s3 HeadObject still doesn't return types.NotFound error

[sachevl]

Describe the bug

issue #1049 claims to add NotFound as an error for HeadBucket and HeadObject methods. However proper error is not returned still

Expected Behavior

_, err := client.HeadObject(ctx, &s3.HeadObjectInput{
  Bucket: aws.String(bucketName),
  Key:    aws.String(key),
})
if err != nil {
  var nf *types.NotFound
  if errors.As(err, &nf) {   // <---------------- Expected to be true on http 404
  }
}

Current Behavior

Current behavior doesn't cast err to types.NotFound when object doesn't exist

Reproduction Steps

run the code from expected behavior against non existing s3 object

Possible Solution

Fix smithy model. Add unit tests to ensure correct error casting

Additional Information/Context

No response

AWS Go SDK V2 Module Versions Used

the latest

Compiler and Version used

go version go1.20.3 linux/amd64

Operating System and version

AL2

[RanVaknin]

Hi @sachevl ,

Thanks for opening the issue. I'm able to confirm this is an issue. This occurs because we parse the error type from the request body. Since HeadObject and HeadBucket requests don't return a body, the SDK should check the headers for the error type, and it doesn't do that yet.

This requires customization. I'll add to the backlog.

Thanks,
Ran~

[pkwarren]

I found this works as expected for HeadBucket, not for HeadObject. It appears the deserializer for HeadObject is missing this part:

aws-sdk-go-v2/service/s3/deserializers.go

Lines 6753 to 6754 in a86beba

	case strings.EqualFold("NotFound", errorCode):
	return awsRestxml_deserializeErrorNotFound(response, errorBody)

https://github.com/aws/aws-sdk-go-v2/blob/a86beba126393fdecee20c8d3fc6ef21064121f5/service/s3/deserializers.go#L6829C2-L6837

I think to preserve backwards compatibility, the SDK would need to continue wrapping the current error in types.NotFound (or the other way around). We're currently working around this issue with the following:

// Unfortunately HeadObject doesn't consistently wrap errors in s3.NotFound
// https://github.com/aws/aws-sdk-go-v2/issues/2084
var apiError smithy.APIError
if errors.As(err, &apiError) && apiError.ErrorCode() == "NotFound" {
	...
}

[github-actions]

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