[FIX] stock_account: valuation change has always positive value

Steps to reproduce:
1. Create a new product with a cost of 10 (std, manual)
2. Create an inventory adjustment to set the quantity to -3
3. Change the product's category to real-time

Now the valuation for this product is -30€ but the accounting part
has 30€, creating a difference of 60€.

Before this commit:
Changing the valuation to real-time while having a negative
quantity/value gives a positive value in accounting.

After this commit:
Changing the valuation to real-time while having a negative
quantity/value gives a negative value in accounting.

opw-3390692

closes odoo/odoo#143000

X-original-commit: 9a0e620d2fa1d5e55d73bc4920f26ef2ba82ce9d
Signed-off-by: Arnold Moyaux (arm) <arm@odoo.com>
Signed-off-by: Walravens Mathieu (wama) <wama@odoo.com>

addons/stock_account/models/product.py

@@ -648,6 +648,11 @@ class ProductProduct(models.Model):
             debit_account_id = product_accounts[product.id]['stock_valuation'].id
             credit_account_id = product_accounts[product.id]['stock_input'].id
             value = out_stock_valuation_layer.value
+            if out_stock_valuation_layer.currency_id.compare_amounts(value, 0) < 0:
+                # Swap accounts makes a negative value in accounting
+                debit_account_id = product_accounts[product.id]['stock_output'].id
+                credit_account_id = product_accounts[product.id]['stock_valuation'].id
+
             move_vals = {
                 'journal_id': product_accounts[product.id]['stock_journal'].id,
                 'company_id': self.env.company.id,

addons/stock_account/tests/test_stockvaluationlayer.py

@@ -939,6 +939,12 @@ class TestStockValuationChangeValuation(TestStockValuationCommon):
             'property_stock_journal': cls.stock_journal.id,
         })
 
+    def _get_stock_account_balance(self, stock_valuation_layer):
+        """Return the accounting balance from the stock valuation account for the given SVL"""
+        stock_valuation_account = stock_valuation_layer.product_id.categ_id.property_stock_valuation_account_id
+        return stock_valuation_layer.account_move_id.line_ids.filtered(lambda line: line.account_id == stock_valuation_account).balance
+
+
     def test_standard_manual_to_auto_1(self):
         self.product1.product_tmpl_id.categ_id.property_cost_method = 'standard'
         self.product1.product_tmpl_id.categ_id.property_valuation = 'manual_periodic'
@@ -962,6 +968,9 @@ class TestStockValuationChangeValuation(TestStockValuationCommon):
         # An accounting entry should only be created for the replenish now that the category is perpetual.
         self.assertEqual(len(self.product1.stock_valuation_layer_ids.mapped('account_move_id')), 1)
         self.assertEqual(len(self.product1.stock_valuation_layer_ids), 3)
+        # Check the entry's value
+        last_svl = self.product1.stock_valuation_layer_ids.sorted()[-1]
+        self.assertEqual(self._get_stock_account_balance(last_svl), self.product1.value_svl)
         for svl in self.product1.stock_valuation_layer_ids.sorted()[-2:]:
             self.assertEqual(svl.description, 'Valuation method change for product category All: from manual_periodic to real_time.')
 
@@ -996,6 +1005,33 @@ class TestStockValuationChangeValuation(TestStockValuationCommon):
         # An accounting entry should only be created for the replenish now that the category is perpetual.
         self.assertEqual(len(self.product1.stock_valuation_layer_ids.mapped('account_move_id')), 1)
         self.assertEqual(len(self.product1.stock_valuation_layer_ids), 3)
+        # Check the entry's value
+        last_svl = self.product1.stock_valuation_layer_ids.sorted()[-1]
+        self.assertEqual(self._get_stock_account_balance(last_svl), self.product1.value_svl)
+
+    def test_standard_manual_to_auto_3(self):
+        self.product1.product_tmpl_id.categ_id.property_cost_method = 'standard'
+        self.product1.product_tmpl_id.categ_id.property_valuation = 'manual_periodic'
+        self.product1.product_tmpl_id.standard_price = 10
+        self._make_out_move(self.product1, 10, force_assign=True)
+
+        self.assertEqual(self.product1.value_svl, -100)
+        self.assertEqual(self.product1.quantity_svl, -10)
+        self.assertEqual(len(self.product1.stock_valuation_layer_ids.account_move_id), 0)
+        self.assertEqual(len(self.product1.stock_valuation_layer_ids), 1)
+
+        self.product1.product_tmpl_id.categ_id.property_valuation = 'real_time'
+
+        self.assertEqual(self.product1.value_svl, -100)
+        self.assertEqual(self.product1.quantity_svl, -10)
+        # An accounting entry should only be created for the replenish now that the category is perpetual.
+        self.assertEqual(len(self.product1.stock_valuation_layer_ids.account_move_id), 1)
+        self.assertEqual(len(self.product1.stock_valuation_layer_ids), 3)
+        # Check the entry's value
+        last_svl = self.product1.stock_valuation_layer_ids.sorted()[-1]
+        self.assertEqual(self._get_stock_account_balance(last_svl), self.product1.value_svl)
+        for svl in self.product1.stock_valuation_layer_ids.sorted()[-2:]:
+            self.assertEqual(svl.description, 'Valuation method change for product category All: from manual_periodic to real_time.')
 
     def test_standard_auto_to_manual_1(self):
         self.product1.product_tmpl_id.categ_id.property_cost_method = 'standard'