After upgrading to .NET Standard 2.1 and Blazor v3.1.0-preview4.19579.2, Blazor WebAssembly projects no longer work. #17619

Rauce · 2019-12-05T17:06:54Z

To rule out any project-specific issues, I followed the instructions at https://docs.microsoft.com/en-us/aspnet/core/blazor/get-started?view=aspnetcore-3.1&tabs=visual-studio to create a new clean Blazor WebAssembly project.

I can confirm the new project is created targeting .NET Standard 2.1, with Nuget Blazor package versions v3.1.0-preview4.19579.2.

After the project is created, without modifying any of the project files, I simply hit 'Start Debugging' in Visual Studio (2019 v16.4).

In the first build attempt I get the following single error:

Code: <blank>
Description: ILLink failed with exited code 1
Project: BlazorApp1
File: Blazor.MonoRuntime.targets
Line: 201

If I then immediately immediately try 'Start Debugging' again, it builds without this error, but in the launched browser window the following error appears instead:

An error occurred while starting the application.
System.IO.DirectoryNotFoundException: C:\Users\<My Name>\source\repos\BlazorApp1\BlazorApp1\bin\Debug\netstandard2.1\dist\
   at Microsoft.Extensions.FileProviders.PhysicalFileProvider..ctor(String root, ExclusionFilters filters)
   at Microsoft.Extensions.FileProviders.PhysicalFileProvider..ctor(String root)
   at Microsoft.AspNetCore.Builder.BlazorHostingApplicationBuilderExtensions.UseClientSideBlazorFiles(IApplicationBuilder app, String clientAssemblyFilePath)
   at Microsoft.AspNetCore.Blazor.DevServer.Server.Startup.Configure(IApplicationBuilder app, IWebHostEnvironment environment, IConfiguration configuration)
   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.GenericWebHostBuilder.<>c__DisplayClass13_0.<UseStartup>b__2(IApplicationBuilder app)
   at Microsoft.AspNetCore.Server.IISIntegration.IISSetupFilter.<>c__DisplayClass4_0.<Configure>b__0(IApplicationBuilder app)
   at Microsoft.AspNetCore.HostFilteringStartupFilter.<>c__DisplayClass0_0.<Configure>b__0(IApplicationBuilder app)
   at Microsoft.AspNetCore.Hosting.GenericWebHostService.StartAsync(CancellationToken cancellationToken)

If I revert this project back to .NET Standard 2.0 and Blazor v3.1.0-preview3.19555.2, it builds and runs without any issues.

Here's the output of dotnet --info

.NET Core SDK (reflecting any global.json):
 Version:   3.1.100
 Commit:    cd82f021f4

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.17763
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.1.100\

Host (useful for support):
  Version: 3.1.0
  Commit:  65f04fb6db

.NET Core SDKs installed:
  2.1.602 [C:\Program Files\dotnet\sdk]
  2.1.801 [C:\Program Files\dotnet\sdk]
  2.1.802 [C:\Program Files\dotnet\sdk]
  2.2.202 [C:\Program Files\dotnet\sdk]
  2.2.401 [C:\Program Files\dotnet\sdk]
  2.2.402 [C:\Program Files\dotnet\sdk]
  3.0.100-preview8-013656 [C:\Program Files\dotnet\sdk]
  3.0.100-rc1-014190 [C:\Program Files\dotnet\sdk]
  3.0.100 [C:\Program Files\dotnet\sdk]
  3.1.100 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.6 [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 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.6 [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 3.0.0-preview8.19405.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-rc1.19457.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.6 [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 3.0.0-preview8-28405-07 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-rc1-19456-20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.0.0-preview8-28405-07 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.0.0-rc1-19456-20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Any ideas?

The text was updated successfully, but these errors were encountered:

simonpbond · 2019-12-05T17:09:58Z

@javiercn
Also having the same issue, upgrading a 3.0 to 3.1 Blazor WebAssembly (Preview 4).

5>Could not execute because the specified command or file was not found. 5>Possible reasons for this include: 5> * You misspelled a built-in dotnet command. 5> * You intended to execute a .NET Core program, but dotnet-C:\Users\Simon does not exist. 5> * You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH. 5>C:\Users\Simon Bond\.nuget\packages\microsoft.aspnetcore.blazor.build\3.1.0-preview4.19579.2\targets\Blazor.MonoRuntime.targets(204,5): error : ILLink failed with exited code 1.

javiercn · 2019-12-05T17:10:00Z

@Rauce thanks for contacting us.

I'm not sure what can be going on. I would suggest you first try to update to the latest released blazor version, which is preview4 and is built on top of the .NET Core 3.1.0 RTM

Rauce · 2019-12-05T17:14:04Z

@javiercn

I can confirm the new project I tested with is created targeting .NET Standard 2.1, with Nuget Blazor package versions v3.1.0-preview4.19579.2.

