After updating to 2.1.5_rc7 (from rc6) i've noticed that package list for 'emerge -pv virtualbox' is printed twice. It looks like this: root@box ~ # emerge -pv virtualbox These are the packages that would be merged, in order: Calculating dependencies... done! [ebuild N ] sys-devel/bin86-0.16.17 149 kB [ebuild N ] sys-power/iasl-20060912 840 kB [ebuild N ] net-misc/bridge-utils-1.2 32 kB [ebuild N ] sys-apps/usermode-utilities-20070815 49 kB [ebuild N ] sys-kernel/gentoo-sources-2.6.25-r2 USE="symlink -build" 56 kB [ebuild UD] dev-libs/icu-3.6-r2 [3.8.1-r1] USE="-debug (-doc%) (-examples%)" 9,945 kB [ebuild N ] dev-libs/xerces-c-2.7.0-r1 USE="-doc" 7,579 kB [ebuild N ] dev-libs/xalan-c-1.10.0 USE="-doc" 1,519 kB [ebuild N ] sys-devel/dev86-0.16.17-r5 687 kB [ebuild N ] dev-libs/xerces-c-2.8.0 USE="iconv icu threads -debug -doc -libwww" 7,709 kB [ebuild N ] app-emulation/virtualbox-modules-1.5.7 198 kB [ebuild N ] app-emulation/virtualbox-1.5.6 USE="alsa -additions -pulseaudio -sdk" 26,095 kB Total: 12 packages (1 downgrade, 11 new), Size of downloads: 54,853 kB [ebuild N ] sys-devel/bin86-0.16.17 149 kB [ebuild N ] sys-power/iasl-20060912 840 kB [ebuild N ] net-misc/bridge-utils-1.2 32 kB [ebuild N ] sys-apps/usermode-utilities-20070815 49 kB [ebuild N ] sys-kernel/gentoo-sources-2.6.25-r2 USE="symlink -build" 56 kB [ebuild UD] dev-libs/icu-3.6-r2 [3.8.1-r1] USE="-debug (-doc%) (-examples%)" 9,945 kB [ebuild N ] dev-libs/xerces-c-2.7.0-r1 USE="-doc" 7,579 kB [ebuild N ] dev-libs/xalan-c-1.10.0 USE="-doc" 1,519 kB [ebuild N ] sys-devel/dev86-0.16.17-r5 687 kB [ebuild N ] dev-libs/xerces-c-2.8.0 USE="iconv icu threads -debug -doc -libwww" 7,709 kB [ebuild N ] app-emulation/virtualbox-modules-1.5.7 198 kB [ebuild N ] app-emulation/virtualbox-1.5.6 USE="alsa -additions -pulseaudio -sdk" 26,095 kB Total: 12 packages (1 downgrade, 11 new), Size of downloads: 54,853 kB !!! Multiple versions within a single package slot have been pulled !!! into the dependency graph, resulting in a slot conflict: dev-libs/xerces-c:0 ('ebuild', '/', 'dev-libs/xerces-c-2.7.0-r1', 'merge') pulled in by ('ebuild', '/', 'dev-libs/xalan-c-1.10.0', 'merge') ('ebuild', '/', 'dev-libs/xerces-c-2.8.0', 'merge') pulled in by ('ebuild', '/', 'app-emulation/virtualbox-1.5.6', 'merge') It may be possible to solve this problem by using package.mask to prevent one of those packages from being selected. However, it is also possible that conflicting dependencies exist such that they are impossible to satisfy simultaneously. If such a conflict exists in the dependencies of two different packages, then those packages can not be installed simultaneously. For more information, see MASKED PACKAGES section in the emerge man page or refer to the Gentoo Handbook. Probably it's caused by the need of downgrade (I actually haven't found any other package that shows similar bug - but none of tested needed downgrade). Anyway, with rc6 list of packages was shown once - and downgrading portage solves this problem.
This is fixed in 2.1.5_rc9.
