Ensure payload converters keep Uint8Array type equality (#1142) (#1143)

Closes #1142

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## What was changed
<!-- Describe what has changed in this PR -->

Modify BinaryPayloadConverter and ProtobufBinaryPayloadConverter so that
they wrap Uint8Array with an instance of Uint8Array from the workflow
context.

## Why?
<!-- Tell your future self why have you made these changes -->

Preserve instanceof semantics by payload converters

## Checklist
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1. Closes #1142 

3. How was this tested:
<!--- Please describe how you tested your changes/how we can test them
-->
Modified integration test args-and-return to check instanceof of an injected  Uint8Array

Author: antlai-temporal

packages/common/src/converter/payload-converter.ts

@@ -209,7 +209,12 @@ export class BinaryPayloadConverter implements PayloadConverterWithEncoding {
   }
 
   public fromPayload<T>(content: Payload): T {
-    return content.data as any;
+    return (
+      // Wrap with Uint8Array from this context to ensure `instanceof` works
+      (
+        content.data ? new Uint8Array(content.data.buffer, content.data.byteOffset, content.data.length) : content.data
+      ) as any
+    );
   }
 }
 

packages/common/src/converter/protobuf-payload-converters.ts

@@ -97,7 +97,9 @@ export class ProtobufBinaryPayloadConverter extends ProtobufPayloadConverter {
 
   public fromPayload<T>(content: Payload): T {
     const { messageType, data } = this.validatePayload(content);
-    return messageType.decode(data) as unknown as T;
+    // Wrap with Uint8Array from this context to ensure `instanceof` works
+    const localData = data ? new Uint8Array(data.buffer, data.byteOffset, data.length) : data;
+    return messageType.decode(localData) as unknown as T;
   }
 }
 

packages/test/src/workflows/args-and-return.ts

@@ -1,6 +1,10 @@
 import { decode } from '@temporalio/common/lib/encoding';
+import { ApplicationFailure } from '@temporalio/workflow';
 
-export async function argsAndReturn(greeting: string, _skip: undefined, arr: ArrayBuffer): Promise<string> {
-  const name = decode(new Uint8Array(arr));
+export async function argsAndReturn(greeting: string, _skip: undefined, arr: Uint8Array): Promise<string> {
+  if (!(arr instanceof Uint8Array)) {
+    throw ApplicationFailure.nonRetryable('Uint8Array not wrapped');
+  }
+  const name = decode(arr);
   return `${greeting}, ${name}`;
 }