[FIX] mrp: incorrect computation of the on-hand qty of a kit

Steps to reproduce the bug:
- Create a storable product “P1” with BOM:
    - Type: Kit
    - Quantity: 3
    - Components:
        - product “C1”, QTY: 5

- Update the quantity of “C1” to have 10 in stock
- Go to “P1” product form

Problem:
- The on-hand quantity is 2 instead of 6 →
  10 (available qty of c1) / (5 / 3) = 6

In the `_compute_quantities_dict` function, the `explode` function is
called to have the qty of the component necessary:
https://github.com/odoo/odoo/blob/ef4ae7f62d6b690b4745b4145ce25ff02b6b29f6/addons/mrp/models/product.py#L151
but it is the qty necessary for 3 kit according to what is indicated
in the BOM, so we will have 5 qty needed of “C1” as a result:
https://github.com/odoo/odoo/blob/49234be3418169c8f3c928493b86a1a67ab55914/addons/mrp/models/mrp_bom.py#L289
Then the quantity available in stock of the “C1” (10) is reduced by
the quantity needed (5), so 2:
https://github.com/odoo/odoo/blob/ef4ae7f62d6b690b4745b4145ce25ff02b6b29f6/addons/mrp/models/product.py#L188
But this result must be multiplied at
the end by the quantity set in the BOM (3), to get the quantity per kit
→ (10/5)* 3 = 6

opw-3010175

closes odoo/odoo#103584

X-original-commit: 8ede8a758a92c4b61fe48d820464783e21ee7847
Signed-off-by: William Henrotin (whe) <whe@odoo.com>
Signed-off-by: Djamel Touati (otd) <otd@odoo.com>

addons/mrp/models/product.py

@@ -240,11 +240,11 @@ class ProductProduct(models.Model):
                 ratios_free_qty.append(component_res["free_qty"] / qty_per_kit)
             if bom_sub_lines and ratios_virtual_available:  # Guard against all cnsumable bom: at least one ratio should be present.
                 res[product.id] = {
-                    'virtual_available': min(ratios_virtual_available) // 1,
-                    'qty_available': min(ratios_qty_available) // 1,
-                    'incoming_qty': min(ratios_incoming_qty) // 1,
-                    'outgoing_qty': min(ratios_outgoing_qty) // 1,
-                    'free_qty': min(ratios_free_qty) // 1,
+                    'virtual_available': min(ratios_virtual_available) * bom_kits[product].product_qty // 1,
+                    'qty_available': min(ratios_qty_available) * bom_kits[product].product_qty // 1,
+                    'incoming_qty': min(ratios_incoming_qty) * bom_kits[product].product_qty // 1,
+                    'outgoing_qty': min(ratios_outgoing_qty) * bom_kits[product].product_qty // 1,
+                    'free_qty': min(ratios_free_qty) * bom_kits[product].product_qty // 1,
                 }
             else:
                 res[product.id] = {

addons/mrp/tests/test_bom.py

@@ -366,7 +366,7 @@ class TestBoM(TestMrpCommon):
         # ending the recurse call to not call the compute method and just left the Falsy value `0.0`
         # for the components available qty.
         kit_product_qty, _, _ = (self.product_7_3 + self.product_2 + self.product_3).mapped("qty_available")
-        self.assertEqual(kit_product_qty, 2)
+        self.assertEqual(kit_product_qty, 8)
 
     def test_14_bom_kit_qty_multi_uom(self):
         uom_dozens = self.env.ref('uom.product_uom_dozen')