Fix <= .to3 migrations causing .to7 gendata migration failure

src/ert/storage/migration/to7.py

@@ -98,9 +98,7 @@ def _migrate_response_datasets(path: Path) -> None:
             responses_obj is not None
         ), f"Failed to load responses.json @ {responses_file}"
 
-        gendata_keys = {
-            k for k, v in responses_obj.items() if v["_ert_kind"] == "GenDataConfig"
-        }
+        gendata_keys = responses_obj.get("gen_data", {}).get("keys", [])
 
         for ens in ensembles:
             with open(ens / "index.json", encoding="utf-8") as f:
@@ -255,7 +253,7 @@ def _migrate_responses_from_netcdf_to_parquet(path: Path) -> None:
 
 
 def migrate(path: Path) -> None:
-    _migrate_response_datasets(path)
     _migrate_response_configs(path)
+    _migrate_response_datasets(path)
     _migrate_responses_from_netcdf_to_parquet(path)
     _migrate_observations_to_grouped_parquet(path)

tests/ert/unit_tests/storage/snapshots/test_storage_migration/test_that_storage_matches/gen_data

@@ -0,0 +1,21 @@
+realization,response_key,report_step,index,values
+0,GEN,1,0,0.0
+0,GEN,1,1,0.1
+1,GEN,1,0,0.0
+1,GEN,1,1,0.1
+2,GEN,1,0,0.0
+2,GEN,1,1,0.1
+3,GEN,1,0,0.0
+3,GEN,1,1,0.1
+4,GEN,1,0,0.0
+4,GEN,1,1,0.1
+5,GEN,1,0,0.0
+5,GEN,1,1,0.1
+6,GEN,1,0,0.0
+6,GEN,1,1,0.1
+7,GEN,1,0,0.0
+7,GEN,1,1,0.1
+8,GEN,1,0,0.0
+8,GEN,1,1,0.1
+9,GEN,1,0,0.0
+9,GEN,1,1,0.1

tests/ert/unit_tests/storage/test_storage_migration.py

@@ -184,6 +184,17 @@ def test_that_storage_matches(
             "observations",
         )
 
+        gen_data = ensemble.load_responses(
+            "gen_data", tuple(range(ensemble.ensemble_size))
+        )
+        snapshot.assert_match(
+            gen_data.sort(["realization", "response_key", "report_step", "index"])
+            .to_pandas()
+            .set_index(["realization", "response_key", "report_step", "index"])
+            .to_csv(),
+            "gen_data",
+        )
+
         assert ensemble.get_summary_keyset() == ["FOPR"]