feat: undefined json keys as defaults w/ Prefer:undefined-keys

test/pgbench/1567/old.sql

@@ -0,0 +1,12 @@
+INSERT INTO "test"."complex_items"("arr_data", "field-with_sep", "id", "name")
+SELECT pgrst_body."arr_data", pgrst_body."field-with_sep", pgrst_body."id", pgrst_body."name"
+FROM (
+  SELECT '[{"id": 4, "name": "Vier"}, {"id": 5, "name": "Funf", "arr_data": null}, {"id": 6, "name": "Sechs", "arr_data": [1, 2, 3], "field-with_sep": 6}]'::jsonb as json_data
+) pgrst_payload,
+LATERAL (
+  SELECT CASE WHEN jsonb_typeof(pgrst_payload.json_data) = 'array' THEN pgrst_payload.json_data ELSE jsonb_build_array(pgrst_payload.json_data) END AS val
+) pgrst_uniform_json,
+LATERAL (
+  SELECT * FROM jsonb_to_recordset (pgrst_uniform_json.val) AS _ ("arr_data" integer[], "field-with_sep" integer, "id" bigint, "name" text)
+) pgrst_body
+RETURNING "test"."complex_items".*