Add default_pickle_library_override delegation to InteractiveRunner (#37752)

* Add default_pickle_library_override delegation to InteractiveRunner

* pylint

Author: praneetnadella

sdks/python/apache_beam/runners/interactive/interactive_runner.py

@@ -93,6 +93,12 @@ def is_fnapi_compatible(self):
     # return self._underlying_runner.is_fnapi_compatible()
     return False
 
+  def default_pickle_library_override(self):
+    """Delegates pickler override to the underlying runner."""
+    if hasattr(self._underlying_runner, 'default_pickle_library_override'):
+      return self._underlying_runner.default_pickle_library_override()
+    return super().default_pickle_library_override()
+
   def set_render_option(self, render_option):
     """Sets the rendering option.
 

sdks/python/apache_beam/runners/interactive/interactive_runner_test.py

@@ -43,6 +43,7 @@
 from apache_beam.runners.interactive.dataproc.types import ClusterMetadata
 from apache_beam.runners.interactive.testing.mock_env import isolated_env
 from apache_beam.runners.portability.flink_runner import FlinkRunner
+from apache_beam.runners.runner import PipelineRunner
 from apache_beam.testing.test_stream import TestStream
 from apache_beam.transforms.window import GlobalWindow
 from apache_beam.transforms.window import IntervalWindow
@@ -532,6 +533,25 @@ def test_defaults_to_efficient_cache(self):
     # Despite (highly redundant) windowing information, the cache is small.
     self.assertLess(size, sum(inputs))
 
+  def test_default_pickle_library_override_delegates(self):
+    mock_underlying = unittest.mock.MagicMock(spec=PipelineRunner)
+    mock_underlying.default_pickle_library_override.return_value = 'cloudpickle'
+
+    runner = interactive_runner.InteractiveRunner(
+        underlying_runner=mock_underlying)
+
+    self.assertEqual(runner.default_pickle_library_override(), 'cloudpickle')
+
+  def test_default_pickle_library_override_fallback(self):
+    mock_underlying = unittest.mock.MagicMock(spec=PipelineRunner)
+    del mock_underlying.default_pickle_library_override
+
+    runner = interactive_runner.InteractiveRunner(
+        underlying_runner=mock_underlying)
+
+    # Should fallback to the base class implementation without crashing
+    self.assertIsNone(runner.default_pickle_library_override())
+
 
 @unittest.skipIf(
     not ie.current_env().is_interactive_ready,