Header Login and Register buttons ignore the login and register route roles #305

Description

The shell header's Login and Register buttons link straight to LMS URLs taken from site config, ignoring the org.openedx.frontend.role.login and org.openedx.frontend.role.register route roles. When @openedx/frontend-app-authn is installed as an app, clicking Login in the header still sends the user off to the legacy LMS login page instead of navigating to the Authn app's /authn/login route.

LoginButton renders href={config.loginUrl} in shell/header/anonymous-menu/LoginButton.tsx, and RegisterButton builds ${config.lmsBaseUrl}/register in shell/header/anonymous-menu/RegisterButton.tsx. Neither consults the routes registered by the apps in the site config.

This is inconsistent with the rest of the runtime. runtime/routing/authenticatedLoader.ts resolves the login destination with getUrlByRouteRole() first and only falls back to config.loginUrl when no app provides that role, which is why a redirect from a protected route correctly lands on the Authn app while the header button does not.

An LMS-side redirect can mask the problem, since /login redirects to AUTHN_MICROFRONTEND_URL when ENABLE_AUTHN_MICROFRONTEND is enabled. That is still a full page round trip out to the LMS and back rather than an in-app navigation, and it fails outright on deployments where the redirect is not configured.

Proposed solution

Make both buttons role-aware, preserving the current site config values as fallbacks so behavior is unchanged for sites that do not install the Authn app. LoginButton should use getUrlByRouteRole('org.openedx.frontend.role.login') and fall back to config.loginUrl; RegisterButton should use getUrlByRouteRole('org.openedx.frontend.role.register') and fall back to ${config.lmsBaseUrl}/register.

Because a resolved role URL can be either an internal path or an external route URL, the buttons should also navigate internally when the resolved value is a relative path, so that the SPA handles it rather than triggering a full page load. The same treatment likely applies anywhere else in the shell that links to authentication destinations.

LLM usage notice

Built with assistance from Claude.