[FIX] account_payment_order: always return a string in the _get_payment_order_communication

account_payment_order/models/account_move.py

@@ -43,7 +43,7 @@ class AccountMove(models.Model):
         """
         Retrieve the communication string for the payment order
         """
-        communication = self.payment_reference or self.ref or self.name or ""
+        communication = self.payment_reference or self.ref or self.name
         if self.is_invoice():
             if (self.reference_type or "none") != "none":
                 communication = self.ref
@@ -62,7 +62,7 @@ class AccountMove(models.Model):
                 ]
             )
             communication += " " + " ".join(references)
-        return communication
+        return communication or ""
 
     def _prepare_new_payment_order(self, payment_mode=None):
         self.ensure_one()

account_payment_order/tests/test_payment_order_outbound.py

@@ -281,6 +281,28 @@ class TestPaymentOrderOutbound(TestPaymentOrderOutboundBase):
         self.invoice.payment_reference = "R1234"
         self.assertEqual("F1242", self.invoice._get_payment_order_communication())
 
+    def test_invoice_communication_03(self):
+        self.invoice.ref = False
+        self.invoice.action_post()
+        self.assertEqual("", self.invoice._get_payment_order_communication())
+        reverse_wizard = Form(
+            self.env["account.move.reversal"].with_context(
+                active_ids=self.invoice.ids, active_model=self.invoice._name
+            )
+        )
+        reverse = reverse_wizard.save()
+        reverse_res = reverse.reverse_moves()
+        reverse_move = self.env[reverse_res["res_model"]].browse(reverse_res["res_id"])
+        self.assertEqual(
+            " %s" % reverse_move.ref,
+            self.invoice._get_payment_order_communication(),
+        )
+        self.invoice.ref = "ref"
+        self.assertEqual(
+            "ref %s" % reverse_move.ref,
+            self.invoice._get_payment_order_communication(),
+        )
+
     def test_manual_line_and_manual_date(self):
         # Create payment order
         outbound_order = self.env["account.payment.order"].create(