Incorrect SDK version used when multiple SDKs are installed

The version detection logic in tools.sh/ps1 will use a globally installed “dotnet” if the install directory contains the SDK version requested in global.json.

If there are multiple SDKs installed (one that happens to match the requested version), this can result in using a version later than the one requested. Together with https://github.com/dotnet/arcade/issues/3763 this was resulting in local builds of coreclr using an incorrect SDK version in some cases.

[dagood]

It sounds like Arcade is inconsistently blocking roll-forward: (I guess because of the “is .NET Core installed?” capability test)

If the roll-forward is desired, I’d expect it to be independent of whether I happen to have a global install of the version listed in global.json.

[sbomer]

@chcosta I only saw this in local builds (and I’m guessing the official/ci builds won’t run into this because they probably don’t have any newer SDKs installed globally).

For example, coreclr currently uses 3.0.100-preview7-012821, and I have a global install of version 5.0.100-alpha1-013789. When I run, for example ./eng/common/msbuild.sh src/build.proj, it uses version 3.0.100-preview7-012821 as expected. However, if I then install 3.0.100-preview7-012821 globally, the same command starts using 5.0.100-alpha1-013789 from the global install. If the roll-forward is desired, I’d expect it to be independent of whether I happen to have a global install of the version listed in global.json.

If I get rid of use_installed_dotnet_cli from coreclr’s eng/configure-toolset.sh, I see the same behavior with build.sh (this is on an empty project, but it illustrates the issue):

>  ./eng/common/build.sh --projects `pwd`/eng/empty.csproj --build -v diag

Without a global install of 3.0.100-preview7-012821:

...
Target "CoreBuild: (TargetId:83)" in file "/Users/sven/src/dotnet/coreclr/.dotnet/sdk/3.0.100-preview7-012821/Microsoft.Common.CurrentVersion.targets"
...

With a global install of 3.0.100-preview7-012821:

...
Target "Build: (TargetId:83)" in file "/Users/sven/bin/sdk/5.0.100-alpha1-013789/Microsoft.Common.CurrentVersion.targets
...