Don't fire on_reload when promoting to standby_leader on 13+ (#1552)

PostgreSQL 13 finally introduced the possibility to change the `primary_conninfo` without a restart. Just doing reload is enough, but in case if the role is changing from the `replica` to the `standby_leader` we want to call only `on_role_change` callback and skip `on_reload`, because they duplicate each other.

patroni/postgresql/__init__.py

@@ -615,9 +615,9 @@ class Postgresql(object):
         except psycopg2.Error:
             pass
 
-    def reload(self):
+    def reload(self, block_callbacks=False):
         ret = self.pg_ctl('reload')
-        if ret:
+        if ret and not block_callbacks:
             self.call_nowait(ACTION_ON_RELOAD)
         return ret
 
@@ -777,7 +777,8 @@ class Postgresql(object):
         if self.is_running():
             if do_reload:
                 self.config.write_postgresql_conf()
-                self.reload()
+                if self.reload(block_callbacks=change_role) and change_role:
+                    self.set_role(role)
             else:
                 self.restart(block_callbacks=change_role, role=role)
         else:

tests/test_ha.py

@@ -153,7 +153,6 @@ def run_async(self, func, args=()):
 @patch.object(Postgresql, 'is_leader', Mock(return_value=True))
 @patch.object(Postgresql, 'timeline_wal_position', Mock(return_value=(1, 10, 1)))
 @patch.object(Postgresql, '_cluster_info_state_get', Mock(return_value=3))
-@patch.object(Postgresql, 'call_nowait', Mock(return_value=True))
 @patch.object(Postgresql, 'data_directory_empty', Mock(return_value=False))
 @patch.object(Postgresql, 'controldata', Mock(return_value={
     'Database system identifier': SYSID,
@@ -705,6 +704,9 @@ class TestHa(PostgresInit):
         self.ha._leader_timeline = 1
         self.assertEqual(self.ha.run_cycle(), 'promoted self to a standby leader because i had the session lock')
         self.assertEqual(self.ha.run_cycle(), 'no action.  i am the standby leader with the lock')
+        self.p.set_role('replica')
+        self.p.config.check_recovery_conf = Mock(return_value=(True, False))
+        self.assertEqual(self.ha.run_cycle(), 'promoted self to a standby leader because i had the session lock')
 
     def test_process_healthy_standby_cluster_as_cascade_replica(self):
         self.p.is_leader = false