If a non-existing dir in the PORTDIR_OVERLAY string is specified in make.conf I got: !!! Invalid PORTDIR_OVERLAY (not a dir): '/usr/local/portage/lefous-overlay' !!! Invalid PORTDIR_OVERLAY (not a dir): '/usr/local/portage/lefous-overlay' Shouldn't emerge either stop after the first failure or skip the 2nd warning ?
Portage has lots of warnings that can print any number of times like that. It's not really worth the effort to ensure that such messages are only displayed once. The point is to annoy the user such that they'll correct the problem ASAP.