[FIX] bus: delay the postgres notification until the transaction is committed

This is much better than committing the current transaction without notice.

addons/bus/models/bus.py

@@ -55,15 +55,15 @@ class ImBus(models.Model):
             if random.random() < 0.01:
                 self.gc()
         if channels:
-            # The notifications must be commited in database because when calling `NOTIFY imbus`, some pertinent
-            # threads will be awakened and will fetch the notification in the bus table, but since the transaction
-            # is not commited, there will be nothing to fetch, the longpolling will return empty list of notification.
-            # For some reason, this happen when `sendmany` is called more than once on the same request.
-            # `self._cr.commit()` is prevented in a test environement, to allow test rollback.
-            if not openerp.tools.config['test_enable']:
-                self._cr.commit()
-            with openerp.sql_db.db_connect('postgres').cursor() as cr2:
-                cr2.execute("notify imbus, %s", (json_dump(list(channels)),))
+            # We have to wait until the notifications are commited in database.
+            # When calling `NOTIFY imbus`, some concurrent threads will be
+            # awakened and will fetch the notification in the bus table. If the
+            # transaction is not commited yet, there will be nothing to fetch,
+            # and the longpolling will return no notification.
+            def notify():
+                with openerp.sql_db.db_connect('postgres').cursor() as cr:
+                    cr.execute("notify imbus, %s", (json_dump(list(channels)),))
+            self._cr.after('commit', notify)
 
     @api.model
     def sendone(self, channel, message):