[FIX] l10n_nl_tax_statement: don't break when writing list of ids

on x2many

l10n_nl_tax_statement/models/account_move_line.py

@@ -37,7 +37,9 @@ def check_field_is_equal(self, changed_protected_field, values):
         old_value = self[changed_protected_field]
         new_value = values[changed_protected_field]
         if field.type in ["many2many", "one2many"]:
-            # if field is X2M , the only acceptable value is
+            if all(isinstance(_id, int) for _id in new_value):
+                return new_value == old_value.ids
+            # if field is X2M , the only other acceptable value is
             # [[6,0,self[changed_protected_field].ids]]
             # wich is what the web client posts in case there is a editable X2M in form
             # that is unchanged.

l10n_nl_tax_statement/tests/test_l10n_nl_vat_statement.py

@@ -581,3 +581,8 @@ def test_20_multicompany(self):
 
         company_ids_full_list = statement_parent._get_company_ids_full_list()
         self.assertEqual(len(company_ids_full_list), 3)
+
+    def test_21_write_id_list(self):
+        self._create_test_invoice()
+        self.invoice_1.line_ids.write({"tax_tag_ids": self.tag_1.ids})
+        self.assertEqual(self.invoice_1.mapped("line_ids.tax_tag_ids"), self.tag_1)