[FIX] mrp_multi_level: fix kit/phantom planning

fixes #1362

Ignoring qty_available for phantom products prevents double counting the
qty_available of components.

Creating planned orders for phantom products is simpler than recursively
exploding phantom BOMs. This also makes it easier to analyze the planning data
generated by the MRP calculation.

mrp_multi_level/models/mrp_inventory.py

@@ -89,8 +89,11 @@ class MrpInventory(models.Model):
     @api.depends("planned_order_ids", "planned_order_ids.qty_released")
     def _compute_to_procure(self):
         for rec in self:
-            rec.to_procure = sum(rec.planned_order_ids.mapped("mrp_qty")) - sum(
-                rec.planned_order_ids.mapped("qty_released")
+            rec.to_procure = (
+                0.0
+                if rec.supply_method == "phantom"
+                else sum(rec.planned_order_ids.mapped("mrp_qty"))
+                - sum(rec.planned_order_ids.mapped("qty_released"))
             )
 
     @api.depends(

mrp_multi_level/models/mrp_planned_order.py

@@ -59,6 +59,7 @@ class MrpPlannedOrder(models.Model):
     mrp_action = fields.Selection(
         selection=[
             ("manufacture", "Manufacturing Order"),
+            ("phantom", "Kit"),
             ("buy", "Purchase Order"),
             ("pull", "Pull From"),
             ("push", "Push To"),

mrp_multi_level/models/product_mrp_area.py

@@ -300,7 +300,3 @@ class ProductMRPArea(models.Model):
     def _get_locations(self):
         self.ensure_one()
         return self.mrp_area_id._get_locations()
-
-    def _should_create_planned_order(self):
-        self.ensure_one()
-        return not self.supply_method == "phantom"