Remove dotnet-new3

[MiYanni]

Summary

I don't know the full history of this project, but AFAIK, dotnet-new3 isn't actually part of the product (.NET SDK). It was some kind of attempt at changing the mechanics of dotnet new. Looking at the dotnet/templating repo, there was a v1 of dotnet new and a v2 of dotnet new, which I believe to be the current version we ship. The only mention of new3 in the dotnet/templating repo now is in some docs. I searched for dotnet-new3 in GitHub search and only found mentions from forks of either the dotnet/sdk or dotnet/templating repos.

From what I can tell, we didn't use dotnet-new3 for anything in this repo. It hasn't had any actual code changes since 2022. The templating handoff PowerPoint didn't mention it either.

This is part of the effort to clean up cruft, prior to larger CLI changes.

Copilot reviewed 20 out of 20 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (8)

src/Cli/dotnet-new3/Program.cs:1

• Ensure that all project and build configuration files have been updated to remove references to dotnet-new3/Program.cs so that its removal does not break any build or runtime dependencies.

// Removed Program.cs from dotnet-new3

src/Cli/dotnet-new3/ParserFactory.cs:1

• Confirm that any build or dependency references to dotnet-new3/ParserFactory.cs have been removed from the solution to avoid compile-time errors.

// Removed ParserFactory.cs from dotnet-new3

src/Cli/dotnet-new3/New3CommandFactory.cs:1

• Verify that the removal of dotnet-new3/New3CommandFactory.cs is fully supported by updating any command registration or configuration files.

// Removed New3CommandFactory.cs from dotnet-new3

src/Cli/dotnet-new3/HostFactory.cs:1

• Make sure that any references to dotnet-new3/HostFactory.cs in project files or dependency injection setups are removed to prevent runtime failures.

// Removed HostFactory.cs from dotnet-new3

src/Cli/dotnet-new3/Dotnet.cs:1

• Ensure that the removal of dotnet-new3/Dotnet.cs does not leave dangling calls or references in any build scripts or tests.

// Removed Dotnet.cs from dotnet-new3

src/Cli/dotnet-new3/CompleteCommand.cs:1

• Double-check that removal of dotnet-new3/CompleteCommand.cs is intentional and that no CLI completion functionality is inadvertently affected.

// Removed CompleteCommand.cs from dotnet-new3

src/Cli/dotnet-new3/BuiltInTemplatePackagesProvider.cs:1

• Confirm that all registrations or usages of built-in template package providers now come from the correct source and that this removal does not break any template discovery logic.

// Removed BuiltInTemplatePackagesProvider.cs from dotnet-new3

src/Cli/dotnet-new3/ArgumentEscaper.cs:1

• Verify that no other components depend on dotnet-new3/ArgumentEscaper.cs and that any shared functionality has been correctly migrated or removed.

// Removed ArgumentEscaper.cs from dotnet-new3

[Forgind]

I (perhaps naively) tried dotnet new3 -? and got an error. Is there any way to actually call into this code? If not, then I 100% support this.