Make sure to return / and not empty string for stuff on domain root

src/yunohost/app.py

@@ -455,6 +455,8 @@ def app_map(app=None, raw=False, user=None):
                 perm_domain, perm_path = perm_url.split("/", 1)
                 perm_path = "/" + perm_path.rstrip("/")
 
+            perm_path = perm_path if perm_path != "" else "/"
+
             return perm_domain, perm_path
 
         this_app_perms = {p: i for p, i in permissions.items() if p.startswith(app_id + ".") and i["url"]}
@@ -490,7 +492,6 @@ def app_map(app=None, raw=False, user=None):
                 continue
 
             perm_domain, perm_path = _sanitized_absolute_url(perm_info["url"])
-
             if perm_name.endswith(".main"):
                 perm_label = label
             else:
@@ -1362,11 +1363,12 @@ def app_makedefault(operation_logger, app, domain=None):
     elif domain not in domain_list()['domains']:
         raise YunohostError('domain_unknown')
 
-    operation_logger.start()
     if '/' in app_map(raw=True)[domain]:
         raise YunohostError('app_make_default_location_already_used', app=app, domain=app_domain,
                             other_app=app_map(raw=True)[domain]["/"]["id"])
 
+    operation_logger.start()
+
     # TODO / FIXME : current trick is to add this to conf.json.persisten
     # This is really not robust and should be improved
     # e.g. have a flag in /etc/yunohost/apps/$app/ to say that this is the
@@ -1636,6 +1638,8 @@ def app_ssowatconf():
                 perm_domain, perm_path = perm_url.split("/", 1)
                 perm_path = "/" + perm_path.rstrip("/")
 
+            perm_path = perm_path if perm_path != "" else "/"
+
             return perm_domain + perm_path
 
         # Skipped