WebWorkers.Issue4

This issue started as a report about an issue (#4) with SpawnDev.BlazorJS.WebWorkers but the issue may actually lie in a .Net 9 SDK build task.

Repo: WebWorkers.Issue4

Issue

The .Net 9 Blazor WASM compression build task, ApplyCompressionNegotiation, fails due to an unknown issue handling Razor Class Library Nuget packages that use <StaticWebAssetBasePath>/</StaticWebAssetBasePath> when referenced by another Razor Class Library

3 Ways To Reproduce This Issue

• Quick Start - fastest way to see the issue and a possible workaround
• Steps To Reproduce From Scratch - create projects from scratch
• Repo Demo Projects - uses this repo and demo Nuget project

Quick Start

How to demo the issue with this repo WebWorkers.Issue4: To see the issue:

• Clone repo
• Run _publish.bat in WebWorkers.Issue4 folder to do a Release publish build
• The "ApplyCompressionNegotiation" task failed unexpectedly ...

Test workaround 1:

• Uncomment <CompressionEnabled>false</CompressionEnabled> in RazorClassLibrary1.csproj
• Run _publish.bat in WebWorkers.Issue4 folder to do a Release publish build
• Build succeeded

Test workaround 2:

• Remove net9.0 from <TargetFrameworks>net8.0;net9.0</TargetFrameworks> in RazorClassLibrary1.csproj
• Run _publish.bat in WebWorkers.Issue4 folder to do a Release publish build
• Build succeeded

Steps To Reproduce From Scratch

1. Create a solution with a .Net 9 Razor Class Library (RCL) and set <StaticWebAssetBasePath>/</StaticWebAssetBasePath> in its .csproj.
2. Publish the RCL as a Nuget package (publishing locally is fine)
3. Create a new solution with an .Net 9 Razor Class Library and a .Net 9 Blazor WASM
4. In the RCL, PackageReference to the Nuget package from step 2 (a ProjectReference does not trigger the bug)
5. In the Blazor WASM app add a ProjectReference to the RCL project in the same solution
6. Run dotnet publish --nologo --configuration Release --output bin\Publish in the Blazor WASM app folder to see the error.

You get an exception similar to:

D:\users\tj\Projects\Issue4\WebWorkers.Issue4\WebWorkers.Issue4>dotnet publish --nologo --configuration Release --output "D:\users\tj\Projects\Issue4\WebWorkers.Issue4\WebWorkers.Issue4\bin\Publish\"
Restore complete (0.5s)
  RazorClassLibrary1 net9.0 succeeded (3.3s) → D:\users\tj\Projects\Issue4\WebWorkers.Issue4\RazorClassLibrary1\bin\Release\net9.0\RazorClassLibrary1.dll
  RazorClassLibrary1 net9.0 succeeded (0.1s) → D:\users\tj\Projects\Issue4\WebWorkers.Issue4\RazorClassLibrary1\bin\Release\net9.0\RazorClassLibrary1.dll
  WebWorkers.Issue4 failed with 1 error(s) and 1 warning(s) (0.6s)
    C:\Program Files\dotnet\sdk\9.0.100\Sdks\Microsoft.NET.Sdk.StaticWebAssets\targets\Microsoft.NET.Sdk.StaticWebAssets.Compression.targets(323,5): warning : Endpoints not found for compressed asset: example.JsInterop.faux.js.gz D:\users\tj\Projects\Issue4\WebWorkers.Issue4\WebWorkers.Issue4\obj\Release\net9.0\compressed\87ntuufp02-gq62o8712c.gz
    C:\Program Files\dotnet\sdk\9.0.100\Sdks\Microsoft.NET.Sdk.StaticWebAssets\targets\Microsoft.NET.Sdk.StaticWebAssets.Compression.targets(323,5): error MSB4018:
      The "ApplyCompressionNegotiation" task failed unexpectedly.
      System.InvalidOperationException: Endpoints not found for compressed asset: D:\users\tj\Projects\Issue4\WebWorkers
      .Issue4\WebWorkers.Issue4\obj\Release\net9.0\compressed\87ntuufp02-gq62o8712c.gz
         at Microsoft.AspNetCore.StaticWebAssets.Tasks.ApplyCompressionNegotiation.Execute()
         at Microsoft.Build.BackEnd.TaskExecutionHost.Execute()
         at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(TaskExecutionHost taskExecutionHost, TaskLogging
      Context taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask)
  WebWorkers.Issue4 failed (9.7s) → bin\Release\net9.0\wwwroot

Build failed with 1 error(s) and 1 warning(s) in 15.4s

7. Workaround: Disable compression (<CompressionEnabled>false</CompressionEnabled>) in the 2nd solution's Razor Class Library's .csproj and the publish will succeed and all static web assets will compress normally.

Repo Demo Projects

The projects in this repo demonstrate this bug.

WebWorkers.Issue4 - Blazor WASM App

The .Net 9 Blazor WASM project WebWorkers.Issue4 references the RCL project RazorClassLibrary1 and has compression enabled with <CompressionEnabled>true</CompressionEnabled> (default if omitted.)

RazorClassLibrary1 - RCL

RazorClassLibrary1 is a Razor Class Library that references any Nuget package RCL that uses <StaticWebAssetBasePath>/</StaticWebAssetBasePath>.
This can be a Nuget packaged RazorClassLibrary2, but it must be a PackageReference not a ProjectReference. Alternatively it can be SpawnDev.BlazorJS.WebWorkers version 2.5.22.

RazorClassLibrary2 - RCL Nuget Package

RazorClassLibrary2 is a minimal Razor Class Library to demonstrate the issue. It is a bare RCL that uses <StaticWebAssetBasePath>/</StaticWebAssetBasePath>. It needs to be packaged as a Nuget package and that package (not the project) must be referenced by RazorClassLibrary1.

RazorClassLibrary2 Alternative

To demonstrate the bug without requiring creating a Nuget package using RazorClassLibrary2, the package <PackageReference Include="SpawnDev.BlazorJS.WebWorkers" Version="2.5.22" /> (which uses <StaticWebAssetBasePath>/</StaticWebAssetBasePath>) can be referenced by RazorClassLibrary1.

Publish to see bug

Run dotnet publish --nologo --configuration Release --output bin\Publish in the WebWorkers.Issue4 folder to see the error.

Workaround

Disable compression (<CompressionEnabled>false</CompressionEnabled>) in RazorClassLibrary1.csproj and the publish will succeed and all static web assets will compress normally.

TL;DR

If you get the error Endpoints not found for compressed asset during a Blazor publish build, a possible fix is to modify your Razor Class Library's .csproj:

<PropertyGroup>
  <CompressionEnabled>false</CompressionEnabled>
</PropertyGroup>

It does not affect, or disable compression of any part of the Blazor app, but it does prevent the Endpoints not found for compressed asset error.

This issue does not exist in .Net 8 or earlier.