Infer result type from result_type arg under string name overload

Author: dandavison

temporalio/client.py

@@ -446,7 +446,7 @@ async def start_workflow(
         args: Sequence[Any] = [],
         id: str,
         task_queue: str,
-        result_type: Optional[Type] = None,
+        result_type: Optional[Type[ReturnType]] = None,
         execution_timeout: Optional[timedelta] = None,
         run_timeout: Optional[timedelta] = None,
         task_timeout: Optional[timedelta] = None,
@@ -471,7 +471,7 @@ async def start_workflow(
         request_eager_start: bool = False,
         priority: temporalio.common.Priority = temporalio.common.Priority.default,
         versioning_override: Optional[temporalio.common.VersioningOverride] = None,
-    ) -> WorkflowHandle[Any, Any]: ...
+    ) -> WorkflowHandle[Any, ReturnType]: ...
 
     async def start_workflow(
         self,
@@ -727,7 +727,7 @@ async def execute_workflow(
         args: Sequence[Any] = [],
         id: str,
         task_queue: str,
-        result_type: Optional[Type] = None,
+        result_type: Optional[Type[ReturnType]] = None,
         execution_timeout: Optional[timedelta] = None,
         run_timeout: Optional[timedelta] = None,
         task_timeout: Optional[timedelta] = None,
@@ -752,7 +752,7 @@ async def execute_workflow(
         request_eager_start: bool = False,
         priority: temporalio.common.Priority = temporalio.common.Priority.default,
         versioning_override: Optional[temporalio.common.VersioningOverride] = None,
-    ) -> Any: ...
+    ) -> ReturnType: ...
 
     async def execute_workflow(
         self,
@@ -940,10 +940,10 @@ async def execute_update_with_start_workflow(
         start_workflow_operation: WithStartWorkflowOperation[Any, Any],
         args: Sequence[Any] = [],
         id: Optional[str] = None,
-        result_type: Optional[Type] = None,
+        result_type: Optional[Type[LocalReturnType]] = None,
         rpc_metadata: Mapping[str, str] = {},
         rpc_timeout: Optional[timedelta] = None,
-    ) -> Any: ...
+    ) -> LocalReturnType: ...
 
     async def execute_update_with_start_workflow(
         self,
@@ -1061,10 +1061,10 @@ async def start_update_with_start_workflow(
         wait_for_stage: WorkflowUpdateStage,
         args: Sequence[Any] = [],
         id: Optional[str] = None,
-        result_type: Optional[Type] = None,
+        result_type: Optional[Type[LocalReturnType]] = None,
         rpc_metadata: Mapping[str, str] = {},
         rpc_timeout: Optional[timedelta] = None,
-    ) -> WorkflowUpdateHandle[Any]: ...
+    ) -> WorkflowUpdateHandle[LocalReturnType]: ...
 
     async def start_update_with_start_workflow(
         self,

tests/worker/test_workflow.py

@@ -204,7 +204,7 @@ async def run(self, param1: int, param2: str) -> str:
 
 async def test_workflow_multi_param(client: Client):
     # This test is mostly just here to confirm MyPy type checks the multi-param
-    # overload approach properly
+    # overload approach  properly, and infers result type from result_type.
     async with new_worker(
         client, MultiParamWorkflow, activities=[multi_param_activity]
     ) as worker:
@@ -216,6 +216,15 @@ async def test_workflow_multi_param(client: Client):
         )
         assert result == "param1: 123, param2: val1"
 
+        result_via_name_overload = await client.execute_workflow(
+            "MultiParamWorkflow",
+            args=[123, "val1"],
+            id=f"workflow-{uuid.uuid4()}",
+            task_queue=worker.task_queue,
+            result_type=str,
+        )
+        assert result_via_name_overload == "param1: 123, param2: val1"
+
 
 @workflow.defn
 class InfoWorkflow: