maui: Can't publish a Maui app that references a class library on Windows without modifying the project

Description

A Maui app that references a class library can’t be published without modifying the project file using the following command:

msbuild /restore /t:Publish /p:TargetFramework=net6.0-windows10.0.19041 /p:TargetFrameworks="net6.0-windows10.0.19041;net6.0" /p:configuration=release /p:GenerateAppxPackageOnBuild=true /p:AppxPackageSigningEnabled=true /p:PackageCertificateThumbprint="YOUR_CERT_THUMBPRINT_HERE" /p:PackageCertificatePassword="AnyTestPasswordYouLike"

Steps to reproduce

1. Create a Maui application.
2. Create a class library.
3. Reference the class library from the Maui application.
4. Open a developer command prompt.
5. Navigate to the Maui app folder.
6. Run the command above to publish the app.

Workaround

• Update the project file with the following changes

  -               <TargetFrameworks>net6.0-android;net6.0-ios;net6.0-maccatalyst</TargetFrameworks>
  -               <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows'))">$(TargetFrameworks);net6.0-windows10.0.19041.0</TargetFrameworks>
  +               <TargetFramework>net6.0-windows10.0.19041.0</TargetFramework>
  

• Update the command to use the following:

  msbuild /restore /t:Publish /p:configuration=Release /p:GenerateAppxPackageOnBuild=true /p:AppxPackageSigningEnabled=true /p:PackageCertificateThumbprint="<<YOURTHUMBPRINTHERE>>" /p:PackageCertificatePassword="AnyTestPasswordYouLike"