Re: [gentoo-dev] [PATCH] ebuild-writing/variables: better describe ROOT

[Brian Dolbec]

On Tue, 10 May 2016 21:42:19 -0400
Mike Gilbert <floppym@g.o> wrote:

> On Tue, May 10, 2016 at 5:25 PM, Michael Orlitzky <mjo@g.o>
> wrote:
> > On 05/10/2016 02:28 PM, Mike Gilbert wrote:
> >> On Tue, May 10, 2016 at 11:08 AM, Michael Orlitzky
> >> <mjo@g.o> wrote:
> >>> We have maybe 150 ebuilds in the tree using $ROOT in src_*
> >>> functions. Some are bugs, but many look OK to me. Do we really
> >>> want to say "never" do that?
> >>
> >> According to PMS, it is only legal in pkg functions.
> >>
> >> Can you point to an example where using ROOT in a src function is
> >> appropriate?
> >
> > Modulo the question "when should you use $ROOT over $EPREFIX"...
> >
> >   * the chrome-binary-plugins ebuilds use it in src_install.
>
> This is quite obviously wrong. I happen to maintain that ebuild, so I
> just fixed.
>
> >   * dmraid does
> >
> >       einfo "Appending pkg.m4 from system to aclocal.m4"
> >       cat "${ROOT}"/usr/share/aclocal/pkg.m4 >>"${S}"/aclocal.m4 ||
> > \ die "Could not append pkg.m4
>
> This should be one of two things:
>
> cat /usr/share/aclocal/pkg.m4
>
> Or, if prefix support is desired:
>
> cat "${EPREFIX}"/usr/share/aclocal/pkg.m4
>
> > Both of those look like EPREFIX candidates to me, but they're not
> > obviously wrong, either. Maybe it made sense in EAPI <= 3.
> >
> > Anywhere that you need addpredict() it also seems reasonable. The
> > v4l-dvb-saa716x ebuilds use "${ROOT}/usr/src/linux/" where EPREFIX
> > would not be a good replacement.
>
> Nah, usually addpredict is dealing with stuff in the system that is
> performing the build. Sandboxed phases should never be looking at
> ROOT.
>
> Those ebuilds should probably do addpredict /usr/src/linux instead.
>
> >
> > Something needs to be fixed, though: you're right that the PMS
> > limits ROOT to pkg_*. Who knew? If we want to be serious about
> > banning ROOT in src_*, we should add a repoman error.
>
> Based on my own understanding of the ROOT variable, its use in src
> functions is always nonsensical, especially when you consider binpkgs.
> A binpkg can be installed with a ROOT value that is completely
> different from its value when the package is being compiled.
>
> To put it another way, in src functions, ROOT could/should always be
> "/". The real value of ROOT isn't determined until merge time.
>
> I agree, repoman should be catching this stuff.
>

Then Please contribute some test ebuilds for the gen-b0rk repo to test
repoman or any other Q/A apps with.  If they fail to detect the test
ebuilds, it will give us something to use to help trace the code errors.
It'll also make for a much better testing system overall for any app
performing any type of Q/A on ebuilds.


-- 
Brian Dolbec <dolsen>