[abhinavgautam01]

Closes #47

Summary

Adds GetAuthenticatedUser(ctx) (*forge.User, error) to the Forge interface. It returns the profile of the user the client's token belongs to. This lets apps that sign users in with OAuth show the user's username, name, avatar and email without calling each forge's API themselves.

It returns the existing forge.User type, so there are no new types.

Per-backend behaviour

Backend	Endpoint	Fields returned
GitHub	GET /user	Login, Name, Email, AvatarURL, HTMLURL
GitLab	GET /api/v4/user	Login, Name, Email, AvatarURL, HTMLURL
Gitea / Forgejo	GET /api/v1/user	Login, Name, Email, AvatarURL, HTMLURL
Bitbucket	GET /2.0/user	Login, Name, AvatarURL, HTMLURL
Gerrit	GET /accounts/self (/a/accounts/self when a token is set)	Login, Name, Email
Tangled	none	ErrNotSupported
GitLab under TinyGo	none	the existing TinyGo ErrNotSupported error

Notes:

• Bitbucket: Email is left empty because Bitbucket only returns email addresses from the separate /user/emails endpoint.
• Gerrit: uses the same account conversion as change owners and authors, so the login falls back to the email and then the account ID when there is no username.
• Gitea: uses the SDK's GetMyUserInfo, the same way the other Gitea services call the SDK. The SDK call takes no context.
• Errors: auth failures (for example a missing or expired token) come back as each backend's usual error. Nothing is wrapped or hidden.

Compatibility

This adds a method to the Forge interface, so code outside this repo that implements Forge needs to add it, the same as when GetRateLimit was added. The in-repo mocks in forges_test.go and internal/cli/pr_checkout_test.go are updated.

Tests

• GitHub, GitLab, Gitea, Bitbucket and Gerrit each get a test against a fake server. Each test checks the endpoint path and every field mapped into forge.User. The GitLab, Gitea, Bitbucket and Gerrit tests also check that the token is sent in that forge's auth header.
• GitHub and Bitbucket also have a 401 test, which checks that a failed login comes back as an error.
• The Tangled test checks that it returns ErrNotSupported.
• TestTinyGoServicesReturnUnsupported now covers GetAuthenticatedUser.
• go test -race ./..., go test -tags=tinygo ./gitlab, the js/wasm and wasip1 builds and golangci-lint v2.14.0 all pass locally.

[andrew]

Thanks, the shape is right and the per-backend tests are thorough. Two changes before merging.

[abhinavgautam01]

Thanks! Both changes are pushed: Gitea errors go through wrapErr (with a 401 test) and convertAccount is now a package-level function. Tests, lint and the wasm builds pass locally.