Support common output directory root in SDK out of the box

Currently, new projects using SDK build into per-project bin and obj directories. That’s good for simple projects that don’t participate in CI. For repos that build using CI servers it is often a requirement to produce all outputs under a single root directory with following (or similar) layout:

$(RootOutputPath)\$(Configuration)\bin\$(MSBuildProjectName)
$(RootOutputPath)\$(Configuration)\obj\$(MSBuildProjectName)
$(RootOutputPath)\$(Configuration)\packages

We have seen countless repos with build systems that are customized to do so, each in a different way. Such build customization is usually hard to get right.

I propose to add an out of the box option to the SDK that allows customers to create such repo layouts trivially.

The $(RootOutputPath) could perhaps be specified via implicit Directory.Build.props import feature: https://github.com/Microsoft/msbuild/issues/222.

Perhaps we could also consider $(RepositoryRootPath) a well-known property that has a documented meaning. It’s a generally useful property to have, imo.

To summarize I propose the user has the option to set the following properties in Directory.Build.props:

<!-- Default value for configuration is set after Directory.Build.props is imported -->  
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>

<RepositoryRootPath>$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)\'))</RepositoryRootPath>
<RootOutputPath>$(RepositoryRootPath)artifacts\$(Configuration)\bin\</RootOutputPath>
<RootIntermediateOutputPath>$(RepositoryRootPath)artifacts\$(Configuration)\obj\</RootIntermediateOutputPath>

And the SDK uses these variables to set the output paths like so:

<PropertyGroup Condition="'$(RootOutputPath)' != ''" >
  <BaseOutputPath Condition="'$(BaseOutputPath)' == ''">$(RootOutputPath)$(MSBuildProjectName)\</BaseOutputPath>
  <OutputPath>$(BaseOutputPath)</OutputPath>
</PropertyGroup>

<PropertyGroup Condition="'$(RootIntermediateOutputPath)' != ''" >
  <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)' == ''">$(RootIntermediateOutputPath)$(MSBuildProjectName)\</BaseIntermediateOutputPath>
  <IntermediateOutputPath>$(BaseIntermediateOutputPath)</IntermediateOutputPath>
</PropertyGroup>

[baronfel]

Circling back here, this shipped in .NET 8.0.100 preview 3 - the easiest way to enable it is to create a Directory.Build.props file with <ArtifactsPath>$(MSBuildThisFileDirectory)artifacts</ArtifactsPath> in your repo root. You can read more about it the preview 3 and preview 4 blog post updates.

[dsplaisted]

@stijnherreman The latest update is that we are considering some output path changes in .NET 8, which would include support for a RootArtifactsPath property which would let you put all of the output of a repo under a single folder. That design is here: https://github.com/dotnet/designs/pull/281

In the meantime, you can put the following in a Directory.Build.props file to redirect the bin and obj folders of each project under a common directory:

<Project>

  <PropertyGroup>
    <RootOutputPath>artifacts</RootOutputPath>
	  
    <RootOutputPath>$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)\$(RootOutputPath)\'))</RootOutputPath>
    <BaseOutputPath>$(RootOutputPath)bin\$(MSBuildProjectName)\</BaseOutputPath>
    <BaseIntermediateOutputPath>$(RootOutputPath)obj\$(MSBuildProjectName)\</BaseIntermediateOutputPath>
  </PropertyGroup>

</Project>