With no_head_object set, NewObject does not read any metadata, so the
destination object returned from a server side copy had a size of 0.
The size check in operations.Copy then failed with "corrupted on
transfer: sizes differ N vs 0" and deleted the newly copied object.
This also broke Move and hence renames through rclone mount.
Populate the destination object's size and MD5 from the source object
when no_head_object is set, as a server side copy produces an object
with identical content.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
