From 3808da237dae5bf316d8cd89c9f945e1b6777262 Mon Sep 17 00:00:00 2001
From: Dan Davison <dan.davison@temporal.io>
Date: Thu, 19 Dec 2024 09:40:40 -0500
Subject: [PATCH] Error on constructing start operation with invalid conflict
 policy

---
 temporalio/client.py                   |  2 ++
 tests/worker/test_update_with_start.py | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/temporalio/client.py b/temporalio/client.py
index 4b1c561d..52129e2c 100644
--- a/temporalio/client.py
+++ b/temporalio/client.py
@@ -2615,6 +2615,8 @@ def __init__(
         name, result_type_from_run_fn = (
             temporalio.workflow._Definition.get_name_and_result_type(workflow)
         )
+        if id_conflict_policy == temporalio.common.WorkflowIDConflictPolicy.UNSPECIFIED:
+            raise ValueError("WorkflowIDConflictPolicy is required")
 
         self._start_workflow_input = UpdateWithStartStartWorkflowInput(
             workflow=name,
diff --git a/tests/worker/test_update_with_start.py b/tests/worker/test_update_with_start.py
index 7c169352..160590e3 100644
--- a/tests/worker/test_update_with_start.py
+++ b/tests/worker/test_update_with_start.py
@@ -496,3 +496,22 @@ async def test_update_with_start_client_outbound_interceptor(
 
         wf_handle = await start_op.workflow_handle()
         assert await wf_handle.result() == "intercepted-workflow-arg"
+
+
+def test_with_start_workflow_operation_requires_conflict_policy():
+    with pytest.raises(ValueError):
+        WithStartWorkflowOperation(
+            WorkflowForUpdateWithStartTest.run,
+            0,
+            id="wid-1",
+            id_conflict_policy=WorkflowIDConflictPolicy.UNSPECIFIED,
+            task_queue="test-queue",
+        )
+
+    with pytest.raises(TypeError):
+        WithStartWorkflowOperation(  # type: ignore
+            WorkflowForUpdateWithStartTest.run,
+            0,
+            id="wid-1",
+            task_queue="test-queue",
+        )