dont change __user / __cubejoinfield names in aliasing

Author: Nikita-str

packages/cubejs-schema-compiler/src/adapter/BaseQuery.js

@@ -3473,6 +3473,9 @@ export class BaseQuery {
     }
     // TODO: https://github.com/cube-js/cube.js/issues/4019
     // use single underscore for pre-aggregations to avoid fail of pre-aggregation name replace
+    if (name === '__user' || name === '__cubejoinfield') {
+      return name;
+    }
     return inflection.underscore(name).replace(/\./g, isPreAggregationName ? '_' : '__');
   }
 

rust/cubesql/cubesql/src/compile/test/test_wrapper.rs

@@ -925,9 +925,9 @@ async fn test_case_wrapper_with_system_fields() {
             .wrapped_sql
             .sql
             .contains(
-                "\\\"cubeName\\\":\\\"KibanaSampleDataEcommerce\\\",\\\"alias\\\":\\\"user\\\""
+                "\\\"cubeName\\\":\\\"KibanaSampleDataEcommerce\\\",\\\"alias\\\":\\\"__user\\\""
             ),
-        r#"SQL contains `\"cubeName\":\"KibanaSampleDataEcommerce\",\"alias\":\"user\"` {}"#,
+        r#"SQL contains `\"cubeName\":\"KibanaSampleDataEcommerce\",\"alias\":\"__user\"` {}"#,
         logical_plan.find_cube_scan_wrapped_sql().wrapped_sql.sql
     );