[release/3.1] Switch to using 3.1100 SDK to build 3.1

[mmitche]

Required for upstack components, so this is for consistency.

[mmitche]

@Anipik @ericstj @wtgodbe A ton of errors upgrading the sdk here. What do I need to do?

F:\workspace\_work\1\s\.dotnet\sdk\3.1.100\Microsoft.Common.CurrentVersion.targets(2106,5): error MSB3245: Could not resolve this reference. Could not locate the assembly "System.Runtime". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors. [F:\workspace\_work\1\s\src\System.Security.Cryptography.Pkcs\ref\System.Security.Cryptography.Pkcs.csproj]
##[error].dotnet\sdk\3.1.100\Microsoft.Common.CurrentVersion.targets(2106,5): error MSB3245: (NETCORE_ENGINEERING_TELEMETRY=Build) Could not resolve this reference. Could not locate the assembly "System.Runtime". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors.

[wtgodbe]

Taking a look, @safern @joperezr @ViktorHofer may also know

[wtgodbe]

These errors are in System.Windows.Extensions, System.Drawing.Common, and System.Security.Cryptography.{xxxxx}, which look suspiciously similar to the set of packages we built in 3.0.1:

corefx/src/packages.builds

Lines 28 to 37 in b7c9ada

	<!-- add specific builds / pkgproj's here to include in servicing builds -->
	<Project Include="$(MSBuildThisFileDirectory)..\pkg\Microsoft.Windows.Compatibility\Microsoft.Windows.Compatibility.builds">
	<AdditionalProperties>$(AdditionalProperties)</AdditionalProperties>
	</Project>
	<Project Include="$(MSBuildThisFileDirectory)System.Drawing.Common\pkg\System.Drawing.Common.pkgproj">
	<AdditionalProperties>$(AdditionalProperties)</AdditionalProperties>
	</Project>
	<Project Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Cng\pkg\System.Security.Cryptography.Cng.pkgproj">
	<AdditionalProperties>$(AdditionalProperties)</AdditionalProperties>
	</Project>

. Looking into if we need to update the baseline or harvestPackages.props

[ericstj]

Looking into if we need to update the baseline or harvestPackages.props

That's not the problem, this should be coming from netcoreapp.depproj.

These all target netcoreapp3.0: did the 3.1 SDK drop support for targeting netcoreapp3.0? @ViktorHofer was facing something similar in dotnet/runtime repo.

[mmitche]

Looking into if we need to update the baseline or harvestPackages.props

That's not the problem, this should be coming from netcoreapp.depproj.

These all target netcoreapp3.0: did the 3.1 SDK drop support for targeting netcoreapp3.0? @ViktorHofer was facing something similar in dotnet/runtime repo.

A quick check of targeting nca3.0 in a simple console app worked for me.

[ericstj]

I found the problem but am currently pulled away from my machine. Will get back to it shortly.

[ericstj]

This should be fixed. FYI @joperezr I removed the condition you added in 9fe02e8 since we don't seem to need it and it was causing copy to be skipped in this case. @ViktorHofer I believe this addresses the comment I made here: dotnet/runtime#445 (comment) and likely the root cause of dotnet/runtime#121

[ericstj]

Looks like we still need that condition, I will see how to make it work in both cases.

[ericstj]

@mmitche should be good. Merge at your liesure. (not sure the state of the branches ATM)