Install .NET 6.0.x runtime. Remove DotNetCoreVersion param. Undo DOTNET_ROLL_FORWARD.

[konrad-jamrozik]

Update 2/10/2023

This PR got reverted by

• Revert "Install .NET 7.0.x from global.json and .NET 6.0.0 runtime. Remove DotNetCoreVersion param. (#5395)" #5398

and then redone by

• Install .NET 6.0.x SDK. Remove DotNetCoreVersion param. Undo DOTNET_ROLL_FORWARD - take 2 #5405

---

Changes made per this comment:

• Update .NET from 6.0.403 to 7.0.102 + DOTNET_ROLL_FORWARD: Major + fix wrong quotes in install-net.yml #5379 (comment)

and my discussion with @weshaggard

We were already using the newest .NET SDK to build things; it comes from global.json. But with this PR, we also install .NET 6.0.x runtime, so that our tooling targeting it runs against it.

A note on parameter support

I have removed DotNetCoreVersion because:

• Setting global.json .NET to 6.0.x and trying to override with DotNetCoreVersion 7.0.x does not work (<- this may not be true, but we want to have newest .NET in global.json anyway).
• Setting global.json .NET to 7.0.x and overriding with DotNetCoreVersion 6.0.x would work, but then the parameter would have to be passed in many places, as most of our tools target 6.0.x.
• We could change the DotNetCoreVersion to something like SkipRuntimeInstall; in such case, the .NET 6.0.x would be installed by default, but then for tools migrated to 7.0.x one could skip it by passing SkipRuntimeInstall. Once all tools are migrated to 7.0.x we could update this file to no longer install 6.0.x runtime and get rid of all such SkipRuntimeInstall arguments. However, this seems to me as some amount of work not necessarily worth the effort.

Having said that, once we need more flexibility for the runtimes installed, we could add the param back.

Testing done

This build confirms that an assembly targeting 7.0.x works (I made Azure.Sdk.Tools.RetrieveCodeOwners and Azure.Sdk.Tools.CodeOwnsersParser target 7.0.0 for this build):

• https://dev.azure.com/azure-sdk/internal/_build/results?buildId=2177144&view=results

This build confirms that an assembly targeting 6.0.x works:

• https://dev.azure.com/azure-sdk/internal/_build/results?buildId=2177181&view=logs&s=c0a22914-42ba-51eb-e68d-84c64519cae1

[weshaggard]

I was expecting to see this on the SDK install above. Did you try to verify if we need to explicitly have this step for the 6 runtime?

[konrad-jamrozik]

Per our chat, these builds show the behavior on performMultiLevelLookup for SDK:

(source)

For 6.0 target (fails):

• https://dev.azure.com/azure-sdk/internal/_build/results?buildId=2177201&view=logs&j=951e43bb-1e6d-59fb-d232-79b6dbbdcd74&t=3c49b6ca-e856-54cd-c01f-bfd23f6f6d30&l=22

For 7.0 target (works):

• https://dev.azure.com/azure-sdk/internal/_build/results?buildId=2177200&view=results