[FIX] account: get accounting date from invoicing date for vendor bills

In the first days of the month, many of the previous month's invoices
could still to be posted since the lock date is not yet set to the last
day of the previous month. To avoid the user having to modify the
default accounting date on each such bill, detect whether the conditions
allow the invoice to be posted on the very last day of the oldest
possible month, and then adapt the accounting date to the last day of
that month.

task-2575560

closes odoo/odoo#73701

X-original-commit: 2c5c1a4478505688f35e47ca20e7977b134d0fdb
Signed-off-by: Laurent Smet <smetl@users.noreply.github.com>
Signed-off-by: William André (wan) <wan@odoo.com>

addons/account/models/account_move.py

@@ -377,16 +377,50 @@ class AccountMove(models.Model):
     # ONCHANGE METHODS
     # -------------------------------------------------------------------------
 
-    @api.onchange('invoice_date')
+    def _get_accounting_date(self, invoice_date, has_tax):
+        """Get correct accounting date for previous periods, taking tax lock date into account.
+
+        When registering an invoice in the past, we still want the sequence to be increasing.
+        We then take the last day of the period, depending on the sequence format.
+        If there is a tax lock date and there are taxes involved, we register the invoice at the
+        last date of the first open period.
+
+        :param invoice_date (datetime.date): The invoice date
+        :param has_tax (bool): Iff any taxes are involved in the lines of the invoice
+        :return (datetime.date):
+        """
+        tax_lock_date = self.company_id.tax_lock_date
+        today = fields.Date.today()
+        if invoice_date and tax_lock_date and has_tax and invoice_date <= tax_lock_date:
+            invoice_date = tax_lock_date + timedelta(days=1)
+
+        if self.is_sale_document(include_receipts=True):
+            return max(invoice_date, today)
+        elif self.is_purchase_document(include_receipts=True):
+            highest_name = self.highest_name or self._get_last_sequence(relaxed=True)
+            number_reset = self._deduce_sequence_number_reset(highest_name)
+            if not highest_name or number_reset == 'month':
+                if (today.year, today.month) > (invoice_date.year, invoice_date.month):
+                    return date_utils.get_month(invoice_date)[1]
+                else:
+                    return max(invoice_date, today)
+            elif number_reset == 'year':
+                if today.year > invoice_date.year:
+                    return date(invoice_date.year, 12, 31)
+                else:
+                    return max(invoice_date, today)
+        return invoice_date
+
+    @api.onchange('invoice_date', 'highest_name', 'company_id')
     def _onchange_invoice_date(self):
         if self.invoice_date:
             if not self.invoice_payment_term_id and (not self.invoice_date_due or self.invoice_date_due < self.invoice_date):
                 self.invoice_date_due = self.invoice_date
-            if (
-                self.is_sale_document() and self.date != self.invoice_date
-                or self.is_purchase_document() and not self.date
-            ):
-                self.date = self.invoice_date
+
+            has_tax = bool(self.line_ids.tax_ids or self.line_ids.tax_tag_ids)
+            accounting_date = self._get_accounting_date(self.invoice_date, has_tax)
+            if accounting_date != self.date:
+                self.date = accounting_date
                 self._onchange_currency()
 
     @api.onchange('journal_id')
@@ -2555,7 +2589,7 @@ class AccountMove(models.Model):
             # /!\ 'check_move_validity' must be there since the dynamic lines will be recomputed outside the 'onchange'
             # environment.
             if (move.company_id.tax_lock_date and move.date <= move.company_id.tax_lock_date) and (move.line_ids.tax_ids or move.line_ids.tax_tag_ids):
-                move.date = fields.Date.context_today(self)
+                move.date = move._get_accounting_date(move.invoice_date or move.date, True)
                 move.with_context(check_move_validity=False)._onchange_currency()
 
         # Create the analytic lines in batch is faster as it leads to less cache invalidation.

addons/account/tests/test_account_move_in_invoice.py

@@ -138,6 +138,17 @@ class TestAccountMoveInInvoiceOnchanges(AccountTestInvoicingCommon):
             self.term_line_vals_1,
         ], self.move_vals)
 
+    def test_in_invoice_onchange_invoice_date(self):
+        for tax_date, invoice_date, accounting_date in [
+            ('2019-03-31', '2019-05-12', '2019-05-31'),
+            ('2019-03-31', '2019-02-10', '2019-04-30'),
+            ('2019-05-31', '2019-06-15', '2019-06-30'),
+        ]:
+            self.invoice.company_id.tax_lock_date = tax_date
+            with Form(self.invoice) as move_form:
+                move_form.invoice_date = invoice_date
+            self.assertEqual(self.invoice.date, fields.Date.to_date(accounting_date))
+
     def test_in_invoice_line_onchange_product_1(self):
         move_form = Form(self.invoice)
         with move_form.invoice_line_ids.edit(0) as line_form:

addons/account/tests/test_account_move_out_invoice.py

@@ -142,6 +142,18 @@ class TestAccountMoveOutInvoiceOnchanges(AccountTestInvoicingCommon):
             self.term_line_vals_1,
         ], self.move_vals)
 
+    @freeze_time('2020-01-15')
+    def test_out_invoice_onchange_invoice_date(self):
+        for tax_date, invoice_date, accounting_date in [
+            ('2019-03-31', '2019-05-12', '2020-01-15'),
+            ('2019-03-31', '2019-02-10', '2020-01-15'),
+            ('2019-05-31', '2019-06-15', '2020-01-15'),
+        ]:
+            self.invoice.company_id.tax_lock_date = tax_date
+            with Form(self.invoice) as move_form:
+                move_form.invoice_date = invoice_date
+            self.assertEqual(self.invoice.date, fields.Date.to_date(accounting_date))
+
     def test_out_invoice_line_onchange_product_1(self):
         move_form = Form(self.invoice)
         with move_form.invoice_line_ids.edit(0) as line_form:

addons/account/tests/test_payment_term.py

@@ -73,6 +73,7 @@ class TestAccountInvoiceRounding(AccountTestInvoicingCommon):
         with Form(self.invoice) as move_form:
             move_form.invoice_payment_term_id = pay_term
             move_form.invoice_date = invoice_date
+            move_form.date = invoice_date
         self.assertEqual(
             self.invoice.line_ids.filtered(
                 lambda l: l.account_id == self.company_data['default_account_receivable']