【cap | rails】cap deployでtar: This does not look like a tar archiveのとき

rails で capistarnoでのdeployをしているときに

 DEBUG [b12800e2]    fatal: Not a valid object name
 DEBUG [b12800e2]   tar: This does not look like a tar archive
 DEBUG [b12800e2]   tar: Exiting with failure status due to previous errors

とかなったら、多分、まだ対象branchがremoteにないので pushするなりしよう