GetReferenceNearestTargetFrameworkTask should support suppression of NU1702

[wtgodbe]

Details about Problem

https://github.com/NuGet/NuGet.Client/blob/8abf12ddde3be7bc52727f9551735fdeee7ade43/src/NuGet.Core/NuGet.Build.Tasks/GetReferenceNearestTargetFrameworkTask.cs does not read NoWarn from the project referenced (or anywhere else), so any project trying to suppress NU1702 can't do so.

NuGet product used: dotnet.exe

dotnet.exe --version (if appropriate): 3.0.100-preview4

OS version (i.e. win10 v1607 (14393.321)): Windows 10

CC @ericstj

[ericstj]

This is the AssetTargetFallback warning on ProjectReferences. It can be suppressed on PackageReference, but not on ProjectReference. The new SDK has started emiting this warning and those who treat warning as error are encountering a build failure.

[joaorosado]

Is there any workaround for this?

[ericstj]

I believe you can pass /warnAsMessage:NU1702 to whatever invokes MSBuild for you. We did that here: https://github.com/dotnet/standard/pull/1173/files#diff-02389dfac0a172ab80211625efc34318R2

[joaorosado]

Thanks, that worked.

Following that, was also able to use <MSBuildWarningsAsMessages>NU1702</MSBuildWarningsAsMessages>
as workaround to avoid only having to change 1 project, instead of all the potential build commands.

[ghost]

NU1702

OK, so where about did you add this ?