Allow copying empty directories with <Content>

This issue has been inspired by dotnet/cli#2911. In short, if I specify something like this:

<ItemGroup>
    <Content Include="logs">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>
</ItemGroup>

MSBuild will throw an error saying that the Copy task does not support copying directories. I can put in a glob, but if there are no files, nothing gets copied out (with a glob the why of that behavior is clear to me at least).

/cc @moozzyk

[WildBamboo]

Ok, so publishing in VS is sorted now, but I’m guessing the FileSystemPublish target doesn’t run when using the cli dotnet publish src\myproj.csproj --framework net462 --output "c:\temp" --configuration Release since the log folder is not present at c:\temp\logs.

So I’ve now got one target for cli/VSCode, and one for VS:

  <Target Name="CreateLogsFolderDuringCliPublish" AfterTargets="AfterPublish">
    <MakeDir Directories="$(PublishDir)logs" Condition="!Exists('$(PublishDir)logs')" />
  </Target>

  <Target Name="CreateLogsFolderDuringVSPublish" AfterTargets="FileSystemPublish">
    <MakeDir Directories="$(PublishUrl)logs" Condition="!Exists('$(PublishUrl)logs')" />
  </Target>

I can go home now 😃

[dasMulli]

However, I’m guessing the web targets would also need support for folders as items to get that out of the box - so we’re back here.

In the meantime, we can of course hook into file system publish:

<Target Name="CreateLogsFolderOnFileSystem" AfterTargets="FileSystemPublish">
  <MakeDir Directories="$(PublishUrl)Logs" Condition="!Exists('$(PublishUrl)Logs')" />
</Target>