instaceof with Exceptions is broken.

[sobolk]

Checkboxes for prior research

• I've gone through Developer Guide and API reference
• I've checked AWS Forums and StackOverflow.
• I've searched for previous similar issues and didn't find any solution.

Describe the bug

We (AWS Amplify) got broken by smithy-lang/smithy-typescript#1484 .

This was dectected by our canary workflow here
https://github.com/aws-amplify/amplify-backend/actions/runs/12586737788/job/35081205621 .

Minimal repro:

import { NoSuchKey, S3, S3ServiceException } from '@aws-sdk/client-s3';

const dummyS3ServiceException = new S3ServiceException({
    name: 'TEST_ERROR',
    message: 'TEST_MESSAGE',
    $fault: 'server',
    $metadata: {},
});

console.log(dummyS3ServiceException instanceof NoSuchKey)

Prints

bcd0740fa72c:testapp073 sobkamil$ node index.js
true

The dummy S3ServiceException is not NoSuchKey error !!!

Regression Issue

• Select this option if this issue appears to be a regression.

SDK version number

"@aws-sdk/client-s3": "^3.721.0"

Which JavaScript Runtime is this issue in?

Node.js

Details of the browser/Node.js/ReactNative version

v20.18.1

Reproduction Steps

Minimal repro:

import { NoSuchKey, S3, S3ServiceException } from '@aws-sdk/client-s3';

const dummyS3ServiceException = new S3ServiceException({
    name: 'TEST_ERROR',
    message: 'TEST_MESSAGE',
    $fault: 'server',
    $metadata: {},
});

console.log(dummyS3ServiceException instanceof NoSuchKey)

Prints

bcd0740fa72c:testapp073 sobkamil$ node index.js
true

Observed Behavior

Exceptions are misscategorized with instaceof operator

Expected Behavior

console.log(dummyS3ServiceException instanceof NoSuchKey) returns false

Possible Solution

Revert smithy-lang/smithy-typescript#1484

Additional Information/Context

No response

[aBurmeseDev]

Hi @sobolk - it appears PR was merged and issue was resolved internally. Thanks again for reporting this. Closing now.