Proposal: Unified Extension points for Imports

[Nirmal4G]

W.R.T to #1686

If we do get a Base SDK and/or a Managed SDK that's above .NET SDK, then I would propose to unify the Import Extensibility points they offer.

Base SDK props

• Directory.Build.props
• <ProjectName>.<Vendor>.Before.props

Any SDK props

• CustomBefore<SdkName>Props
• <SDK props>
• CustomAfter<SdkName>Props

Base SDK props

• <ProjectName>.<Vendor>.After.props

Project File

• CustomImportBeforeProject / CustomBefore<ProjectName> / Custom.Project.props
• <Project File>
• CustomImportAfterProject / CustomAfter<ProjectName> / Custom.Project.targets

Base SDK targets

• <ProjectName>.<Vendor>.Before.targets

Any SDK targets

• CustomBefore<SdkName>Targets
• <SDK targets>
• CustomAfter<SdkName>Targets

Base SDK targets

• <ProjectName>.<Vendor>.After.targets
• Directory.Build.targets

NOTE: Custom Before/After are user extensibility points. They are optional as they depend on the SDK implementers. MSBuildSdks already follows the Custom pattern I mentioned above.

[Nirmal4G]

Implementation Suggestions

All these could be implemented within MSBuild engine programatically, since they are unique to either the SDKs or the Project file themselves. (Breaking Change)

OR

We can put them as best practices on MSBuild Docs (issue: #2767) and add them to the official SDKs if these extension points are needed. (Safe Haven)

[Nirmal4G]

This would also enable #1045 via the <ProjectName>.<Vendor>.Before.targets!

This proposal can be augmented with #1756