[FIX] sale: Fix fiscal pos. mapping taxes to price included

Using a fiscal position to map a tax to a price-included tax doesn't work.

closes odoo/odoo#70382

X-original-commit: 48ea669e0e6ff0ceb2f36828457e0d3773b38487
Signed-off-by: Antoine Vandevenne (anv) <AntoineVDV@users.noreply.github.com>
Signed-off-by: Laurent Smet <smetl@users.noreply.github.com>

3 files changed, 172 insertions, 3 deletions

diff --git a/addons/sale/models/sale.py b/addons/sale/models/sale.py
index 9c28c66a593..3cd616616b7 100644
--- a/addons/sale/models/sale.py
+++ b/addons/sale/models/sale.py
@@ -1648,6 +1648,43 @@ class SaleOrderLine(models.Model):
         # negative discounts (= surcharge) are included in the display price
         return max(base_price, final_price)
 
+    def _get_default_price_unit_from_product(self, product):
+        self.ensure_one()
+
+        currency = self.order_id.currency_id
+        fiscal_position = self.order_id.fiscal_position_id or self.order_id.partner_id.property_account_position_id
+        product_taxes = self.product_id.taxes_id.filtered(lambda r: r.company_id == self.order_id.company_id)
+        product_taxes_after_fp = fiscal_position.map_tax(product_taxes, partner=self.order_id.partner_id)
+        price_unit = self._get_display_price(product)
+
+        if set(product_taxes.ids) != set(product_taxes_after_fp.ids):
+            flattened_taxes = product_taxes._origin.flatten_taxes_hierarchy()
+            if any(tax.price_include for tax in flattened_taxes):
+                taxes_res = flattened_taxes.compute_all(
+                    price_unit,
+                    quantity=self.product_uom_qty,
+                    currency=currency,
+                    product=self.product_id,
+                    partner=self.order_id.partner_id,
+                )
+                price_unit = currency.round(taxes_res['total_excluded'])
+
+            flattened_taxes = product_taxes_after_fp._origin.flatten_taxes_hierarchy()
+            if any(tax.price_include for tax in flattened_taxes):
+                taxes_res = flattened_taxes.compute_all(
+                    price_unit,
+                    quantity=self.product_uom_qty,
+                    currency=currency,
+                    product=self.product_id,
+                    partner=self.order_id.partner_id,
+                    handle_price_include=False,
+                )
+                for tax_res in taxes_res['taxes']:
+                    tax = self.env['account.tax'].browse(tax_res['id'])
+                    if tax.price_include:
+                        price_unit += tax_res['amount']
+        return price_unit
+
     @api.onchange('product_id')
     def product_id_change(self):
         if not self.product_id:
@@ -1676,13 +1713,13 @@ class SaleOrderLine(models.Model):
             pricelist=self.order_id.pricelist_id.id,
             uom=self.product_uom.id
         )
-
         vals.update(name=self.get_sale_order_line_multiline_description_sale(product))
 
         self._compute_tax_id()
 
         if self.order_id.pricelist_id and self.order_id.partner_id:
-            vals['price_unit'] = self.env['account.tax']._fix_tax_included_price_company(self._get_display_price(product), product.taxes_id, self.tax_id, self.company_id)
+            vals['price_unit'] = self._get_default_price_unit_from_product(product)
+
         self.update(vals)
 
         title = False
@@ -1715,7 +1752,7 @@ class SaleOrderLine(models.Model):
                 uom=self.product_uom.id,
                 fiscal_position=self.env.context.get('fiscal_position')
             )
-            self.price_unit = self.env['account.tax']._fix_tax_included_price_company(self._get_display_price(product), product.taxes_id, self.tax_id, self.company_id)
+            self.price_unit = self._get_default_price_unit_from_product(product)
 
