ZSQLCatalog: prevent memory explosion when portal_catalog.getObject(None)

product/ZSQLCatalog/SQLCatalog.py

@@ -1026,6 +1026,7 @@ class Catalog(Folder,
     # It could also have a performance impact for traversals to objects in
     # the acquisition context on Zope 2.12 even when it didn't raise a weird
     # error.
+    if not uid: return None
     method = getattr(self,  self.sql_getitem_by_uid)
     search_result = method(uid = uid)
     if len(search_result) > 0: