Remove the Body of PUT requests for 0-length files

core/internal/filetransfer/file_transfer_default.go

@@ -94,6 +94,14 @@ func (ft *DefaultFileTransfer) Upload(task *Task) error {
  if err != nil {
  return err
  }
+ if task.Size == 0 {
+ // *Sometimes* on *some* platforms, req.Body is set to a non-nil io.Reader that
+ // would return 0 bytes if read, but net/http/Request.outgoingLength takes the
+ // presence of a body to indicate that length > 0 and "corrects" it to -1 to
+ // indicate unknown. If we don't fix it here we get 411 Length Required errors.
+ req.Body = nil
+ task.Headers = append(task.Headers, "Content-Length:0")
+ }
  for _, header := range task.Headers {
  parts := strings.SplitN(header, ":", 2)
  if len(parts) != 2 {