fix(sdk): Resolves issue when using ParallelFor with param and depending tasks (#11903)

Signed-off-by: Mai Nakagawa <nakagawa.mai@gmail.com>

sdk/python/kfp/compiler/compiler_test.py

@@ -838,6 +838,23 @@ implementation:
                 with dsl.ParallelFor(items=single_param_task.output) as item:
                     print_and_return(text=item)
 
+    def test_compile_parallel_for_with_param_and_depending_task(self):
+
+        @dsl.component
+        def print_op(s: str):
+            print(s)
+
+        @dsl.pipeline
+        def my_pipeline(param: str):
+            with dsl.ParallelFor(items=['a', 'b']) as item:
+                parallel_tasks = print_op(s=item)
+            print_op(s=param).after(parallel_tasks)
+
+        with tempfile.TemporaryDirectory() as tempdir:
+            output_yaml = os.path.join(tempdir, 'result.yaml')
+            compiler.Compiler().compile(
+                pipeline_func=my_pipeline, package_path=output_yaml)
+
     def test_cannot_compile_parallel_for_with_single_artifact(self):
 
         with self.assertRaisesRegex(

sdk/python/kfp/compiler/compiler_utils.py

@@ -761,7 +761,9 @@ def get_dependencies(
                 # then make this validation dsl.Collected-aware
                 elif isinstance(upstream_parent_group, tasks_group.ParallelFor):
                     upstream_tasks_that_downstream_consumers_from = [
-                        channel.task.name for channel in task._channel_inputs
+                        channel.task.name
+                        for channel in task._channel_inputs
+                        if channel.task is not None
                     ]
                     has_data_exchange = upstream_task.name in upstream_tasks_that_downstream_consumers_from
                     # don't raise for .after