add stock_account_avco_negative_fix

stock_account_avco_negative_fix/README.md

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+# Stock Account AVCO Negative Fix
+
+Corrige un bug del core de Odoo 16 en la valoración de coste promedio (AVCO)
+que puede dejar el `standard_price` de un producto en un valor negativo (o
+cero) cuando existe stock negativo (`quantity_svl < 0`) y se recibe una
+compra que compensa solo parcialmente ese stock.
+
+## Descripción del problema
+
+El método `product_price_update_before_done()` de
+`stock_account/models/stock_move.py` calcula el nuevo coste medio ponderado
+de un producto AVCO con la fórmula:
+
+```
+new_std_price = (amount_unit * qty_svl + price_unit_in * qty) / (qty_svl + qty)
+```
+
+Cuando `(qty_svl + qty)` es un valor positivo muy pequeño (el stock negativo
+casi se compensa con la compra recibida, pero no del todo), el numerador
+puede resultar negativo y el `standard_price` calculado se vuelve negativo,
+corrompiendo la valoración de inventario en los recálculos posteriores.
+
+Bug reportado en upstream sin corrección oficial:
+https://github.com/odoo/odoo/issues/187169
+
+## Solución
+
+Este módulo **no** copia ni sobrescribe el algoritmo del core. En su lugar,
+hereda `stock.move` y aplica una estrategia de post-procesado con `super()`
+sobre `_action_done()`, basada en una **precondición** evaluada antes de que
+nada más intervenga:
+
+1. Antes de llamar a `super()`, para cada movimiento entrante AVCO relevante
+   (`move._is_in()` y `cost_method == 'average'`), comprueba si el producto
+   tenía `quantity_svl <= 0` **antes** de este movimiento (la precondición
+   bajo la cual el core puede degenerar a un coste negativo o cero). Si se
+   cumple, captura el `price_unit` entrante (`move._get_price_unit()`).
+2. Llama a `super()._action_done()` para que el core ejecute su lógica
+   completa sin modificaciones (media ponderada AVCO, rama FIFO y el
+   `_run_fifo_vacuum()` final).
+3. Después de `super()`, para cada producto marcado como "en riesgo" en el
+   paso 1, reescribe **incondicionalmente** su `standard_price` con el
+   `price_unit` capturado —sin comprobar el valor que haya quedado escrito—,
+   replicando el mismo patrón de escritura del core (`disable_auto_svl=True`,
+   `sudo()`) para no generar SVLs de revaluación espurios.
+
+**¿Por qué precondición incondicional y no comprobar el signo final?** Una
+primera versión de este fix comprobaba el signo de `standard_price`
+*después* de `super()`. Se detectó que ese criterio es insuficiente: otros
+módulos que reaccionan durante `_action_done()` (por ejemplo, el OCA
+`product_cost_price_avco_sync`, que sincroniza el coste AVCO al reaccionar a
+`stock.valuation.layer.write()` disparado por `_run_fifo_vacuum()`) pueden
+reescribir `standard_price` a un valor positivo pero distinto del esperado,
+haciendo que la comprobación `<= 0` nunca se cumpla aunque la situación de
+riesgo sí se haya dado. Al decidir **antes** de que empiece la cadena y
+aplicar la corrección de forma incondicional, el fix es robusto frente a
+cualquier módulo que reescriba `standard_price` durante el proceso, ahora o
+en el futuro.
+
+Este enfoque evita duplicar el algoritmo del core (resiliente a cambios de
+upstream) y es compatible con cualquier otro módulo, presente o futuro, que
+también herede `product_price_update_before_done`/`_action_done` sobre
+`stock.move`, ya que la cadena de `super()` se respeta íntegramente.
+
+## Alcance
+
+- Solo actúa sobre productos con `cost_method = 'average'`.
+- Productos FIFO o de coste estándar no se ven afectados.
+- No introduce modelos, vistas ni campos nuevos.
+
+## Créditos
+
+### Autores
+
+- Criptomart

stock_account_avco_negative_fix/__init__.py

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+from . import models

stock_account_avco_negative_fix/__manifest__.py

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+# Copyright 2026 Criptomart
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+{
+    "name": "Stock Account AVCO Negative Fix",
+    "version": "16.0.1.0.0",
+    "summary": "Prevent negative AVCO cost on incoming moves with negative stock",
+    "license": "AGPL-3",
+    "author": "Criptomart",
+    "website": "https://github.com/OCA/stock-logistics-workflow",
+    "depends": ["stock_account"],
+    "data": [],
+    "installable": True,
+}

