dotnet cli passing -target:Restore to MSBuild instead of -restore

As seen in: https://github.com/xamarin/net6-samples/pull/52

We have a multi-targeted project with:

<TargetFrameworks>net6.0-android;net6.0-ios</TargetFrameworks>

To deploy to an Android device/emulator (and not iOS), you can run:

> dotnet build -t:Run -p:TargetFramework=net6.0-android

With .NET 6.0.100-alpha.1.21064.27, this command fails with:

error MSB4057: The target "Run" does not exist in the project.

The MSBuild arguments the dotnet cli is passing seem odd:

-target:Restore -t:Run

With .NET 6.0.100-alpha.1.20562.2, it used to pass:

-restore -t:Run

In fact, you can workaround the problem by doing:

> dotnet build -t:Run -p:TargetFramework=net6.0-android --no-restore

I tried creating other, simpler projects to reproduce this issue, but a console app with TargetFrameworks=net5.0;net6.0 works fine. I always see -restore being passed.

I think it is something to with .NET workloads and multi-targeting at the same time?

• Example broken log: broken.zip
• Example working log: works.zip

[dsplaisted]

@sfoslund Could you work on fixing this? I tried, but ran into issues where an argument such as -t:Run got interpreted as the SlnOrProjectArgument by the parser, and thus wasn’t handled correctly by RestoringCommand.

Here is the change I made, which added some test coverage and tried to fix RestoringCommand: https://github.com/dsplaisted/sdk/commit/ad79b3f866829dba3ca4dd35e6edd3897b7bd460

[dsplaisted]

So theoretically I think switching to system.commandline “fixed” this bug in that now we try to use a separate restore command when the target framework is specified on the command line. However, this has created a bug here such that we pass the -t:run option to the separate restore command and it fails because we didn’t specify a target framework.

It seems like Sarah was correct here. Fixing one bug (It sounds like RestoringCommand wasn’t correctly detecting when it needed to run a separate restore command) exposed another bug. The new bug is that additional targets specified (such as Run) get passed through to the restore command, when they should be filtered out and only passed to the actual command run after the restore.