fix(client): Throw WorkflowExecutionAlreadyStartedError on signalWithStart (#1199)

Author: satazor

packages/client/src/workflow-client.ts

@@ -700,7 +700,14 @@ export class WorkflowClient extends BaseClient {
     };
     try {
       return (await this.workflowService.signalWithStartWorkflowExecution(req)).runId;
-    } catch (err) {
+    } catch (err: any) {
+      if (err.code === grpcStatus.ALREADY_EXISTS) {
+        throw new WorkflowExecutionAlreadyStartedError(
+          'Workflow execution already started',
+          options.workflowId,
+          workflowType
+        );
+      }
       this.rethrowGrpcError(err, 'Failed to signalWithStart Workflow', { workflowId: options.workflowId });
     }
   }

packages/test/src/integration-tests.ts

@@ -30,6 +30,7 @@ import {
   TimeoutType,
   WorkflowExecution,
   WorkflowExecutionAlreadyStartedError,
+  WorkflowIdReusePolicy,
   WorkflowNotFoundError,
 } from '@temporalio/common';
 import { msToNumber, tsToMs } from '@temporalio/common/lib/time';
@@ -1138,6 +1139,28 @@ export function runIntegrationTests(codec?: PayloadCodec): void {
     }
   });
 
+  test('WorkflowClient.signalWithStart fails with WorkflowExecutionAlreadyStartedError', async (t) => {
+    const { client } = t.context;
+    const workflowId = uuid4();
+    await client.execute(workflows.sleeper, {
+      taskQueue: 'test',
+      workflowId,
+    });
+    await t.throwsAsync(
+      client.signalWithStart(workflows.sleeper, {
+        taskQueue: 'test',
+        workflowId,
+        signal: workflows.interruptSignal,
+        signalArgs: ['interrupted from signalWithStart'],
+        workflowIdReusePolicy: WorkflowIdReusePolicy.WORKFLOW_ID_REUSE_POLICY_REJECT_DUPLICATE,
+      }),
+      {
+        instanceOf: WorkflowExecutionAlreadyStartedError,
+        message: 'Workflow execution already started',
+      }
+    );
+  });
+
   test('Handle from WorkflowClient.start follows only own execution chain', async (t) => {
     const { client } = t.context;
     const workflowId = uuid4();