stock_account_avco_negative_fix/models/__init__.py

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+from . import stock_move

stock_account_avco_negative_fix/models/stock_move.py

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+from odoo import models
+from odoo.tools import float_compare
+
+
+class StockMove(models.Model):
+    _inherit = "stock.move"
+
+    def _action_done(self, cancel_backorder=False):
+        """Fix negative AVCO ``standard_price`` after a move is done.
+
+        Odoo core (``stock_account/models/stock_move.py``,
+        ``product_price_update_before_done``) computes the new average cost
+        of an AVCO product as a weighted average between the current
+        valuation (``quantity_svl`` / ``standard_price``) and the incoming
+        move. When the product has non-positive stock (``quantity_svl <= 0``)
+        and the incoming quantity only partially compensates it, the
+        resulting weighted average can become negative or zero, corrupting
+        the product cost for every subsequent outgoing valuation.
+
+        This is a known, unfixed upstream bug: see
+        https://github.com/odoo/odoo/issues/187169
+
+        Rather than copying/overriding the core algorithm (which would break
+        compatibility with any OCA module -- present or future -- also
+        inheriting ``product_price_update_before_done``), we post-process the
+        final result of the whole ``_action_done`` flow:
+
+        - *Before* calling ``super()``, we detect the AVCO products that are
+          "at risk": incoming moves (``move._is_in()``) of a product with
+          ``cost_method == 'average'`` whose stock valuation quantity
+          (``quantity_svl``) is already ``<= 0`` *before* this move is
+          processed. This is exactly the precondition under which the core's
+          weighted-average formula can degenerate to a negative or zero
+          result. We capture, for each such ``(company, product)``, the
+          incoming move's own ``price_unit`` (``move._get_price_unit()``).
+        - We let ``super()._action_done()`` run its full logic unmodified
+          (AVCO weighted average, FIFO branch, and the ``_run_fifo_vacuum()``
+          step that runs at the very end of ``_action_done``).
+        - *After* ``super()`` has fully completed, for every "at risk"
+          ``(company, product)`` captured above, we unconditionally rewrite
+          ``standard_price`` with the captured incoming ``price_unit`` (not
+          the product's configured purchase price).
+
+        Note this fix is intentionally based on the *precondition*
+        (``quantity_svl <= 0`` before the move) rather than on inspecting the
+        *final* ``standard_price`` sign. An earlier version of this fix only
+        rewrote ``standard_price`` when it was left ``<= 0`` after
+        ``super()``, but that check could be silently bypassed: some module
+        reacting to the ``_run_fifo_vacuum()`` step (e.g. the OCA module
+        ``product_cost_price_avco_sync``, which hooks into
+        ``stock.valuation.layer.write()``) can rewrite ``standard_price`` to
+        a *different but still positive* value before our check ran,
+        preventing the fix from ever triggering even though the scenario
+        that causes the original bug did occur. Keying off the precondition
+        instead makes the fix robust regardless of what any other module
+        does afterwards, without depending on assumptions about whether the
+        vacuum runs in production (in practice, ``product_cost_price_avco_sync``
+        disables the vacuum outside of tests for performance reasons, since
+        it is only meaningful for FIFO -- but the fix should not rely on
+        that being permanently true).
+        """
+        at_risk_price_unit = {}
+        for move in self.filtered(
+            lambda m: m._is_in()
+            and m.with_company(m.company_id).product_id.cost_method == "average"
+        ):
+            company = move.company_id
+            product = move.product_id.with_company(company)
+            quantity_svl = product.sudo().quantity_svl
+            rounding = product.uom_id.rounding
+            if float_compare(quantity_svl, 0.0, precision_rounding=rounding) <= 0:
+                at_risk_price_unit[(company.id, product.id)] = move._get_price_unit()
+
+        res = super()._action_done(cancel_backorder=cancel_backorder)
+
+        if not at_risk_price_unit:
+            return res
+
+        companies = self.env["res.company"].browse(
+            {key[0] for key in at_risk_price_unit}
+        )
+        products = self.env["product.product"].browse(
+            {key[1] for key in at_risk_price_unit}
+        )
+        company_by_id = {company.id: company for company in companies}
+        product_by_id = {product.id: product for product in products}
+
+        for (company_id, product_id), price_unit in at_risk_price_unit.items():
+            company = company_by_id[company_id]
+            product = product_by_id[product_id]
+            product.with_company(company.id).with_context(
+                disable_auto_svl=True
+            ).sudo().write({"standard_price": price_unit})
+
+        return res

stock_account_avco_negative_fix/tests/__init__.py

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+from . import test_avco_negative_fix

