'emerge -v1 openfoam' fails with: ... root@impala:/usr/local/portage/sci-libs(74)# emerge -v1 openfoam These are the packages that would be merged, in order: Calculating dependencies... done! [ebuild UD ] dev-libs/jsoncpp-0.10.6:0/0::gentoo [1.8.0:0/11::gentoo] USE="doc {-test}" 0 KiB [ebuild N ] sci-visualization/paraview-5.2.0::gentoo USE="boost cg development doc examples ffmpeg mpi mysql openmp plugins python qt5 sqlite tcl tk -coprocessing -nvcontrol {-test}" PYTHON_TARGETS="python2_7" 0 KiB [ebuild R ] sci-libs/openfoam-2.4.0-r1:2.4::gentoo USE="doc examples opendx paraview -src" 0 KiB Total: 3 packages (1 downgrade, 1 new, 1 reinstall), Size of downloads: 0 KiB !!! Multiple package instances within a single package slot have been pulled !!! into the dependency graph, resulting in a slot conflict: dev-libs/jsoncpp:0 (dev-libs/jsoncpp-0.10.6:0/0::gentoo, ebuild scheduled for merge) pulled in by <dev-libs/jsoncpp-1.7.5 required by (sci-visualization/paraview-5.2.0:0/0::gentoo, ebuild scheduled for merge) ^ ^^^^^ (dev-libs/jsoncpp-1.8.0:0/11::gentoo, installed) pulled in by dev-libs/jsoncpp:0/11= required by (dev-qt/qtwebengine-5.7.1-r1:5/5.7::gentoo, installed) ^^^^^^ (and 1 more with the same problem)
You should be able to work around this by adding qtwebengine to the package list.
dup of bug #608158?
(In reply to Juergen Rose from comment #0) > root@impala:/usr/local/portage/sci-libs(74)# emerge -v1 openfoam The problem is that you need to perform updates like this with --update --deep @world, since "partial" updates like this are not really supported until bug 559354 has been implemented. The problem is that emerge doesn't trigger the necessary rebuilds because it assumes you don't want them, and we currently don't have a way to tell it differently, except by using --update --deep @world. (In reply to Michael Palimaka (kensington) from comment #2) > dup of bug #608158? Only if it fails with --update --deep @world.
For the dev-libs/jsoncpp downgrade to proceed, you'll have to mask >=dev-libs/jsoncpp-1.7.5 in /etc/portage/package.mask. If you don't do that, emerge will always pull in the newer version of jsoncpp, in order to ensure that it doesn't miss an update to a new version.
Downgrade support was added in this commit for bug 424651: https://gitweb.gentoo.org/proj/portage.git/commit/?id=02bcf332a88bbf25b9e0391b1a6d781ab4bbe0b9
*** This bug has been marked as a duplicate of bug 424651 ***
