Static web assets have different 'ContentRoot' metadata values when packing Blazor project.

[montyclt]

Describe the bug

Error when packing Blazor webassembly application that has static assets (wwwroot) and reference to RCL package with static assets.

The error appear after updating from Blazor Webassembly Preview 1 to Preview 3, and remain after updating to Preview 4.

The reason why I pack my Blazor app into NuGet package is because it is the core of my application, and you can develop extensions referencing the core application. Today it is not implemented, but the idea is add the ability of loading extensions at runtime using reflection.

To Reproduce

1. Add reference to RCL package that include Razor components.
2. Add wwwroot files to your Blazor application.
3. Remove manually obj and bin folders. (optionally, the error happens doing it and without doing it)
4. Build.
5. Pack your Blazor application into NuGet package.

If I remove my wwwroot folder or I remove reference to Blazored.Typeahead, then I can pack it without any problems.

Severity	Code	Description	Project	File	Line	Suppression State
Error		Static web assets have different 'ContentRoot' metadata values 'C:\Users\Trabajo\source\repos\core\Vadavo.Vicim.Core.Blazor\wwwroot' and 'C:\Users\Trabajo\source\repos\core\Vadavo.Vicim.Core.Blazor\bin\Debug\netstandard2.1\wwwroot' for 'C:\Users\Trabajo\source\repos\core\Vadavo.Vicim.Core.Blazor\wwwroot\css\open-iconic\FONT-LICENSE' and 'C:\Users\Trabajo\source\repos\core\Vadavo.Vicim.Core.Blazor\obj\Debug\netstandard2.1\blazor\unlinked\Vadavo.Vicim.Core.Blazor.dll'.	Vadavo.Vicim.Core.Blazor	C:\Program Files\dotnet\sdk\3.1.201\Sdks\Microsoft.NET.Sdk.Razor\build\netstandard2.0\Microsoft.NET.Sdk.Razor.StaticWebAssets.targets	415

Further technical details

• ASP.NET Core version: Blazor webassembly 3.2 Preview 3 and 4
• Include the output of dotnet --info:

PS C:\Users\Trabajo> dotnet --info
SDK de .NET Core (reflejando cualquier global.json):
 Version:   3.1.201
 Commit:    b1768b4ae7

Entorno de tiempo de ejecución:
 OS Name:     Windows
 OS Version:  10.0.18363
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.1.201\

Host (useful for support):
  Version: 3.1.3
  Commit:  4a9f85e9f8

.NET Core SDKs installed:
  3.1.201 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

• The IDE (VS / VS Code/ VS4Mac) you're running on, and it's version: The error happens in Visual Studio 16.5.4 in Windows and dotnet cli in Ubuntu (docker, CI/CD deployment)
• csproj file:

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netstandard2.1</TargetFramework>
    <RazorLangVersion>3.0</RazorLangVersion>
    <IsPackable>true</IsPackable>
    <Version>1.1.17-beta</Version>
    <BlazorWebAssemblyEnableLinking>false</BlazorWebAssemblyEnableLinking>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="System.Net.Http.Json" Version="3.2.0-preview5.20210.3" />
    <PackageReference Include="Blazored.Typeahead" Version="4.3.0" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="3.2.0-preview4.20210.8" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.Build" Version="3.2.0-preview4.20210.8" PrivateAssets="all" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="3.2.0-preview4.20210.8" PrivateAssets="all" />
    <PackageReference Include="Microsoft.AspNetCore.Components.Authorization" Version="3.1.1" />
    <PackageReference Include="Microsoft.AspNetCore.WebUtilities" Version="2.2.0" />
    <PackageReference Include="MontyClt.Bui" Version="1.0.8-alpha" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\Vadavo.Vicim.Core.Client\Vadavo.Vicim.Core.Client.csproj" />
  </ItemGroup>

</Project>

• Project structure:
  

[montyclt]

As temporally workaround, I moved the wwroot directory to Vadavo.Vicim project that is a ASP.NET Core server app that host the Blazor webassembly application, but I don't like it as solution.

[javiercn]

@montyclt thanks for contacting us.

Packing blazor webassembly applications as nuget packages is not a feature we support.

[montyclt]

@montyclt thanks for contacting us.

Packing blazor webassembly applications as nuget packages is not a feature we support.

Hi Javier, thanks for your response. That was working on Preview 1.