.NET Core 3.1.0 RTM is installed.

javiercn · 2019-12-05T17:15:38Z

@pranavkm Based on this, this seems to be missing the application name, is that correct?
C:\Users\<My Name>\source\repos\BlazorApp1\BlazorApp1\bin\Debug\netstandard2.1\dist\

Rauce · 2019-12-05T17:27:21Z

FYI.

If I revert my projects back to .NET Standard 2.0 and Blazor v3.1.0-preview3.19555.2 (while keeping VS2019 16.4.0 and .NET Core 3.1.0 RTM), they build and run without any issues. (I added this to original issue description).

simonpbond · 2019-12-05T17:29:28Z

I think you can reproduce this by creating a new Blazor WebAssembly (ASP.NET Core Hosted) project (VS16.4, Latest Templates), via the VS UI, and try to rebuild the default generated Client project.

GerritBergen · 2019-12-06T15:20:50Z

Having issues too. Anyone got a workaround?

GerritBergen · 2019-12-06T15:28:36Z

Disabling linking on build seems to let me build right now.

  <PropertyGroup>
    <BlazorLinkOnBuild>false</BlazorLinkOnBuild>
  </PropertyGroup>

pranavkm · 2019-12-09T21:07:56Z

Could one of you share a minimal project that reproduces the build error? I tried @simonpbond's suggestion

I think you can reproduce this by creating a new Blazor WebAssembly (ASP.NET Core Hosted) project (VS16.4, Latest Templates), via the VS UI, and try to rebuild the default generated Client project.

and haven't been able to reproduce the error.

simonpbond · 2019-12-09T21:16:28Z

@pranavkm Reproduced project
I try to rebuild the .Client project, it actually built on first try, then on second and third try it failed with IL Link error. This is just the default VS generated project as mentioned above.

ILLink failed with exited code 1.

pranavkm · 2019-12-09T21:28:39Z

Thanks!

pranavkm · 2019-12-10T17:27:18Z

Still no luck. I tried running rebuild a couple of times on the BlazorRequestedRepo.Client project, tried rebuilding with changes to file and regular builds. All of these succeeded. Is there a specific sequence you're running? Here are a couple of things that would help

Could you grab the build logs from VS when this happens? To do this, you'll need to install this extension: https://marketplace.visualstudio.com/items?itemName=VisualStudioProductTeam.ProjectSystemTools. Once installed go to View > Other Windows > Build Logging and click on the ▶️ button (Start build logging). Attach the one from the failing build to this issue.
Can you look at the Output window and see if it includes any additional content as to why the task failed?

jspuij · 2019-12-11T10:41:02Z

Possibly the same one as this one:
#17754

simonpbond · 2019-12-11T10:46:50Z

Possibly the same one as this one:
#17754

@jspuij @pranavkm Can confirm this has solved the issue for me, thank you.

Rauce · 2019-12-11T11:08:32Z

Woohoo!

@jspuij's solution in #17754 (#17754 (comment)) fixed this error - my project is working again.

pranavkm · 2019-12-11T19:04:14Z

We'll use the other to track fixing this for the next release.

mkArtakMSFT added area-blazor Includes: Blazor, Razor Components feature-blazor-wasm This issue is related to and / or impacts Blazor WebAssembly labels Dec 5, 2019

Rauce changed the title ~~After upgrading to VS2019 16.4 and .NET Core 3.1, Blazor WebAssembly projects no longer work.~~ After upgrading to .NET Standard 2.1 and Blazor v3.1.0-preview4.19579.2, Blazor WebAssembly projects no longer work. Dec 5, 2019

mkArtakMSFT added the investigate label Dec 5, 2019

mkArtakMSFT assigned pranavkm Dec 5, 2019

mkArtakMSFT added this to the blazor-wasm-preview5 milestone Dec 5, 2019

pranavkm added the Needs: Author Feedback The author of this issue needs to respond in order for us to continue investigating this issue. label Dec 10, 2019

ghost added Needs: Attention 👋 This issue needs the attention of a contributor, typically because the OP has provided an update. and removed Needs: Author Feedback The author of this issue needs to respond in order for us to continue investigating this issue. labels Dec 11, 2019

pranavkm closed this as completed Dec 11, 2019

pranavkm added the ✔️ Resolution: Duplicate Resolved as a duplicate of another issue label Dec 11, 2019

ghost added the Status: Resolved label Dec 11, 2019

pranavkm removed Needs: Attention 👋 This issue needs the attention of a contributor, typically because the OP has provided an update. Status: Resolved labels Dec 11, 2019

ghost locked as resolved and limited conversation to collaborators Jan 12, 2020

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After upgrading to .NET Standard 2.1 and Blazor v3.1.0-preview4.19579.2, Blazor WebAssembly projects no longer work. #17619

After upgrading to .NET Standard 2.1 and Blazor v3.1.0-preview4.19579.2, Blazor WebAssembly projects no longer work. #17619

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After upgrading to .NET Standard 2.1 and Blazor v3.1.0-preview4.19579.2, Blazor WebAssembly projects no longer work. #17619

After upgrading to .NET Standard 2.1 and Blazor v3.1.0-preview4.19579.2, Blazor WebAssembly projects no longer work. #17619

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