fix: validate search alias checkpoints

backend/test_minjust_opensearch.py

@@ -24,6 +24,8 @@ class MinjustOpenSearchTest(unittest.TestCase):
 
         with self.assertRaisesRegex(ValueError, "differ"):
             switch_alias("http://127.0.0.1:9200", "same", "same")
+        with self.assertRaisesRegex(ValueError, "differ"):
+            switch_alias("http://127.0.0.1:9200", "index", "")
         with patch("search.minjust_opensearch.request_json", return_value={"acknowledged": False}):
             with self.assertRaisesRegex(RuntimeError, "did not acknowledge"):
                 switch_alias("http://127.0.0.1:9200", "index", "alias")
@@ -125,6 +127,30 @@ class MinjustOpenSearchTest(unittest.TestCase):
             self.assertEqual(state["last_document_code"], "7")
             self.assertTrue(state["complete"])
 
+            legacy = state.copy()
+            legacy.pop("alias")
+            legacy["schema_version"] = 1
+            legacy["last_document_code"] = "8"
+            legacy["complete"] = False
+            checkpoint.write_text(json.dumps(legacy), encoding="utf-8")
+            with patch("search.minjust_opensearch.request_json") as request:
+                request.side_effect = [
+                    {"cluster_uuid": "cluster-1"},
+                    {"test-index": {"settings": {"index": {"uuid": "index-1"}}}},
+                ]
+                self.assertEqual(
+                    load_bulk(
+                        root / "normalized",
+                        "http://127.0.0.1:9200",
+                        "test-index",
+                        maximum_bytes=4096,
+                        resume=True,
+                        checkpoint=checkpoint,
+                    ),
+                    (1, 0),
+                )
+            self.assertEqual(json.loads(checkpoint.read_text(encoding="utf-8"))["schema_version"], 2)
+
             state["last_document_code"] = "8"
             state["complete"] = False
             checkpoint.write_text(json.dumps(state), encoding="utf-8")