[FIX] mrp: done qty were missed to be taken into consideration

for qty changed finished product moves which would create negative moves
for closed production orders and therefore messing up forecasted quantities
without the possibility for a normal user to cleanup (delete or cancel)

closes odoo/odoo#86160

Signed-off-by: William Henrotin (whe) <whe@odoo.com>

addons/mrp/wizard/change_production_qty.py

@@ -36,9 +36,19 @@ class ChangeProductionQty(models.TransientModel):
         for move in production.move_finished_ids:
             if move.state in ('done', 'cancel'):
                 continue
-            qty = (new_qty - old_qty) * move.unit_factor
+            done_qty = sum(production.move_finished_ids.filtered(
+                lambda r:
+                    r.product_id == move.product_id and
+                    r.state == 'done'
+                ).mapped('product_uom_qty')
+            )
+            qty = (new_qty - old_qty) * move.unit_factor + done_qty
             modification[move] = (move.product_uom_qty + qty, move.product_uom_qty)
-            move.write({'product_uom_qty': move.product_uom_qty + qty})
+            if (move.product_uom_qty + qty) > 0:
+                move.write({'product_uom_qty': move.product_uom_qty + qty})
+            else:
+                move._action_cancel()
+
         return modification
 
     def change_prod_qty(self):