exception is not of expected S3ServiceException type after @aws-sdk/client-s3 upgrade

[yoni-alaluf]

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

After we've upgraded minor @aws-sdk/client-s3 version from 3.930.0 -> 3.931.0
We started getting errors which related to the fact that our code is not handling correctly the errors from the sdk.
Till now on 304/404 error codes we have got an S3ServiceException instance where after the upgrade this is not the situation no more.
Example of our code till now that worked, and after the upgrade it no longer answer true on the - error instanceof S3ServiceException condition . the error does contain the correct status code error.$metadata?.httpStatusCode but this broke our code due to this behaviour.

function handleError(error: any, fileName: string, raiseErrorOnNotFound = true) {
  if (error instanceof S3ServiceException) {
    if (error.$metadata?.httpStatusCode === 304) {
      return { status: 'NOT_MODIFIED' };
    }
    if (error.$metadata?.httpStatusCode === 404) {
      if (raiseErrorOnNotFound) {
        throw error;
      }
      return { status: 'NOT_FOUND' };
    }
  }
  throw error;
}

Regression Issue

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

SDK version number

@aws-sdk/client-s3@3.931.0

Which JavaScript Runtime is this issue in?

Node.js

Details of the browser/Node.js/ReactNative version

v20.12.2

Reproduction Steps

• use @aws-sdk/client-s3@3.930.0
• download non exist file (same for 304 with sending existing ifNonMatch etag)
• status returned
• upgrade @aws-sdk/client-s3@3.931.0
• fetch the file - error is thrown

async function fetchFile(bucketName: string, filename:string, lastEtag: string){
  const downloadCommand = new GetObjectCommand({
    Bucket: bucketName,
    Key: filename,
    IfNoneMatch: lastEtag,
  });
  try{
    const downloadResponse = await s3Client.send(downloadCommand);
  } catch (error: any) {
    if (error instanceof S3ServiceException) {
      if (error.$metadata?.httpStatusCode === 304 || error.$metadata?.httpStatusCode === 404) {
        return 'as-expected';
      }
    }
    throw error;
  }
}

Observed Behavior

failed to fetch from S3 Error: Unknown
at ProtocolLib.getErrorSchemaOrThrowBaseException (/app/node_modules/@aws-sdk/core/dist-cjs/submodules/protocols/index.js:71:63)
at AwsRestXmlProtocol.handleError (/app/node_modules/@aws-sdk/core/dist-cjs/submodules/protocols/index.js:1610:65)
at AwsRestXmlProtocol.deserializeResponse (/app/node_modules/@aws-sdk/core/node_modules/@smithy/core/dist-cjs/submodules/protocols/index.js:301:24)
at processTicksAndRejections (node:internal/process/task_queues:95:5)
at /app/node_modules/@aws-sdk/client-s3/node_modules/@smithy/core/dist-cjs/submodules/schema/index.js:26:24
at /app/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:386:20
at /app/node_modules/@aws-sdk/client-s3/node_modules/@smithy/middleware-retry/dist-cjs/index.js:254:46
at /app/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:63:28
at /app/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:90:20
at /app/node_modules/@aws-sdk/client-s3/node_modules/@aws-sdk/middleware-logger/dist-cjs/index.js:5:26
...
...
  '$metadata': {
    httpStatusCode: 304,
      requestId: 'YMAGTEYBCZATMZAN',
      extendedRequestId: 'SkNgUIzCWTxHJ5c/IjKSR4Dp6Blo0Lf8OikHDWNqVKFEFMTS8uVwAMBZx9uWYS5+H65njWrZSv1KrjHPUQSNZODqtQ0Tf/l5y00UyKK7wD0=',
      cfId: undefined,
      attempts: 1,
      totalRetryDelay: 0
  },
  '$fault': 'client'

Expected Behavior

keep behaviour as expected - all errors from aws-sdk should be of type
S3ServiceException

Possible Solution

No response

Additional Information/Context

No response

[kuhe]

I'm not able to reproduce this. When I run

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

(async () => {
  const s3 = new S3({});
  await s3
    .getObject({
      Bucket: "(actual bucket)",
      Key: "1",
      IfNoneMatch: `"7ef740... (actual ETag) ...c0140"`,
    })
    .catch((e) => {
      console.log(e instanceof S3ServiceException);
      console.log(e.$metadata.httpStatusCode, e.name, e.message);
    });
})();

When object does not exist:

true
404 NoSuchKey The specified key does not exist.

When object matches ETag:

true
304 Unknown UnknownError

The true indicates that it does pass the instanceof check.

I've tried various versions of @aws-sdk/client-s3 at 3.931.0 and 3.932.0 (latest), along with various versions of transitive dependencies. Could you create a minimal repro repository on GitHub and share it here? The repro repository would help because I need a package-lock.json or equivalent lockfile that has the exact versions of all the code packages that are running.

[kuhe]

I think this may be due to nesting of the @smithy/core package. Please update your lockfile so that a single version of @smithy/core is present in your application.

It may help to install all AWS SDK clients at the same version, like this:

{
  "name": "your-app",
  "dependencies": {
    "@aws-sdk/client-s3": "<=3.933.0",
    "@aws-sdk/client-dynamodb": "<=3.933.0",
    "@aws-sdk/client-lambda": "<=3.933.0"
  }
}