What's the issue?

When using the new optional since_last_modified parameter in cases where there are no new files, the return value of the function is the entire sorted list when it should be an empty list. To fix:

if since_last_modified:
        for idx, obj in enumerate(sorted_objects):
            if obj.get("LastModified") > since_last_modified:
                return sorted_objects[idx:]
        return []

What did you expect to happen?

To return an empty list representing that there are no new s3 objects uploaded since the provided timestamp.

How to reproduce?

Query an S3 source with no new objects since a provided timestamp.

Dagster version

dagster, version 1.8.13

Deployment type

Dagster Cloud

Deployment details

No response

Additional information

PR for fix

Message from the maintainers

Impacted by this issue? Give it a 👍! We factor engagement into prioritization.
By submitting this issue, you agree to follow Dagster's Code of Conduct.