Also avoid to have '/' on move line label of supplier invoices

account_usability/migrations/8.0.0.3/pre-migration.py

@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+# © 2016 Akretion (Alexis de Lattre <alexis.delattre@akretion.com>)
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+def migrate(cr, version):
+    if not version:
+        return
+
+    # cf the inherit of action_number() of account.invoice
+    # in account_usability/account.py
+    cr.execute(
+        "UPDATE account_move_line SET name=account_move.name "
+        "FROM account_move WHERE account_move_line.move_id = account_move.id "
+        "AND account_move_line.name='/' "
+        "AND account_move_line.journal_id in "
+        "(SELECT id FROM account_journal WHERE type in ('purchase', 'purchase_refund'))")