Microsoft.NETFramework.ReferenceAssemblies not added when using NuGet static restore graph

[JoeRobich]

In Roslyn we still build some packages against net45. The .NET Framework 4.5 targeting pack is not longer installed by default (or even available) in the VS2022 installer.

We would expect if all of the following occur, then include the package:

• AutomaticallyUseReferenceAssemblyPackages is true
• The targeting pack is not known to be available at time of restore
• NuGet static restore graph is used (currently this implies the previous item)

[dsplaisted]

We can't know whether the targeting pack is always going to be available or not. It may be installed on some machines but not others.

So I think the thing to do would be to always reference the package when using static graph, instead of only doing so when it's not installed.

@cdmihai Is there a way that an MSBuild target can tell whether static graph restore is being used?

[cdmihai]

@cdmihai Is there a way that an MSBuild target can tell whether static graph restore is being used?

As far as I know there's no way to tell (@jeffkl is that correct?), and I think that's a good thing. It would be a nasty leaky abstraction to condition the rest of the build on what type of restore happened, leading to an even more brittle system.

The bigger question is why static graph restore produces different outputs than regular restore. Ideally they should not differ, and discrepancies should be marked as bugs? :)

[jeffkl]

Don't we add a global property named IsGraphBuild?

https://github.com/dotnet/msbuild/blob/main/src/Build/Graph/GraphBuilder.cs#L398

[dsplaisted]

@cdmihai @jeffkl I'm trying to write a test for this and I'm passing /graph to MSBuild, but it doesn't seem like the IsGraphBuild property is set.

How do I even run a static graph build?

[cdmihai]

How do I even run a static graph build?

Either from the command line via /graph, or programmatically via BuildManager graph APIs

@cdmihai @jeffkl I'm trying to write a test for this and I'm passing /graph to MSBuild, but it doesn't seem like the IsGraphBuild property is set.

The property should be set on the ProjectInstance objects created by the graph. These are the ones accessible via ProjectGraphNode.ProjectInstance. I do not remember how static graph restore runs the restore target. If it reuses the graph's ProjectInstances, then the property should be there. But since it's not there, it probably does not reuse them. It would be nice to reuse them, to avoid redoing evaluations.