Regression in nuget restore for sfproj from sdk31 -> sdk60

Doing a trial run of building our repo on dotnetsdk 6.0 preview 3, and getting restore failures in a few projects. Self contained repro attached. Note that we’re currently on latest LTS sdk: 3.1.409.

It appears that dotnet restore is not processing TargetFramework correctly in 6.0 inside an old-style project (e.g. sfproj), when that sfproj has been converted to use PackageReference instead of packages.config.

This is a regression from previous (LTS) version.

Minimal repro

1. git clone https://github.com/aaronla-ms/bug-repros.git
2. cd repro-dotnetsdk6
3. setup.cmd
4. repro.cmd

expected

restore succeeds on both dotnetsdk31 and dotnetsdk60

actual

restore fails on just dotnetsdk60. Error message as follows:

Determining projects to restore… C:\repos\aaronla-ms\bug-repros\repro-dotnetsdk6\repro-dotnetsdk6.csproj : error NU1202: Package Bond.Core.CSharp 9.0.3 is not compatible with net40 (.NETFramework,Version=v4.0). Package Bond.Core.CSharp 9.0.3 supports: C:\repos\aaronla-ms\bug-repros\repro-dotnetsdk6\repro-dotnetsdk6.csproj : error NU1202: - net45 (.NETFramework,Version=v4.5) C:\repos\aaronla-ms\bug-repros\repro-dotnetsdk6\repro-dotnetsdk6.csproj : error NU1202: - net46 (.NETFramework,Version=v4.6) C:\repos\aaronla-ms\bug-repros\repro-dotnetsdk6\repro-dotnetsdk6.csproj : error NU1202: - netstandard1.0 (.NETStandard,Version=v1.0) C:\repos\aaronla-ms\bug-repros\repro-dotnetsdk6\repro-dotnetsdk6.csproj : error NU1202: - netstandard1.3 (.NETStandard,Version=v1.3) C:\repos\aaronla-ms\bug-repros\repro-dotnetsdk6\repro-dotnetsdk6.csproj : error NU1202: - netstandard1.6 (.NETStandard,Version=v1.6)

It appears that nuget.targets is incorrectly determining the project to be net40, when the project does have TargetFramework=net462 set.

versions

[git: main] aaronla@aaronla-r:repro-dotnetsdk6$ packages\dotnetsdk31\dotnet.exe --version 3.1.409

[git: main] aaronla@aaronla-r:repro-dotnetsdk6$ packages\dotnetsdk60\dotnet.exe --version 6.0.100-preview.3.21202.5

[git: main] aaronla@aaronla-r:repro-dotnetsdk6$ ver

Microsoft Windows [Version 10.0.19043.985]

[nkolev92]

NuGet/NuGet.Client#3548 looks related, which is a change in NuGet 5.8.

Beat me by 43s 😄 You are on spot, that’s where the change happened.

[nkolev92]

Discussed offline:

TargetFrameworkMoniker is what NuGet reads.

All these props have default values, so it’s possible that in some situations even setting 1 property such as TargetFrameworkVersion is sufficient to make everything work.

TargetFramework is not a property that NuGet parses, but the SDK can translate it into a valid TFM if the project is SDK based.

I’m not familiar with particular documentation around this topic.