Re: [gentoo-dev] [PATCH 2/6] profiles: enable USE="split-usr" in base

[Mike Gilbert]

On Sun, Jul 14, 2019 at 9:49 PM Michael Orlitzky <mjo@g.o> wrote:
>
> On 7/14/19 7:50 PM, Mike Gilbert wrote:
> >
> > +# Mike Gilbert <floppym@g.o> (2019-07-14)
> > +# Enable split-usr by default to keep systems working.
> > +USE="${USE} split-usr"
>
> A mandatory USE="keep-working" raises some philosophical red flags for
> me.

Yeah, that wording is bad. Maybe something like:

# Maintain split /usr for existing installs.

> Wouldn't it be better to name the flag "merge-usr" and leave the
> profile alone?

The "split-usr" flag is already being used by a few packages, so I
would like to keep it.

Another way to think about it: in the merged /usr case, ebuilds
generally do not need to do anything special: they can just copy their
files to $prefix (/usr). In the split /usr case, ebuilds need to do
special stuff like passing extra configure flags (--bindir, --libdir),
or calling gen_usr_ldscript to move libraries around.

The "split-usr" USE flag enables this special stuff. Having a
"merged-usr" USE flag would invert the meaning: disable the special
stuff if the flag is enabled. We generally try to avoid inverted flags
like this (a notable exception being the "vanilla" USE flag).

>  (This will be especially bad for the people who start with USE="-*")

As has been previously mentioned, we don't generally recommend this
for people who don't know what they are doing. In any case, I think
they would have already run into problems given that baselayout has
had IUSE="+split-usr" for at least several months.

A possible solution would be to add split-usr to use.force in the base
profile, and un-force it in some new profile we create at a later
date. Do people think this is warranted?