UseSpa MissingMethodException

Describe the bug

IApplicationBuilder extension method “UseSpa” fails with MissingMethodException on first web request. Possibly related to the New Use overload changes.

To Reproduce

public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory, IHostEnvironment env) { if (env.EnvironmentName.Equals(“Local”)) { app.UseSpa(spa => { spa.Options.DefaultPage = “/index.html”; spa.UseProxyToSpaDevelopmentServer(“http://localhost:4200/”); }); } }

Exceptions (if any)

System.MissingMethodException HResult=0x80131513 Message=Method not found: 'Microsoft.AspNetCore.Builder.IApplicationBuilder Microsoft.AspNetCore.Builder.UseExtensions.Use(Microsoft.AspNetCore.Builder.IApplicationBuilder, System.Func3<Microsoft.AspNetCore.Http.HttpContext,Microsoft.AspNetCore.Http.RequestDelegate,System.Threading.Tasks.Task>)'. Source=Microsoft.AspNetCore.SpaServices.Extensions StackTrace: at Microsoft.AspNetCore.SpaServices.SpaDefaultPageMiddleware.Attach(ISpaBuilder spaBuilder) at Microsoft.AspNetCore.Builder.SpaApplicationBuilderExtensions.UseSpa(IApplicationBuilder app, Action1 configuration) at Website.Startup.Configure(IApplicationBuilder app, ILoggerFactory loggerFactory, IHostEnvironment env) in C:\Source\Webiste\Startup.cs:line 256 at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder) at Microsoft.AspNetCore.Hosting.ConfigureBuilder.<>c__DisplayClass4_0.<Build>b__0(IApplicationBuilder builder) at Microsoft.AspNetCore.Hosting.ConventionBasedStartup.Configure(IApplicationBuilder app)

Further technical details

Version: .NET 6 preview 4 OS: Windows 10 21H1 Arch: x64

dotnet --info .NET SDK (reflecting any global.json): Version: 6.0.100-preview.3.21202.5 Commit: aee38a6dd4

Runtime Environment: OS Name: Windows OS Version: 10.0.19043 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\6.0.100-preview.3.21202.5\

Host (useful for support): Version: 6.0.0-preview.3.21201.4 Commit: 236cb21e3c

.NET SDKs installed: 3.0.100 [C:\Program Files\dotnet\sdk] 3.1.101 [C:\Program Files\dotnet\sdk] 3.1.115 [C:\Program Files\dotnet\sdk] 5.0.100-rc.2.20479.15 [C:\Program Files\dotnet\sdk] 5.0.200-preview.20601.7 [C:\Program Files\dotnet\sdk] 5.0.300-preview.21258.4 [C:\Program Files\dotnet\sdk] 5.0.300 [C:\Program Files\dotnet\sdk] 6.0.100-preview.3.21202.5 [C:\Program Files\dotnet\sdk]

.NET runtimes installed: Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 5.0.0-rc.2.20475.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 5.0.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 6.0.0-preview.3.21201.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 5.0.0-rc.2.20475.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 5.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 6.0.0-preview.3.21201.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 3.1.15 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 5.0.0-rc.2.20475.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 5.0.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 6.0.0-preview.3.21201.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

[javiercn]

@charbold glad that we were able to figure this out!

[charbold]

It sounds like it compiled against the new method, but than ran on an old version that didn’t have it. You said you were using .NET 6 preview 4, but your dotnet --info says you only have 6.0.100-preview.3.21202.5 installed.

I confirm that you were correct. After I correctly installed the appropriate SDK I was able to run successfully. Apologies.