Question: How to sync templates and avoid duplicates for custom host

[GustavEikaas]

Issue with managing SDK templates for custom host - duplicates and updates

Hey folks! I'm working on a C# IDE plugin for neovim, therefore I am trying to integrate with Microsoft.TemplateEngine. I'm trying to define a custom host using Microsoft.TemplateEngine.IDE.Bootstrapper and running into some challenges around template management. Would love some guidance on the best approach here.

What I'm trying to do

I want to create my own custom host (makes sense since some templates have constraints like if!dotnet-cli), and I'd like to:

1. Automatically install all the templates that show up when running dotnet new --list
2. Avoid having duplicate versions of the same template package installed
3. Update templates when newer versions are available

The problem

I'm finding packages from the SDK at C:\Program Files\dotnet\templates\{version}\*.nupkg and installing them, but I keep running into issues with duplicates. It seems like:

• When I install packages, they get copied to C:\Users\{user}\.templateengine\packages\
• Some package identifiers include version numbers (like Microsoft.DotNet.Common.ProjectTemplates.10.0 vs Microsoft.DotNet.Common.ProjectTemplates.9.0)
• This makes it tricky to dedupe by Identifier since different major versions have different identifiers
• I'm getting stuck in a loop where certain packages (like WinForms and WPF templates) keep getting installed and then uninstalled

What I'm currently doing

// Install missing packages
var installedFilenames = installedPackages.Select(p => Path.GetFileName(new Uri(p.MountPointUri).LocalPath));
var missing = nupkgs.Where(nupkg => !installedFilenames.Contains(Path.GetFileName(nupkg)));
await bootstrapper.InstallTemplatePackagesAsync(missing, InstallationScope.Global, cancellationToken);

// Try to dedupe by Identifier
var dupes = installedPackages.GroupBy(p => p.Identifier).Where(g => g.Count() > 1);
await bootstrapper.UninstallTemplatePackagesAsync(dupes.SelectMany(g => g.Skip(1)), cancellationToken);

// Check for updates
await bootstrapper.UpdateTemplatePackagesAsync(...);

Questions

1. What's the recommended way to sync SDK templates to a custom host without creating duplicates?
2. Should I be comparing by Identifier, filename, or something else?
3. How should I handle packages where the major version is part of the identifier (like *.ProjectTemplates.9.0 vs *.ProjectTemplates.10.0)?
4. Is there a simpler/better pattern I'm missing here?

Any pointers would be super helpful! Thanks!