SDK 3.1.401 can no longer suppress NU5104 with NoWarn

We have a dependency on a package with no release build available. Building release builds of our packages results in the NU5104 warning being issued.

Previously we were able to suppress this warning with NoWarn="NU5104" on the PackageReference. With the 3.1.401 SDK this no longer works. The exit status of dotnet pack is now 1, causing our build pipeline to fail.

A minimal reproduction is in this Gist:

https://gist.github.com/iwillspeak/2d503703a579f5623fd5e5fb410a29f1

This can be worked around by installing an older SDK (e.g. 3.1.301) in our CI pipeline, or by removing the <TreatWarningsAsErrors> property.

I can’t find any reference to this being a deliberate change. Is this a regression? How can we ignore the warning / error in this case? Ideally we would still be able to use <TreatWarningsAsErrors> for other warnings.

[nkolev92]

I finally got some time to investigate this one.

I think the root cause is that pack doesn’t respect per PackageReference NoWarn.

Now that behavior is not a regression. It’s always been broken/not supported.

The reason why it appeared to work before was because pack always returned an exit code 0 and I fixed that in 3.1.400, https://github.com/NuGet/NuGet.Client/pull/3367.

I will move this issue to NuGet/Home, but for now the recommendation is suppress it globally.

[chipplyman]

This is closed as complete, but I see no metadata or comments telling me which version has the fix.