fix: Handle a case that could cause infinite redirects.

If ENABLE_MKTG_SITE is True, MKTG_URLS['ROOT'] must be set.  However if
it is set to the same value as the LMS_ROOT_URL (which points to this
view), you can end up in an infinite redirect loop.  If the two URLs do
match, don't redirect, just fall through to the content that this page
would have responded with instead.

Author: feanil

lms/djangoapps/branding/tests/test_views.py

@@ -269,6 +269,20 @@ def test_index_does_not_redirect_without_site_override(self):
         response = self.client.get(reverse("root"))
         assert response.status_code == 200
 
+    @override_settings(ENABLE_MKTG_SITE=True)
+    @override_settings(MKTG_URLS={'ROOT': 'https://foo.bar/'})
+    @override_settings(LMS_ROOT_URL='https://foo.bar/')
+    def test_index_wont_redirect_to_marketing_root_if_it_matches_lms_root(self):
+        response = self.client.get(reverse("root"))
+        assert response.status_code == 200
+
+    @override_settings(ENABLE_MKTG_SITE=True)
+    @override_settings(MKTG_URLS={'ROOT': 'https://home.foo.bar/'})
+    @override_settings(LMS_ROOT_URL='https://foo.bar/')
+    def test_index_will_redirect_to_new_root_if_mktg_site_is_enabled(self):
+        response = self.client.get(reverse("root"))
+        assert response.status_code == 302
+
     def test_index_redirects_to_marketing_site_with_site_override(self):
         """ Test index view redirects if MKTG_URLS['ROOT'] is set in SiteConfiguration """
         self.use_site(self.site_other)

lms/djangoapps/branding/views.py

@@ -42,23 +42,25 @@ def index(request):
         # page to make it easier to browse for courses (and register)
         if configuration_helpers.get_value(
                 'ALWAYS_REDIRECT_HOMEPAGE_TO_DASHBOARD_FOR_AUTHENTICATED_USER',
-                getattr(settings,'ALWAYS_REDIRECT_HOMEPAGE_TO_DASHBOARD_FOR_AUTHENTICATED_USER', True)):
+                getattr(settings, 'ALWAYS_REDIRECT_HOMEPAGE_TO_DASHBOARD_FOR_AUTHENTICATED_USER', True)):
             return redirect('dashboard')
 
     if use_catalog_mfe():
         return redirect(f'{settings.CATALOG_MICROFRONTEND_URL}/', permanent=True)
 
     enable_mktg_site = configuration_helpers.get_value(
         'ENABLE_MKTG_SITE',
-        getattr(settings,'ENABLE_MKTG_SITE', False)
+        getattr(settings, 'ENABLE_MKTG_SITE', False)
     )
 
     if enable_mktg_site:
         marketing_urls = configuration_helpers.get_value(
             'MKTG_URLS',
             settings.MKTG_URLS
         )
-        return redirect(marketing_urls.get('ROOT'))
+        root_url = marketing_urls.get("ROOT")
+        if root_url != getattr(settings, "LMS_ROOT_URL", None):
+            return redirect(root_url)
 
     domain = request.headers.get('Host')