VS Code: The prompt box to add the required assets (launch.json & task.json) cannot be automatically popped up with the 5.0/3.1/2.1 projects in latest C# Extension

[MMtwo]

Azure DevOps work item: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1546000

Testcases Affected

VerifyReactAndReduxTemplate

Platform

• [X] Windows
• [X] macOS
• [X] Linux

Repro Steps

1. Create a ReactRedux project in the Command Prompt:

   md Redux
   cd Redux
   dotnet new reactredux -f netcoreapp3.1

2. Open project using VS Code:

   code .

3. Install the required C# Extension [v1.25.0]

Note:

1. It works well on June Servicing SDK 6.0.x + C# Extension [v1.25.0]
2. It works well on June Servicing SDK 3.1.x + C# Extension [v1.24.4]
3. This issue also reproduces on Linux/Mac.

Actual Result

The prompt box to add the required assets (launch.json & task.json) cannot be automatically popped up in VS Code with an error .

Expected Result The prompt box to add the required assets (launch.json & task.json) will be automatically popped up in VS Code.

Error Log

OmniSharp requires an install of the .NET SDK provide language services when 'omnishrp.useModernNet' is enabled in Settings. Please install the latest .NET and restarting vscode, you may need to log out and log back in or restart your system for changes to the PATH to take effect.

[MMtwo]

This issue is copy from https://github.com/aspnet/AspNetCore-ManualTests/issues/1383

[phil-allen-msft]

From the content here-in, this appears to be an issue that is better addressed from within the https://github.com/OmniSharp/omnisharp-vscode repo. Please open a new issue in that repo.

[MMtwo]

Yeah, this issue is similar to https://github.com/OmniSharp/omnisharp-vscode/issues/5509, and it can be resolved through setting and search for "omnisharp use modern Net" and uncheck it.