stock_account_avco_negative_fix/tests/test_avco_negative_fix.py

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+from odoo.tests import tagged
+from odoo.tests.common import TransactionCase
+
+
+@tagged("post_install", "-at_install")
+class TestAvcoNegativeFix(TransactionCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.supplier_location = cls.env.ref("stock.stock_location_suppliers")
+        cls.customer_location = cls.env.ref("stock.stock_location_customers")
+        cls.stock_location = cls.env.ref("stock.stock_location_stock")
+        cls.picking_type_in = cls.env.ref("stock.picking_type_in")
+        cls.picking_type_out = cls.env.ref("stock.picking_type_out")
+        cls.categ_avco = cls.env["product.category"].create(
+            {"name": "Test AVCO category", "property_cost_method": "average"}
+        )
+        cls.categ_fifo = cls.env["product.category"].create(
+            {"name": "Test FIFO category", "property_cost_method": "fifo"}
+        )
+
+    def _create_product(self, categ, standard_price):
+        return self.env["product.product"].create(
+            {
+                "name": "Test product %s" % categ.name,
+                "type": "product",
+                "categ_id": categ.id,
+                "standard_price": standard_price,
+            }
+        )
+
+    def _validate_move(self, product, qty, location_id, location_dest_id, price_unit=None):
+        move_vals = {
+            "name": "test move",
+            "product_id": product.id,
+            "product_uom_qty": qty,
+            "product_uom": product.uom_id.id,
+            "location_id": location_id.id,
+            "location_dest_id": location_dest_id.id,
+        }
+        if price_unit is not None:
+            move_vals["price_unit"] = price_unit
+        move = self.env["stock.move"].create(move_vals)
+        move._action_confirm()
+        move.quantity_done = qty
+        move._action_done()
+        return move
+
+    def _sell_without_stock(self, product, qty):
+        return self._validate_move(
+            product, qty, self.stock_location, self.customer_location
+        )
+
+    def _receive(self, product, qty, price_unit):
+        return self._validate_move(
+            product, qty, self.supplier_location, self.stock_location, price_unit
+        )
+
+    def test_negative_result_is_corrected(self):
+        """TC-01 (RF-01): incoming move on a product with quantity_svl <= 0
+        (risk precondition) unconditionally gets standard_price set to the
+        incoming move's price unit, reproducing product_id=8611."""
+        product = self._create_product(self.categ_avco, 6.71)
+        self._sell_without_stock(product, 1.056)
+        self.assertAlmostEqual(product.quantity_svl, -1.056, places=3)
+        self.assertAlmostEqual(product.standard_price, 6.71, places=2)
+
+        self._receive(product, 1.0, 7.56)
+
+        self.assertGreater(product.standard_price, 0.0)
+        self.assertAlmostEqual(product.standard_price, 7.56, places=2)
+
+    def test_zero_result_is_corrected(self):
+        """TC-02 (RF-02): quantity_svl exactly 0 before the incoming move is
+        also a risk precondition; standard_price is set to the incoming
+        move's price unit."""
+        product = self._create_product(self.categ_avco, 6.0)
+        self._sell_without_stock(product, 2.0)
+        self.assertAlmostEqual(product.quantity_svl, -2.0, places=3)
+        self.assertAlmostEqual(product.standard_price, 6.0, places=2)
+
+        self._receive(product, 3.0, 4.0)
+
+        self.assertNotAlmostEqual(product.standard_price, 0.0, places=2)
+        self.assertAlmostEqual(product.standard_price, 4.0, places=2)
+
+    def test_positive_result_is_untouched(self):
+        """TC-03 (RF-03): with quantity_svl > 0 before the incoming move
+        (no risk precondition), the post-processing fix does not
+        intervene at all and the core's weighted average is left as-is."""
+        product = self._create_product(self.categ_avco, 1.0)
+        self._receive(product, 10.0, 10.0)
+        self.assertAlmostEqual(product.quantity_svl, 10.0, places=3)
+        self.assertAlmostEqual(product.standard_price, 10.0, places=2)
+
+        self._receive(product, 10.0, 20.0)
+
+        self.assertAlmostEqual(product.standard_price, 15.0, places=2)
+
+    def test_non_avco_product_not_affected(self):
+        """TC-04 (RF-04): the fix only applies to cost_method == 'average'
+        products; FIFO products follow the core's unmodified behaviour."""
+        product = self._create_product(self.categ_fifo, 5.0)
+        self.assertEqual(product.cost_method, "fifo")
+
+        self._receive(product, 10.0, 8.0)
+
+        self.assertAlmostEqual(product.standard_price, 8.0, places=2)