[Issue] ai agent extension fails to init agent.yaml with failed to parse GitHub URL could not find a valid branch in url path

[therealjohn]

Goal

Developers get relevant error message and actionable suggestion when init -m fails because the Github URL is private or in an EMU repo and the gh CLI is not authorized for that organization.

Context

• An agent manifest file might be stored in a private repo or EMU repo which causes a cryptic error about being unable to parse a GitHub URL. Here's an example image:

• Using --debug flag uncovers: gh: Resource protected by organization SAML enforcement. You must grant your Personal Access token access to this organization. (HTTP 403)

Desired behavior

Gracefully handle auth errors from gh by printing a structured error message like:
"The GitHub URL is protected by organization SAML enforcement. You must grant your Personal Access token access to this organization."

And provide an error suggestion like:

"Suggestion: Run gh auth login and select the Authorize button next to the organization that contains this repository. If you're using GITHUB_TOKEN to authenticate instead, modify the token in your GitHub settings by updating in the 'Configure SSO' setting for the correct organization."

Implementation Notes

• Use structured errors and suggestions consistent with the rest of the codebase

Acceptance Criteria

• Unit tests added or updated
• Existing test suite passes
• Lint and format passes

How to test

azd ai agent init -m "https://github.com/coreai-microsoft/hosted-agents-bugbash/blob/main/samples/python/agentserver-responses/background-agent/agent.manifest.yaml"

This repo requires an EMU account and should produce a relevant error message and suggestion without the proper authentication.

[rajeshkamal5050]

@trangevi @JeffreyCA isn't this fixed with #6631??

[trangevi]

Not necessarily, that commit just makes it so that we won't fail if the user isn't logged in but the repo doesn't need auth. This issue seems to be more a matter of not properly surfacing the actual underlying error, which in this case is missing access.

That debug error which is called out needs to be surfaced up by the extension framework, instead of just saying it can't find a branch.

[trangevi]

@rajeshkamal5050 , I checked this as we discussed in the sync this morning, the error is coming from core, gh_source.go. Is this something which could be prioritized, as we've gotten more people reporting it due to recent testing