Publish does not natively handle multitargeting like Build does

[dfederm]

For a project:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFrameworks>netcoreapp2.1;net47</TargetFrameworks>
  </PropertyGroup>
</Project>

I can do msbuild (or msbuild /t:Build), and the execution will consist of an outer build which simply does an inner build for each TFM (adding a specific TargetFramework=<tfm> global property for each).

I would expect msbuild /t:Publish to behave the same way, to simply have an outer build which did an inner build for each TFM. Instead, the following error is shown:

The 'Publish' target is not supported without specifying a target framework. The current project targets multiple frameworks, please specify the framework for the published application

Why can't Publish when there are multiple TFMs just Publish for each TFM?

[livarcocc]

I believe we have a bug for this already.

cc @peterhuene

[github-actions]

Due to lack of recent activity, this issue has been labeled as 'stale'. It will be closed if no further activity occurs within 30 more days. Any new comment will remove the label.