Correct the handling of UDT in CalciteScriptEngine by substituting calcite's type factory with OpenSearchTypeFactory

Signed-off-by: Yuanchun Shen <yuanchu@amazon.com>

Author: yuancu

opensearch/src/main/java/org/opensearch/sql/opensearch/storage/script/CalciteScriptEngine.java

@@ -79,6 +79,7 @@
 import org.opensearch.script.ScriptContext;
 import org.opensearch.script.ScriptEngine;
 import org.opensearch.search.lookup.SourceLookup;
+import org.opensearch.sql.calcite.utils.OpenSearchTypeFactory;
 import org.opensearch.sql.data.model.ExprTimestampValue;
 import org.opensearch.sql.data.type.ExprCoreType;
 import org.opensearch.sql.data.type.ExprType;
@@ -128,8 +129,7 @@ public <T> T compile(
     Map<String, ExprType> fieldTypes =
         (Map<String, ExprType>) objectMap.get(RelJsonSerializer.FIELD_TYPES);
 
-    JavaTypeFactoryImpl typeFactory =
-        new JavaTypeFactoryImpl(relJsonSerializer.getCluster().getTypeFactory().getTypeSystem());
+    JavaTypeFactory typeFactory = OpenSearchTypeFactory.TYPE_FACTORY;
     RexToLixTranslator.InputGetter getter = new ScriptInputGetter(typeFactory, rowType, fieldTypes);
     String code =
         CalciteScriptEngine.translate(

opensearch/src/main/java/org/opensearch/sql/opensearch/storage/serde/ExtendedRelJson.java

@@ -42,17 +42,6 @@ public static ExtendedRelJson create(JsonBuilder jsonBuilder) {
     return super.toJson(value);
   }
 
-  /**
-   * Jsonify an Object to string. When udtAsString is set, user-defined types are serialized to
-   * string types.
-   */
-  public @Nullable Object toJson(@Nullable Object value, boolean udtAsString) {
-    if (udtAsString) {
-      return super.toJson(value);
-    }
-    return toJson(value);
-  }
-
   private Object toJson(RelDataTypeField node) {
     final Map<String, @Nullable Object> map;
     if (node.getType().isStruct()) {

opensearch/src/main/java/org/opensearch/sql/opensearch/storage/serde/RelJsonSerializer.java

@@ -19,9 +19,7 @@
 import org.apache.calcite.plan.RelOptCluster;
 import org.apache.calcite.rel.externalize.RelJson;
 import org.apache.calcite.rel.type.RelDataType;
-import org.apache.calcite.rex.RexCall;
 import org.apache.calcite.rex.RexNode;
-import org.apache.calcite.sql.SqlBinaryOperator;
 import org.apache.calcite.sql.SqlOperatorTable;
 import org.apache.calcite.sql.fun.SqlLibrary;
 import org.apache.calcite.sql.fun.SqlLibraryOperatorTableFactory;
@@ -86,16 +84,7 @@ public String serialize(RexNode rexNode, RelDataType rowType, Map<String, ExprTy
       JsonBuilder jsonBuilder = new JsonBuilder();
       RelJson relJson = ExtendedRelJson.create(jsonBuilder);
       String rexNodeJson = jsonBuilder.toJsonString(relJson.toJson(rexNode));
-      Object rowTypeJsonObj;
-      // UDTs are not comparable when pushed-down as scripts. We set their types to strings as a
-      // workaround. Refer to this comment for more details:
-      // https://github.com/opensearch-project/sql/pull/4245#issuecomment-3268673999
-      if (rexNode instanceof RexCall
-          && ((RexCall) rexNode).getOperator() instanceof SqlBinaryOperator) {
-        rowTypeJsonObj = ((ExtendedRelJson) relJson).toJson(rowType, true);
-      } else {
-        rowTypeJsonObj = relJson.toJson(rowType);
-      }
+      Object rowTypeJsonObj = relJson.toJson(rowType);
       String rowTypeJson = jsonBuilder.toJsonString(rowTypeJsonObj);
       // Construct envelope of serializable objects
       Map<String, Object> envelope =