Some ebuilds need very nasty arch-useflag (e.g. x86) DEPENDs. This seems to stem from their herds experiencing the dependency resolution output of portage to be insufficient, in case it could not work out a way to resolve dependencies of a package.
Hence I propose an output similar to:
Unable to resolve dependencies for foo/bar-1, the options were:
* xxx/yyy-1 masked by: package.mask
* xxx/yyy-2 masked by: missing keyword
* aaa/bbb-9.1 masked by ~x86
So a little bit like what Debian's Aptitude does: Present multiple solutions to resolve a problem. The user then sees immediately where portage got stuck and can hopefully adjust their /etc/portage files accordingly.
The example assumes that the file foo/bar/bar-1.ebuild would contain:
DEPEND="|| ( xxx/yyy:0 =aaa/bbb-9* )"
And the files xxx/yyy/yyy-1.ebuild, xxx/yyy/yyy-2.ebuild, aaa/bbb/bbb-9.1.ebuild would exist with abovementioned masks and slots.
Maybe it would help if we added support for package.mask and missing keywords to the emerge --autounmask option? Currently it only supports unstable keywords.
My point mainly was that currently it is hard to figure out how portage came to the conclusion that this or that package cannot be emerged.
E.g. what virtual/jdk-1.6.0 does is this:
# Keeps this and java-virtuals/jaf in sync
# The keyword voodoo below is needed so that ppc(64) users will
# get a masked license warning for ibm-jdk-bin
# instead of (not useful) missing keyword warning for sun-jdk
# see #287615
# note that this "voodoo" is pretty annoying for Prefix, and that we didn't
# invent it in the first place!
amd64? ( dev-java/icedtea6-bin )
x86? ( dev-java/icedtea6-bin )
amd64? ( =dev-java/sun-jdk-1.6.0* )
x86? ( =dev-java/sun-jdk-1.6.0* )
The arch-useflags look horrible, and prevent testing on other arches. And all that only because it is difficult for users to see the information that helps them.
(In reply to comment #2)
> # The keyword voodoo below is needed so that ppc(64) users will
> # get a masked license warning for ibm-jdk-bin
> # instead of (not useful) missing keyword warning for sun-jdk
> # see #287615
This probably refers to bug #287615 comment #16, where portage says that dev-java/icedtea6-bin was masked, but not what other options it found to be insufficient before it arrived there.