Unexpected behavior on DeleteObjects request

[grsw92]

Describe the bug

Hi,

I recently noticed rather inconsistent behavior while using DeleteObjects command.

Example scenario: Sending DeleteObjects request where one of the files has invalid key (too long in my case). The client throws AmazonS3Exception where I believe the DeleteObjectsException should be thrown instead. Moreover the valid object keys listed in the request are not deleted.

I haven't seen any remarks for this particular case in the documentation to this method.

Regression Issue

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

Expected Behavior

When one of the keys is invalid the DeleteObjectsException should be thrown and the objects under valid keys should be deleted.

Current Behavior

When one of the keys is invalid the AmazonS3Exception is thrown and none of the objects is deleted.

Reproduction Steps

See this little sample which reproduces the problem:

// upload valid object
var content = Guid.NewGuid().ToString();
await s3Client.PutObjectAsync(new PutObjectRequest
{
    BucketName = bucket,
    Key = key,
    InputStream = new MemoryStream(Encoding.UTF8.GetBytes(content)),
    AutoCloseStream = true
}, cancellationToken);

// generate invalid key which should result KeyTooLongError
var invalidObjectKey = string.Join(string.Empty, Enumerable.Repeat("a", 1025));

// delete objects
var deleteObjectsRequest = new DeleteObjectsRequest { BucketName = bucket };

deleteObjectsRequest.AddKey(key);
deleteObjectsRequest.AddKey(invalidObjectKey);

try
{
    await s3Client.DeleteObjectsAsync(deleteObjectsRequest, cancellationToken);
}
catch (DeleteObjectsException e)
{
    Console.WriteLine("This is expected! {0}", e);
} 
catch (AmazonS3Exception e)
{
    Console.WriteLine("This is not expected! {0}", e);
}

// the valid file should be deleted
var response = await s3Client.ListObjectsAsync(bucket, key, cancellationToken);
Console.WriteLine(response.S3Objects.Any() ? "Object found. This is not expected" : "Object deleted. This is expected");

Possible Solution

No response

Additional Information/Context

No response

AWS .NET SDK and/or Package version used

AWSSDK.S3 4.0.0.5
AWSSDK.S3 3.7.416.29

Targeted .NET Platform

.NET 8

Operating System and version

Ubuntu

[AlexDaines]

Hi @grsw92, thank you for bringing this issue to our attention.

I've confirmed the issue by reproducing both reported behaviors:

1. When DeleteObjects includes an invalid key (too long), it throws AmazonS3Exception instead of DeleteObjectsException
2. The valid object keys in the request are not deleted

Our investigation shows that client-side validation is rejecting the entire batch when any key is invalid, rather than allowing the service to process valid keys.

We're working on a fix to properly handle this scenario and will update this issue with a PR soon.