stripe: End legacy plan on end_date.

corporate/lib/stripe.py

@@ -1651,6 +1651,9 @@ class BillingSession(ABC):
         else:
             next_billing_cycle = start_of_next_billing_cycle(plan, last_renewal)
 
+        if plan.end_date is not None:
+            next_billing_cycle = min(next_billing_cycle, plan.end_date)
+
         return next_billing_cycle
 
     # event_time should roughly be timezone_now(). Not designed to handle
@@ -1666,6 +1669,15 @@ class BillingSession(ABC):
         if event_in_next_billing_cycle and last_ledger_entry is not None:
             licenses_at_next_renewal = last_ledger_entry.licenses_at_next_renewal
             assert licenses_at_next_renewal is not None
+
+            if (
+                plan.tier == CustomerPlan.TIER_SELF_HOSTED_LEGACY
+                and plan.end_date == next_billing_cycle
+                and plan.status == CustomerPlan.ACTIVE
+            ):
+                self.process_downgrade(plan, True)
+                return None, None
+
             if plan.status == CustomerPlan.ACTIVE:
                 return None, LicenseLedger.objects.create(
                     plan=plan,

corporate/tests/test_stripe.py

@@ -7341,3 +7341,30 @@ class TestRemoteServerBillingFlow(StripeTestCase, RemoteServerTestCase):
         # Verify Zulip team receives mail for the next cycle.
         invoice_plans_as_needed(add_months(self.next_month, 1))
         self.assert_length(outbox, messages_count + 1)
+
+    @responses.activate
+    @mock_stripe()
+    def test_legacy_plan_ends_on_plan_end_date(self, *mocks: Mock) -> None:
+        self.login("hamlet")
+
+        self.add_mock_response()
+        with time_machine.travel(self.now, tick=False):
+            send_server_data_to_push_bouncer(consider_usage_statistics=False)
+
+        plan_end_date = add_months(self.now, 3)
+        self.billing_session.migrate_customer_to_legacy_plan(self.now, plan_end_date)
+
+        # Legacy plan ends on plan end date.
+        customer = self.billing_session.get_customer()
+        assert customer is not None
+        plan = get_current_plan_by_customer(customer)
+        assert plan is not None
+        self.assertEqual(
+            self.remote_server.plan_type, RemoteZulipServer.PLAN_TYPE_SELF_MANAGED_LEGACY
+        )
+        self.billing_session.make_end_of_cycle_updates_if_needed(plan, plan_end_date)
+        plan.refresh_from_db()
+        self.remote_server.refresh_from_db()
+        self.assertEqual(self.remote_server.plan_type, RemoteZulipServer.PLAN_TYPE_SELF_MANAGED)
+        self.assertEqual(plan.next_invoice_date, None)
+        self.assertEqual(plan.status, CustomerPlan.ENDED)