Fix pagination of public repos, make more efficient and add test

data/model/modelutil.py

@@ -26,11 +26,13 @@ def paginate(query, model, descending=False, page_token=None, limit=50, id_alias
         query = query.where(model.id <= start_id)
       else:
         query = query.where(model.id >= start_id)
+  else:
+    query = query.limit(limit + 1)
 
   results = list(query)
   page_token = None
   if len(results) > limit:
-    start_id = results[limit].id
+    start_id = getattr(results[limit], id_alias or 'id')
     page_token = {
       'start_id': start_id
     }

data/model/repository.py

@@ -256,11 +256,12 @@ def get_visible_repositories(username, namespace=None, include_public=False):
   query = (Repository
            .select(Repository.name, Repository.id.alias('rid'),
                    Repository.description, Namespace.username, Repository.visibility)
-           .distinct()
            .switch(Repository)
-           .join(Namespace, on=(Repository.namespace_user == Namespace.id))
-           .switch(Repository)
-           .join(RepositoryPermission, JOIN_LEFT_OUTER))
+           .join(Namespace, on=(Repository.namespace_user == Namespace.id)))
+
+  if username:
+    # Note: We only need the permissions table if we will filter based on a user's permissions.
+    query = query.switch(Repository).distinct().join(RepositoryPermission, JOIN_LEFT_OUTER)
 
   query = _basequery.filter_to_repos_for_user(query, username, namespace, include_public)
   return query