fix(services/s3): Accept List responses without ETag

[amunra]

This allows the S3 logic to accept response for path listings that don't contain the optional <ETag> xml element.

The bug was originally observed when connecting to an S3 compatible server: s3s-fs (https://crates.io/crates/s3s-fs).

I believe s3s-fs's behaviour is correct, given that the AWS S3 request/response docs state that the Etag field is optional: https://docs.aws.amazon.com/AmazonS3/latest/API/API_Object.html.

Closes #3477.

[Xuanwo]

I believe s3s-fs's behaviour is correct, given that the AWS S3 request/response docs state that the Etag field is optional

I don't think this statement is correct since Key is this doc is also Required: no. And we know that it's impossible.

I'm ok with this patch to allow responses that not contain ETag. But I want to let you know that all s3 compatible services return ETag.

[amunra]

I believe s3s-fs's behaviour is correct, given that the AWS S3 request/response docs state that the Etag field is optional

I don't think this statement is correct since Key is this doc is also Required: no. And we know that it's impossible.

I'm ok with this patch to allow responses that not contain ETag. But I want to let you know that all s3 compatible services return ETag.

Fair :-)

For what it's worth, the official AWS Java client is flexible about this too and doesn't require the ETag either: Thank you for accepting this change!

[Xuanwo]

Thanks!