Fix upgrade changed event executing too early (#217)

Author: marceloneppel

src/upgrade.py

@@ -115,7 +115,7 @@ def _on_postgresql_pebble_ready(self, event: WorkloadEvent) -> None:
 
     def _on_upgrade_changed(self, _) -> None:
         """Update the Patroni nosync tag in the unit if needed."""
-        if not self.peer_relation:
+        if not self.peer_relation or not self.charm._patroni.member_started:
             return
 
         self.charm.update_config()

tests/unit/test_upgrade.py

@@ -149,9 +149,15 @@ def test_on_postgresql_pebble_ready(
         _set_unit_failed.assert_not_called()
 
     @patch("charm.PostgresqlOperatorCharm.update_config")
-    def test_on_upgrade_changed(self, _update_config):
+    @patch("charm.Patroni.member_started", new_callable=PropertyMock)
+    def test_on_upgrade_changed(self, _member_started, _update_config):
+        _member_started.return_value = False
         relation = self.harness.model.get_relation("upgrade")
         self.charm.on.upgrade_relation_changed.emit(relation)
+        _update_config.assert_not_called()
+
+        _member_started.return_value = True
+        self.charm.on.upgrade_relation_changed.emit(relation)
         _update_config.assert_called_once()
 
     @patch("charm.PostgreSQLUpgrade._set_rolling_update_partition")