Darc failure with .NET Core 5.0

.NET Core was recently upgrade to version 5.0 in Arcade. Due to this change, darc is now failing:

https://dev.azure.com/dnceng/internal/_build/results?buildId=630654&view=logs&j=1217766f-bb40-52a2-b66d-f8ecc3a6dc68&t=3fc062db-97f0-5cb1-4219-c99d19e79124

Version      : 2.164.0
Author       : Microsoft Corporation
Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/command-line
==============================================================================
Generating script.
Script contents:
eng\update-packagesource.cmd -gitHubPat *** -barToken *** -packagesSource F:\workspace\_work\1\s/build_stage_artifacts
========================== Starting Command Output ===========================
"C:\windows\system32\cmd.exe" /D /E:ON /V:OFF /S /C "CALL "F:\workspace\_work\_temp\f4bb586e-5b8c-4809-bd7a-2555b93b4f0a.cmd""
Adding local source to NuGet.config
Adding 'F:\workspace\_work\1\s/build_stage_artifacts' to 'F:\workspace\_work\1\s\NuGet.config'...
Updating dependencies using Darc...
GET https://dot.net/v1/dotnet-install.ps1
dotnet-install: Downloading link: https://dotnetcli.azureedge.net/dotnet/Sdk/5.0.100-preview.5.20251.2/dotnet-sdk-5.0.100-preview.5.20251.2-win-x64.zip
dotnet-install: Extracting zip from https://dotnetcli.azureedge.net/dotnet/Sdk/5.0.100-preview.5.20251.2/dotnet-sdk-5.0.100-preview.5.20251.2-win-x64.zip
dotnet-install: Adding to current process PATH: "F:\workspace\_work\1\s\.dotnet\". Note: This change will not be visible if PowerShell was run as a child process.
dotnet-install: Installation finished
Installing Darc CLI version 1.1.0-beta.20222.1...
You may need to restart your command window if this is the first dotnet tool you have installed.
'F:\workspace\_work\1\s\.dotnet\dotnet.exe' tool install microsoft.dotnet.darc --version 1.1.0-beta.20222.1 --add-source 'https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-eng/nuget/v3/index.json' -v minimal --tool-path 'F:\workspace\_work\1\s\.dotnet\tools'
  Determining projects to restore...
  Restored C:\Users\vsagent\AppData\Local\Temp\xjbkv4ig.nat\restore.csproj (in 4.6 sec).
You can invoke the tool using the following command: darc
Tool 'microsoft.dotnet.darc' (version '1.1.0-beta.20222.1') was successfully installed.
at <ScriptBlock>, F:\workspace\_work\1\s\eng\update-packagesource.ps1: line 73
at <ScriptBlock>, <No file>: line 1
It was not possible to find any compatible framework version
Cleaning up workspace...
##[error]Cmd.exe exited with code '1'.
Finishing: Update package source

[akoeplinger]

The easiest fix would be to add the following runtimeconfig.template.json to the DARC CLI project:

{
  "rollForwardOnNoCandidateFx": 2
}

This will cause the dotnet tool to try any version, not just the same major version it was compiled with (so it’d work with the new 5.0 runtime).

Other dotnet tools like coverlet, xharness are doing the same.

[missymessa]

Update package source is working for master builds of Arcade: https://dnceng.visualstudio.com/internal/_build/results?buildId=633684&view=logs&j=1217766f-bb40-52a2-b66d-f8ecc3a6dc68&t=3fc062db-97f0-5cb1-4219-c99d19e79124

Closing.