Fixing the failing test test_window on DB (#2484)

By making the 'outReference' be lazy. Because on Databricks, it
will get some invalid expressions in the 'projectList' if binding
the reference on driver side. E.g. 'none#0L', 'none@1L'.

Signed-off-by: Firestarman <firestarmanllc@gmail.com>

integration_tests/src/main/python/udf_cudf_test.py

@@ -14,7 +14,7 @@
 
 import pytest
 
-from conftest import is_at_least_precommit_run, is_databricks_runtime
+from conftest import is_at_least_precommit_run
 
 from pyspark.sql.pandas.utils import require_minimum_pyarrow_version, require_minimum_pandas_version
 try:
@@ -275,8 +275,6 @@ def gpu_run(spark):
 
 # ======= Test Window In Pandas =======
 @cudf_udf
-@pytest.mark.xfail(condition=is_databricks_runtime(),
-    reason='https://github.com/NVIDIA/spark-rapids/issues/2372')
 def test_window(enable_cudf_udf):
     @pandas_udf("int")
     def _sum_cpu_func(v: pd.Series) -> int:

shims/spark301db/src/main/scala/com/nvidia/spark/rapids/shims/spark301db/GpuWindowInPandasExec.scala

@@ -54,7 +54,7 @@ case class GpuWindowInPandasExec(
     }
   }
 
-  private val outReferences = {
+  private lazy val outReferences = {
     val allExpressions = windowFramesWithExpressions.map(_._2).flatten
     val references = allExpressions.zipWithIndex.map { case (e, i) =>
       // Results of window expressions will be on the right side of child's output

shims/spark310db/src/main/scala/org/apache/spark/sql/rapids/execution/python/shims/spark310db/GpuWindowInPandasExec.scala

@@ -64,7 +64,7 @@ case class GpuWindowInPandasExec(
     }
   }
 
-  private val outReferences = {
+  private lazy val outReferences = {
     val allExpressions = windowFramesWithExpressions.map(_._2).flatten
     val references = allExpressions.zipWithIndex.map { case (e, i) =>
       // Results of window expressions will be on the right side of child's output