     def name_get(self):
         result = []
diff --git a/addons/sale/tests/__init__.py b/addons/sale/tests/__init__.py
index 88bf481bf04..b6629c7082a 100644
--- a/addons/sale/tests/__init__.py
+++ b/addons/sale/tests/__init__.py
@@ -12,3 +12,4 @@ from . import test_sale_refund
 from . import test_sale_signature
 from . import test_sale_transaction
 from . import test_sale_flow
+from . import test_sale_fiscal_position
diff --git a/addons/sale/tests/test_sale_fiscal_position.py b/addons/sale/tests/test_sale_fiscal_position.py
new file mode 100644
index 00000000000..2bc1e8c5126
--- /dev/null
+++ b/addons/sale/tests/test_sale_fiscal_position.py
@@ -0,0 +1,131 @@
+# -*- coding: utf-8 -*-
+from odoo import fields
+from odoo.addons.account.tests.common import AccountTestInvoicingCommon
+from odoo.tests import tagged
+from odoo.tests.common import Form
+
+
+@tagged('post_install', '-at_install')
+class TestSaleFiscalPosition(AccountTestInvoicingCommon):
+
+    def test_fiscal_pos_taxes_mapping_price_included_to_price_excluded(self):
+        ''' Test mapping a price-included tax (10%) with a price-excluded tax (20%) on a price_unit of 110.0.
+        The price_unit should be 100.0 after applying the fiscal position.
+        '''
+        tax_price_include = self.env['account.tax'].create({
+            'name': '10% incl',
+            'type_tax_use': 'sale',
+            'amount_type': 'percent',
+            'amount': 10,
+            'price_include': True,
+            'include_base_amount': True,
+        })
+        tax_price_exclude = self.env['account.tax'].create({
+            'name': '15% excl',
+            'type_tax_use': 'sale',
+            'amount_type': 'percent',
+            'amount': 15,
+        })
+
+        fiscal_position = self.env['account.fiscal.position'].create({
+            'name': 'fiscal_pos_a',
+            'tax_ids': [
+                (0, None, {
+                    'tax_src_id': tax_price_include.id,
+                    'tax_dest_id': tax_price_exclude.id,
+                }),
+            ],
+        })
+
+        product = self.env['product.product'].create({
+            'name': 'product',
+            'uom_id': self.env.ref('uom.product_uom_unit').id,
+            'lst_price': 110.0,
+            'taxes_id': [(6, 0, tax_price_include.ids)],
+        })
+
+        so_form = Form(self.env['sale.order'])
+        so_form.partner_id = self.partner_a
+        so_form.date_order = fields.Date.from_string('2019-01-01')
+        so_form.fiscal_position_id = fiscal_position
+        so_form.pricelist_id = self.env.ref('product.list0')
+        with so_form.order_line.new() as line:
+            line.product_id = product
+        so = so_form.save()
+
+        self.assertRecordValues(so.order_line, [{
+            'price_unit': 100.0,
+            'tax_id': tax_price_exclude.ids,
+        }])
+
+        uom_dozen = self.env.ref('uom.product_uom_dozen')
+        with Form(so) as so_form:
+            with so_form.order_line.edit(0) as line_form:
+                line_form.product_uom = uom_dozen
+
+        self.assertRecordValues(so.order_line, [{
+            'price_unit': 1200.0,
+            'tax_id': tax_price_exclude.ids,
+        }])
+
+    def test_fiscal_pos_taxes_mapping_price_included_to_price_included(self):
+        ''' Test mapping a price-included tax (10%) with another price-included tax (20%) on a price_unit of 110.0.
+        The price_unit should be 120.0 after applying the fiscal position.
+        '''
+        tax_price_include_1 = self.env['account.tax'].create({
+            'name': '10% incl',
+            'type_tax_use': 'sale',
+            'amount_type': 'percent',
+            'amount': 10,
+            'price_include': True,
+            'include_base_amount': True,
+        })
+        tax_price_include_2 = self.env['account.tax'].create({
+            'name': '20% incl',
+            'type_tax_use': 'sale',
+            'amount_type': 'percent',
+            'amount': 20,
+            'price_include': True,
+            'include_base_amount': True,
+        })
+
+        fiscal_position = self.env['account.fiscal.position'].create({
+            'name': 'fiscal_pos_a',
+            'tax_ids': [
+                (0, None, {
+                    'tax_src_id': tax_price_include_1.id,
+                    'tax_dest_id': tax_price_include_2.id,
+                }),
+            ],
+        })
+
+        product = self.env['product.product'].create({
+            'name': 'product',
+            'uom_id': self.env.ref('uom.product_uom_unit').id,
+            'lst_price': 110.0,
+            'taxes_id': [(6, 0, tax_price_include_1.ids)],
+        })
+
+        so_form = Form(self.env['sale.order'])
+        so_form.partner_id = self.partner_a
+        so_form.date_order = fields.Date.from_string('2019-01-01')
+        so_form.fiscal_position_id = fiscal_position
+        so_form.pricelist_id = self.env.ref('product.list0')
+        with so_form.order_line.new() as line:
+            line.product_id = product
+        so = so_form.save()
+
+        self.assertRecordValues(so.order_line, [{
+            'price_unit': 120.0,
+            'tax_id': tax_price_include_2.ids,
+        }])
+
+        uom_dozen = self.env.ref('uom.product_uom_dozen')
+        with Form(so) as so_form:
+            with so_form.order_line.edit(0) as line_form:
+                line_form.product_uom = uom_dozen
+
+        self.assertRecordValues(so.order_line, [{
+            'price_unit': 1440.0,
+            'tax_id': tax_price_include_2.ids,
+        }])