Support VSCode builtin GitHub authentication

[felipecrs]

VSCode now provides GitHub authentication for git even in its Terminal.

If gh had support for that too, we could have a seamless GitHub Authentication when using gh inside VSCode, which can mainly benefit vscode-dev-containers , Visual Studio Codespaces, and therefore, the upcoming GitHub Codespaces.

[mislav]

Hi thank you for letting us know! You bring up a good point that this would make it easier to get going with gh inside Codespaces. ✨

Unfortunately, I don't think we can piggy-back on VSCode authentication for our needs. First of all, that authentication is probably done via an OAuth app of their own, and we need to connect to our "GitHub CLI" OAuth app for the purposes of ocassionally getting access to some preview APIs. Second of all, we don't know which OAuth scopes does the VSCode authentication request, but since it's only git, it's probably only requests the repo scopes. CLI needs a few more scopes than that, namely read:org at least.

This is mostly just me guessing, though, and if anybody would be willing to dive into VSCode source and look up how they set up this authentication and link it here, I would be grateful!

Ref. #297

[Lewiscowles1986]

I'll be honest that workflow in VSCode broke my private key workflow, which in itself was a workaround to their git tooling being only useful for choosing which files to git add. I'm furious with them

[felipecrs]

@mislav The PR relevant on VS Code: microsoft/vscode#96069

It seems that GitHub Authentication is provided by VS Code to git CLI through GIT_ASKPASS.

[felipecrs]

If the scope of authentication provided to git isn't enough, then certainly the GitHub extension can contribute with it, since it has the required scopes.

[felipecrs]

I just had another idea: gh could support an environment variable called GH_HOSTS which is taken as a preference over ~/.config/hosts.yaml. VS Code could them create this file, fill the information (username and token) and contribute to the environment of the integrated terminal with this variable. This way, we at least don't have to fully expose GITHUB_TOKEN in an integrated terminal to make this happen.

[mislav]

gh could support an environment variable called GH_HOSTS which is taken as a preference over ~/.config/hosts.yaml

That's not a bad idea in general, but there is still the problem I outlined above: we would generally prefer if gh used a token that's tied to its own OAuth app, rather than one generated by another OAuth app. That's why I said that piggybacking on another tool's authentication mechanism could lead to limited functionality.

[ljtill]

Not the solution but in case it's useful for anyone; I've found adding a Personal Access Token in the Environment Variables (GITHUB_TOKEN) settings within VS Codespaces has solved this challenge in the short term.