fix return wizard "set qty to 0"

Add method to auto unpack on return

stock_usability/stock.py

@@ -170,6 +170,32 @@ class StockIncoterms(models.Model):
         return res
 
 
+class StockQuant(models.Model):
+    _inherit = 'stock.quant'
+
+    @api.model
+    def _cron_auto_unpack_on_internal_locations(self):
+        # Problem in v10: when you manage packs in Odoo for customer pickings,
+        # you have the following problem: when you return a customer picking,
+        # if you return all the products that were in the same pack, the pack
+        # is returned, so you have in your stock one or several quants
+        # inside a pack. This is a problem when you want to ship those
+        # products again.
+        # I provide the code in this module, but not the cron, because in some
+        # scenarios, you may want to have packs in your stock.
+        # Just add the cron in the specific module of your project.
+        # Underlying problem solved in Odoo v11. Don't port that to v14 !
+        logger.info('START cron auto unpack on internal locations')
+        int_locs = self.env['stock.location'].search([('usage', '=', 'internal')])
+        quants = self.search([
+            ('location_id', 'in', int_locs.ids),
+            ('package_id', '!=', False)])
+        packages = quants.mapped('package_id')
+        logger.info('Unpacking %d packages on internal locations', len(packages))
+        packages.unpack()
+        logger.info('END cron auto unpack on internal locations')
+
+
 class ProcurementGroup(models.Model):
     _inherit = 'procurement.group'
 

stock_usability/wizard/stock_picking_return.py

@@ -14,4 +14,5 @@ class StockReturnPicking(models.TransientModel):
         self.product_return_moves.write({'quantity': 0})
         action = self.env.ref('stock.act_stock_return_picking').read()[0]
         action['res_id'] = self.id
+        action['context'] = self._context
         return action