[FIX] account, account_asset, purchase: extra field in auto fill

The Purchase module provides a functionality to add pre-filled invoice
lines to an invoice. The issue is that extensions of the accounting
modules might add fields on an invoice line, and one would like to see
these fields populated as well.

This is the case for account_asset, which adds an asset_category_id on
an invoice line. However, the Purchase module is not aware of the fields
added by account_asset, and therefore it cannot populate them.

This fix adds a method, _auto_fill_extra, which is intended to manage
these extra fields.

opw-667162

addons/account/models/account_invoice.py

@@ -1185,6 +1185,16 @@ class AccountInvoiceLine(models.Model):
             result['warning'] = warning
         return result
 
+    def _set_additional_fields(self, invoice):
+        """ Some modules, such as Purchase, provide a feature to add automatically pre-filled
+            invoice lines. However, these modules might not be aware of extra fields which are
+            added by extensions of the accounting module.
+            This method is intended to be overridden by these extensions, so that any new field can
+            easily be auto-filled as well.
+            :param invoice : account.invoice corresponding record
+            :rtype line : account.invoice.line record
+        """
+        pass
 
 class AccountInvoiceTax(models.Model):
     _name = "account.invoice.tax"

addons/account_asset/account_asset_invoice.py

@@ -72,6 +72,12 @@ class AccountInvoiceLine(models.Model):
             elif self.invoice_id.type == 'in_invoice':
                 self.asset_category_id = self.product_id.product_tmpl_id.asset_category_id
 
+    def _set_additional_fields(self, invoice):
+        if invoice.type == 'out_invoice':
+            self.asset_category_id = self.product_id.product_tmpl_id.deferred_revenue_category_id.id
+        elif invoice.type == 'in_invoice':
+            self.asset_category_id = self.product_id.product_tmpl_id.asset_category_id.id
+        super(AccountInvoiceLine, self)._set_additional_fields(invoice)
 
 class ProductTemplate(models.Model):
     _inherit = 'product.template'

addons/purchase/invoice.py

@@ -68,6 +68,7 @@ class AccountInvoice(models.Model):
             if account:
                 data['account_id'] = account.id
             new_line = new_lines.new(data)
+            new_line._set_additional_fields(self)
             new_lines += new_line
 
         self.invoice_line_ids += new_lines