.ConfigureHostConfiguration(configBuilder =>
+            {
+                configBuilder.AddInMemoryCollection(new Dictionary<string, string>
+                {
+                    [WebHostDefaults.ServerUrlsKey] = "http://localhost:5000",
+                });
+            });
+        });
+
+        var urls = new List<string>();
+        var server = new MockAddressesServer(urls);
+        builder.Services.AddSingleton<IServer>(server);
+
+        builder.WebHost.UseUrls("http://localhost:5001");
+
+        await using var app = builder.Build();
+
+        await app.StartAsync();
+
+        var url = Assert.Single(urls);
+        Assert.Equal("http://localhost:5001", url);
+    }
+
+    [Fact]
     public async Task WebApplicationUrls_ThrowsInvalidOperationExceptionIfThereIsNoIServerAddressesFeature()
     {
         var builder = WebApplication.CreateBuilder();