[IMP] stock_picking_invoicing: set reversed_entry in return pick invoicing

[DiegoParadeda]

This PR automatically references a picking's invoice in it's return invoice using the field reversed_entry_id

Stock Move  --->  Invoice 1
     |
     v
Return Stock Move  --->  Invoice 2 (references Invoice 1)


e.g. invoice_2.reversed_entry_id = invoice_1

[mbcosta]

Thank you @DiegoParadeda for your PR, some points about:

• Why not infom the field reversed_entry_id inside the method def _build_invoice_values_from_pickings ? It's seems the right place even to be inherit

• Should we consider include the move_lines.origin_returned_move_id.picking_id as a KEY in def _get_picking_key because in this case there are no Grouped Invoice as reversed_entry_id is a Many2One ?

• Are you sure about the necessity to change the Origin Invoice with def get_return_origin_invoice_ids? It's ssems unnecessary or can you give a example about it

• You can also include a check in the tests about this case to avoid regressions after the line https://github.com/OCA/account-invoicing/blob/14.0/stock_picking_invoicing/tests/test_picking_invoicing.py#L858

   self.assertEqual(
        invoice_devolution.reversed_entry_id, invoice
   )
  

[mbcosta]

@DiegoParadeda just a example about the suggested changes, this seems work as expect but let me know if there something about the problem that I didn't see or understand

--- a/stock_picking_invoicing/wizards/stock_invoice_onshipping.py
+++ b/stock_picking_invoicing/wizards/stock_invoice_onshipping.py
@@ -316,6 +316,13 @@ class StockInvoiceOnshipping(models.TransientModel):
                 picking.picking_type_id,
                 picking.partner_id,
             )
+            # Refund Case should not be Group
+            refund_picking = picking.mapped(
+                "move_lines.origin_returned_move_id.picking_id"
+            )
+            if refund_picking:
+                key = key + (refund_picking,)
+        print('=========== KEY =====', key)
         return key


     def _group_pickings(self, pickings):
@@ -383,6 +390,17 @@ class StockInvoiceOnshipping(models.TransientModel):
                 "picking_ids": [(4, p.id, False) for p in pickings],
             }
         )
+        refund_picking = picking.mapped(
+                "move_lines.origin_returned_move_id.picking_id"
+        )
+        if refund_picking:
+            values["reversed_entry_id"] = refund_picking.mapped(
+                "invoice_ids"
+            )[0].id
+        print('======== Build Values Refund Picking ===',
+              values.get('reversed_entry_id')
+        )
+
 
         invoice, values = self._simulate_invoice_onchange(values)


--- a/stock_picking_invoicing/tests/test_picking_invoicing.py
+++ b/stock_picking_invoicing/tests/test_picking_invoicing.py
@@ -856,6 +856,13 @@ class TestPickingInvoicing(SavepointCase):
         wizard.action_generate()
         domain = [("picking_ids", "=", picking_devolution.id)]
         invoice_devolution = self.invoice_model.search(domain)
+        print('========= Invoice Devolution ===',
+              invoice,
+              invoice_devolution.reversed_entry_id
+        )
+        self.assertEqual(
+            invoice_devolution.reversed_entry_id, invoice
+        )
         # Confirm Return Invoice