git-annex 7.20190129 released with these changes

  • initremote S3: When configured with versioning=yes, either ask the user to enable bucket versioning, or auto-enable it when built with aws-0.22.
  • enableremote S3: Do not let versioning=yes be set on existing remote, because when git-annex lacks S3 version IDs for files stored in the bucket, deleting them would cause data loss.
  • S3: Detect when version=yes but an exported file lacks a S3 version ID, and refuse to delete it, to avoid data loss.
  • S3: Send a Content-Type header when storing objects in S3, so exports to public buckets can be linked to from web pages. (When git-annex is built with MagicMime support.)