As of upstream commit 2211a951e "[kcmkwin] Split out Desktop Effects KCM", the kcmkwin/kwincompositing/qml/Effect.qml file that kwin-gstreamer-optional.patch attempts to patch no longer exists, with the predicted result (prep phase failure due to patch failure due to missing target file) when the ebuild attempts to apply the patch. I don't yet know whether the patch needs regenerated against something else (as "split" would imply) or whether it's unnecessary now, as I'm filing this straight off the error, before trying to rebuild without the patch.
(In reply to Duncan from comment #0) > I don't yet know whether the patch needs regenerated against something else > (as "split" would imply) or whether it's unnecessary now, as I'm filing this > straight off the error, before trying to rebuild without the patch. Seems to be unnecessary here, with USE=-multimedia so presumably before it would have triggered an error without the patch. But kwin merges just fine without that line in the ebuild, and the effects and compositing kcms both load just fine afterward (tho I've not rebooted yet).
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/proj/kde.git/commit/?id=629e28dccb9f78c9c2d8dcc5d2bf65267cc4c026 commit 629e28dccb9f78c9c2d8dcc5d2bf65267cc4c026 Author: Andreas Sturmlechner <asturm@gentoo.org> AuthorDate: 2019-03-22 22:10:36 +0000 Commit: Andreas Sturmlechner <asturm@gentoo.org> CommitDate: 2019-03-22 22:10:36 +0000 kde-plasma/kwin: Rebase gstreamer-optional.patch Closes: https://bugs.gentoo.org/681238 Package-Manager: Portage-2.3.62, Repoman-2.3.12 Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org> kde-plasma/kwin/files/kwin-5.15.80-gstreamer-optional.patch | 13 +++++++++++++ kde-plasma/kwin/kwin-9999.ebuild | 2 +- 2 files changed, 14 insertions(+), 1 deletion(-)