when we have a Packages index, we have sizes/digests of all the binpkgs. so if i start d/l-ing some and CTRL+C the process, it isn't uncommon for some binpkgs to be left in a partial state. the next time i run emerge, it complains like: !!! Invalid binary package: '.../x11-proto/xf86dgaproto-2.1.tbz2' !!! Missing metadata key(s): CATEGORY, PF, SLOT. This binary package is not !!! recoverable and should be deleted. if portage finds an invalid binpkg and its sizes do not match, try to resume it. if it still fails, it should use the same logic as distfiles where we rename it with a "_checksum_failure_" suffix and then try to refetch. we could put this behind a flag or FEATURE, but i'm not sure we need to bother since we don't rm the file and this is behavior that people should generally want (when used in combination with Packages).