Restore Thrift result-handler compatibility hooks

Keep existing e2e-only inspection hooks available through the facade while the new backend abstraction owns result handling.

Signed-off-by: Madhavendra Rathore <madhavendra.rathore@databricks.com>

Author: msrathore-db

lib/DBSQLOperation.ts

@@ -55,6 +55,8 @@ export default class DBSQLOperation implements IOperation {
 
   private cancelled: boolean = false;
 
+  public readonly _data?: unknown;
+
   private metadata?: ResultMetadata;
 
   private startTime: number = Date.now();
@@ -66,6 +68,7 @@ export default class DBSQLOperation implements IOperation {
   constructor(options: DBSQLOperationConstructorOptions) {
     this.context = options.context;
     this.backend = options.backend;
+    this._data = options.backend.dataProvider;
     this.sessionId = options.sessionId;
     this.context.getLogger().log(LogLevel.debug, `Operation created with id: ${this.id}`);
 

lib/contracts/IOperationBackend.ts

@@ -36,6 +36,12 @@ export default interface IOperationBackend {
   /** Optional Thrift operation type used for statement telemetry classification. */
   readonly operationType?: TOperationType;
 
+  /**
+   * Optional raw data provider exposed only for legacy tests that inspect
+   * result-handler internals. Not part of the public operation contract.
+   */
+  readonly dataProvider?: unknown;
+
   /**
    * Whether this operation has a result set.
    *

lib/thrift-backend/ThriftOperationBackend.ts

@@ -121,6 +121,10 @@ export default class ThriftOperationBackend implements IOperationBackend {
     return this.operationHandle.operationType;
   }
 
+  public get dataProvider() {
+    return this._data;
+  }
+
   public hasResultSet(): boolean {
     return Boolean(this.operationHandle.hasResultSet);
   }