Prevent already scheduled tasks from being added to opentasks list

azure/durable_functions/models/DurableOrchestrationContext.py

@@ -661,6 +661,9 @@ def history_to_string(event):
 
     def _add_to_open_tasks(self, task: TaskBase):
 
+        if task._is_scheduled:
+            return
+
         if isinstance(task, AtomicTask):
             if task.id is None:
                 task.id = self._sequence_number

tests/orchestrator/test_sequential_orchestrator.py

@@ -95,6 +95,25 @@ def generator_function_reducing_when_all(context):
     yield context.call_activity("Hello", "London")
     return ""
 
+
+def generator_function_reuse_task_in_whenany(context):
+    task1 = context.call_activity("Hello", "Tokyo")
+    task2 = context.call_activity("Hello", "Seattle")
+    pending_tasks = [task1, task2]
+
+    #  Yield until first task is completed
+    finished_task1 = yield context.task_any(pending_tasks)
+
+    #  Remove completed task from pending tasks
+    pending_tasks.remove(finished_task1)
+
+    task3 = context.call_activity("Hello", "London")
+    tasks = pending_tasks + [task3]
+
+    #  Yield remaining tasks
+    yield context.task_any(tasks)
+    return ""
+
 def generator_function_compound_tasks(context):
     yield context.call_activity("Hello", "Tokyo")
 
@@ -731,6 +750,31 @@ def test_reducing_when_any_pattern():
 
     assert_orchestration_state_equals(expected, result)
 
+def test_reducing_when_any_pattern():
+    """Tests that a user can call when_any on a progressively smaller list of already scheduled tasks"""
+    context_builder = ContextBuilder('generator_function_reuse_task_in_whenany', replay_schema=ReplaySchema.V2)
+    add_hello_completed_events(context_builder, 0, "\"Hello Tokyo!\"")
+    add_hello_completed_events(context_builder, 1, "\"Hello Seattle!\"")
+    add_hello_completed_events(context_builder, 2, "\"Hello London!\"")
+
+    result = get_orchestration_state_result(
+        context_builder, generator_function_reuse_task_in_whenany)
+
+    # this scenario is only supported for V2 replay
+    expected_state = base_expected_state("",replay_schema=ReplaySchema.V2)
+    expected_state._actions = [
+        [WhenAnyAction(
+            [CallActivityAction("Hello", "Seattle"), CallActivityAction("Hello", "Tokyo")]),
+            WhenAnyAction(
+                [CallActivityAction("Hello", "London")])
+        ]
+    ]
+
+    expected_state._is_done = True
+    expected = expected_state.to_json()
+
+    assert_orchestration_state_equals(expected, result)
+
 def test_compound_tasks_return_single_action_in_V2():
     """Tests that compound tasks, in the v2 replay schema, are represented as a single "deep" action"""
     context_builder = ContextBuilder('test_v2_replay_schema', replay_schema=ReplaySchema.V2)