[FIX] - check date_start before onchange

contract/models/contract_line.py

@@ -82,6 +82,7 @@ class AccountAnalyticInvoiceLine(models.Model):
     def _compute_state(self):
         today = fields.Date.context_today(self)
         for rec in self:
+            if rec.date_start:
                 if rec.is_canceled:
                     rec.state = 'canceled'
                 elif today < rec.date_start:
@@ -202,6 +203,7 @@ class AccountAnalyticInvoiceLine(models.Model):
         """Date end should be auto-computed if a contract line is set to
         auto_renew"""
         for rec in self.filtered('is_auto_renew'):
+            if rec.date_start:
                 rec.date_end = (
                     self.date_start
                     + self.get_relative_delta(