[FIX] partner_second_lastname: False value should be set on lastname2

not firstname

before this commit the following error happen:
name = 'Van-Eyck Jan'

this was converted to

firstname = False
lastname= 'Van-Eyck'
lastname2 = 'Jan'

and it should be like

firstname = 'Jan'
lastname= 'Van-Eyck'
lastname2 = False

partner_second_lastname/__manifest__.py

@@ -6,7 +6,7 @@
 {
     "name": "Partner second last name",
     "summary": "Have split first and second lastnames",
-    "version": "13.0.1.0.0",
+    "version": "13.0.2.0.0",
     "license": "AGPL-3",
     "website": "https://github.com/OCA/partner-contact",
     "author": "Tecnativa, " "Odoo Community Association (OCA)",

partner_second_lastname/models/res_partner.py

@@ -70,32 +70,46 @@ class ResPartner(models.Model):
         - If the partner is a company, save it in the lastname.
         - Otherwise, make a guess.
         """
-        # Company name goes to the lastname
         result = {
             "firstname": False,
             "lastname": name or False,
             "lastname2": False,
         }
-        if not is_company and name:
-            order = self._get_names_order()
-            result = super(ResPartner, self)._get_inverse_name(name, is_company)
-            parts = []
-            if order == "last_first":
-                if result["firstname"]:
-                    parts = result["firstname"].split(" ", 1)
-                while len(parts) < 2:
-                    parts.append(False)
-                result["lastname2"] = parts[0]
-                result["firstname"] = parts[1]
-            else:
-                if result["lastname"]:
-                    parts = result["lastname"].split(" ", 1)
-                while len(parts) < 2:
-                    parts.append(False)
-                result["lastname"] = parts[0]
-                result["lastname2"] = parts[1]
+
+        # Company name goes to the lastname
+        if not name or is_company:
+            return result
+
+        order = self._get_names_order()
+        result.update(super(ResPartner, self)._get_inverse_name(name, is_company))
+
+        if order in ("first_last", "last_first_comma"):
+            parts = self._split_part("lastname", result)
+            if parts:
+                result.update({"lastname": parts[0], "lastname2": u" ".join(parts[1:])})
+        else:
+            parts = self._split_part("firstname", result)
+            if parts:
+                result.update(
+                    {"firstname": parts[-1], "lastname2": u" ".join(parts[:-1])}
+                )
         return result
 
+    def _split_part(self, name_part, name_split):
+        """Split a given part of a name.
+
+        :param name_split: The parts of the name
+        :type dict
+
+        :param name_part: The part to split
+        :type str
+        """
+        name = name_split.get(name_part, False)
+        parts = name.split(" ", 1) if name else []
+        if not name or len(parts) < 2:
+            return False
+        return parts
+
     @api.constrains("firstname", "lastname", "lastname2")
     def _check_name(self):
         """Ensure at least one name is set."""

partner_second_lastname/tests/test_name.py

@@ -128,6 +128,15 @@ class PersonCase(TransactionCase):
             "name": "{} {}, {}".format(self.lastname, self.lastname2, self.firstname),
         }
 
+    def test_firstname_last_wo_comma(self):
+        """Create a person setting his first name last and the order as 'last_first'"""
+        self.env["ir.config_parameter"].set_param("partner_names_order", "last_first")
+        self.template = "%(last1)s %(last2)s %(first)s"
+        self.params = {
+            "is_company": False,
+            "name": "{} {} {}".format(self.lastname, self.lastname2, self.firstname),
+        }
+
     def test_firstname_only(self):
         """Create a person setting his first name only."""
         self.env["ir.config_parameter"].set_param("partner_names_order", "first_last")
@@ -157,6 +166,17 @@ class PersonCase(TransactionCase):
             "name": "{}, {}".format(self.lastname, self.firstname),
         }
 
+    def test_lastname_firstname_only_wo_comma(self):
+        """Create a person setting his last name 1 and first name only.
+        Set order to 'last_first' to test name split without comma"""
+        self.env["ir.config_parameter"].set_param("partner_names_order", "last_first")
+        self.lastname2 = False
+        self.template = "%(last1)s %(first)s"
+        self.params = {
+            "is_company": False,
+            "name": "{} {}".format(self.lastname, self.firstname),
+        }
+
     def test_separately(self):
         """Create a person setting separately all fields."""
         self.params = {