[FIX] stock: Fix forecast availability unit of measure mismatch

reserved_availability is expressed in move uom
forecast_availability must be in product base uom

closes odoo/odoo#75077

X-original-commit: fa9abcc1b105c07e1eaf6bdd3010abe19a056088
Signed-off-by: Rémy Voet <ryv-odoo@users.noreply.github.com>

addons/stock/models/stock_move.py

@@ -422,7 +422,8 @@ class StockMove(models.Model):
             if move.picking_type_id.code in self._consuming_picking_types() and is_unreserved:
                 outgoing_unreserved_moves_per_warehouse[warehouse_by_location[move.location_id]] |= move
             elif move.picking_type_id.code in self._consuming_picking_types():
-                move.forecast_availability = move.reserved_availability
+                move.forecast_availability = move.product_uom._compute_quantity(
+                    move.reserved_availability, move.product_id.uom_id, rounding_method='HALF-UP')
             elif move.picking_type_id.code == 'incoming':
                 move._get_forecast_availability_incoming()
 

addons/stock/tests/test_move.py

@@ -5409,3 +5409,37 @@ class StockMove(TransactionCase):
         warning = move._onchange_lot_ids()
         self.assertTrue(warning, 'Reuse of existing serial number (record) not detected')
         self.assertEqual(list(warning.keys())[0], 'warning', 'Warning message was not returned')
+
+    def test_forecast_availability(self):
+        """ Make an outgoing picking in dozens for a product stored in units.
+        Check that reserved_availabity is expressed in move uom and forecast_availability is in product base uom
+        """
+        # create product
+        product = self.env['product.product'].create({
+            'name': 'Product In Units',
+            'type': 'product',
+            'categ_id': self.env.ref('product.product_category_all').id,
+        })
+        # make some stock
+        self.env['stock.quant']._update_available_quantity(product, self.stock_location, 36.0)
+        # create picking
+        picking_out = self.env['stock.picking'].create({
+            'picking_type_id': self.env.ref('stock.picking_type_out').id,
+            'location_id': self.stock_location.id,
+            'location_dest_id': self.customer_location.id})
+        move = self.env['stock.move'].create({
+            'name': product.name,
+            'product_id': product.id,
+            'product_uom': self.uom_dozen.id,
+            'product_uom_qty': 2.0,
+            'picking_id': picking_out.id,
+            'location_id': self.stock_location.id,
+            'location_dest_id': self.customer_location.id})
+        # confirm
+        picking_out.action_confirm()
+        # check availability
+        picking_out.action_assign()
+        # check reserved_availabity expressed in move uom
+        self.assertEqual(move.reserved_availability, 2)
+        # check forecast_availability expressed in product base uom
+        self.assertEqual(move.forecast_availability, 24)