overlay eclass overrides eclass from PORTDIR: what is it?
* Overlay eclass overrides eclass from PORTDIR:
Could anyone explain me what does it mean in practice?
The cause of this message is that one of the overlays you
have configured includes an eclass that already exists in
base portage. This happens when the overlay includes
ebuilds that require enhanced behavior from a current eclass.
The result of this message is that portage is going to run
slower than normal unless you do what the error recommends.
The short explanation is:
When you sync to a portage mirror, you download a set of
metadata cache files that were pre-generated and saved on
the mirror, that portage can use to build the dependancy
list. But the metadata cache is only valid if it has been
built using the exact same eclasses as you have locally;
changing an eclass could (potentially) alter the dependancy
graph. So when portage notices that your metadata is
outdated, it will stop using it and get slower.
If you run "emerge --regen" every time you sync, portage
rebuilds the metadata cache locally, with your copies of the
eclass files. This takes a *long* time (it takes 6+ hours
on some of my slower machines) but once it has been done,
portage will run faster.
There's nothing you can do to avoid the problem other than
not using the overlay in question.