[FIX] mrp: fix qty_available for kit with sub-kits

Backport of d02851d5

---

On this situation:
* P1 consumable product, kit, with components P2 and P3 in its BoM using
  1 of each
* P2 comsumable product, kit, with component P3 using 1 in the BoM
* P3 storable product, 10 units in stock

Before:
The qyt_available for P1 is 10. That's incorrect: to assemble one P1 we
need precisely two of P3s, one for P2 BoM then an extra for P1 BoM.

After:
The qyt_available for P1 is 5.

closes odoo/odoo#123244

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

addons/mrp/models/product.py

 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+import collections
 from datetime import timedelta
 import operator as py_operator
 from odoo import api, fields, models
@@ -125,21 +126,28 @@ class ProductProduct(models.Model):
         qties = self.env.context.get("mrp_compute_quantities", {})
         qties.update(res)
         for product in bom_kits:
-            boms, bom_sub_lines = bom_kits[product].explode(product, 1)
+            bom_sub_lines = bom_kits[product].explode(product, 1)[1]
+            # group lines by component
+            bom_sub_lines_grouped = collections.defaultdict(list)
+            for info in bom_sub_lines:
+                bom_sub_lines_grouped[info[0].product_id].append(info)
             ratios_virtual_available = []
             ratios_qty_available = []
             ratios_incoming_qty = []
             ratios_outgoing_qty = []
             ratios_free_qty = []
-            for bom_line, bom_line_data in bom_sub_lines:
-                component = bom_line.product_id.with_context(mrp_compute_quantities=qties)
-                if component.type != 'product' or float_is_zero(bom_line_data['qty'], precision_rounding=bom_line.product_uom_id.rounding):
-                    # As BoMs allow components with 0 qty, a.k.a. optionnal components, we simply skip those
-                    # to avoid a division by zero. The same logic is applied to non-storable products as those
-                    # products have 0 qty available.
-                    continue
-                uom_qty_per_kit = bom_line_data['qty'] / bom_line_data['original_qty']
-                qty_per_kit = bom_line.product_uom_id._compute_quantity(uom_qty_per_kit, bom_line.product_id.uom_id, round=False, raise_if_failure=False)
+
+            for component, bom_sub_lines in bom_sub_lines_grouped.items():
+                component = component.with_context(mrp_compute_quantities=qties)
+                qty_per_kit = 0
+                for bom_line, bom_line_data in bom_sub_lines:
+                    if component.type != 'product' or float_is_zero(bom_line_data['qty'], precision_rounding=bom_line.product_uom_id.rounding):
+                        # As BoMs allow components with 0 qty, a.k.a. optionnal components, we simply skip those
+                        # to avoid a division by zero. The same logic is applied to non-storable products as those
+                        # products have 0 qty available.
+                        continue
+                    uom_qty_per_kit = bom_line_data['qty'] / bom_line_data['original_qty']
+                    qty_per_kit += bom_line.product_uom_id._compute_quantity(uom_qty_per_kit, bom_line.product_id.uom_id, round=False, raise_if_failure=False)
                 if not qty_per_kit:
                     continue
                 rounding = component.uom_id.rounding

addons/mrp/tests/common.py

@@ -154,3 +154,32 @@ class TestMrpCommon(common2.TestStockCommon):
                 (0, 0, {'product_id': cls.product_4.id, 'product_qty': 8}),
                 (0, 0, {'product_id': cls.product_2.id, 'product_qty': 12})
             ]})
+
+    @classmethod
+    def make_prods(cls, n):
+        return [
+            cls.env["product.product"].create(
+                {"name": f"p{k + 1}", "type": "product"}
+            )
+            for k in range(n)
+        ]
+
+    @classmethod
+    def make_bom(cls, p, *cs):
+        return cls.env["mrp.bom"].create(
+            {
+                "product_tmpl_id": p.product_tmpl_id.id,
+                "product_id": p.id,
+                "product_qty": 1,
+                "type": "phantom",
+                "product_uom_id": cls.uom_unit.id,
+                "bom_line_ids": [
+                    (0, 0, {
+                        "product_id": c.id,
+                        "product_qty": 1,
+                        "product_uom_id": cls.uom_unit.id
+                    })
+                    for c in cs
+                ],
+            }
+        )

addons/mrp/tests/test_bom.py

@@ -895,3 +895,15 @@ class TestBoM(TestMrpCommon):
             line.product_uom_id = uom_unit
             line.product_qty = 5
         bom_finished = bom_finished.save()
+
+    def test_bom_kit_with_sub_kit(self):
+        p1, p2, p3, p4 = self.make_prods(4)
+        self.make_bom(p1, p2, p3)
+        self.make_bom(p2, p3, p4)
+
+        loc = self.env.ref("stock.stock_location_stock")
+        self.env["stock.quant"]._update_available_quantity(p3, loc, 10)
+        self.env["stock.quant"]._update_available_quantity(p4, loc, 10)
+        self.assertEqual(p1.qty_available, 5.0)
+        self.assertEqual(p2.qty_available, 10.0)
+        self.assertEqual(p3.qty_available, 10.0)