[gentoo-user] Re: Portage performance dropped considerably

[Martin Vaeth <martin@mvath.de>]

hasufell <hasufell@gentoo.org> wrote:
>
> On 01/27/2014 12:26 AM, William Hubbs wrote:
>>
>> No, starting with USE="-*" is very dangerous.
>
> That's nonsense imo

No, William is completely right.

> and I use that setup on multiple servers/routers without any issues.

No one doubts that it is *possible* to add the correct USE for
every single package manually, but it is not a good idea to hide
the recommended defaults.

> It makes sense because you have the most minimal setup possible

This is not true, to start with: For instance, USE=minimal will
usually choose a more minimal setup.
With "-*" you will actually *disable* the default USE=minimal
for e.g. www-client/firefox, x11-apps/startx, sys-block/blocks,
dev-db/unixODBC, ... and thus get a setup which is even larger
than the recommended default.

> most minimal codepaths possible which reduces exposure to bugs.

No, you usually get less tested (and by upstream considered untypical)
codepaths which actually increases the probability to hit a bug
nobody did hit/test yet.

The USE="-*" approach was reasonable before EAPI=1 was introduced:
In these days, unusual codepaths would have been set by "negative"
USE-flags, e.g. IUSE="nocxx" for gcc.
Nowadays, the upstream-recommended codepaths are set by default-USE-Flags
in the ebuild, i.e. now the same is called IUSE="+cxx" in gcc.
Using -* you disable such defaults which are usually there for a
good reason.

Of course, if you know and care what every single USE-flags for every
single package does, it does not matter much which approach you take,
but I would guess that even in this case you need more exceptions
in /etc/portage/package.use with USE="-*" than with USE="".

Moreover, even for updates, it happens occassionally that a package
gets an additional USE-flag, whose default is then usually chosen in
such a way as the behaviour was before - so you risk dropping
crucial behaviour on updates if you are not very careful.