Created attachment 545114 [details] test-suite.log error: socket path "/mnt/portagetmp/portage/dev-libs/wayland-1.15.0/temp/xdr/wayland-tests-qj3dS0/wayland-test-31730-1535286591751424" plus null terminator exceeds 108 bytes display-test: /mnt/portagetmp/portage/dev-libs/wayland-1.15.0/work/wayland-1.15.0/tests/test-compositor.c:334: display_create: Assertion `stat == 0 && "Failed adding socket"' failed. test "zombie_fd_errant_consumption": signal 6, fail. and several more tests with the same error
Created attachment 545116 [details] build.log
Created attachment 545118 [details] emerge --info
Over a year ago I made it work for /var/tmp/portage, when the path is very close to too long (so with a -r1 it was too long and tests fails). That's why you see a hort "temp/xdr" in there. But "/mnt/portagetmp/portage" is even longer than "/var/tmp/portage" (23 vs 16 chars), and we'd enter the territory of either forcing /tmp instead of PORTAGE_TMPDIR or having upstream use shorter paths in their part of the full path (then it'll still be a problem, just with even longer PORTAGE_TMPDIR). Doing both of these was more effort and unsure of sandbox and other concerns. Maybe /tmp is possible, but there will be concerns of cleanup (PORTAGE_TMPDIR gets cleaned up by portage, not so with /tmp) and so on. I suggest a shorter PORTAGE_TMPDIR (perhaps a symlink from a shorter path to your mount). Personally I use PORTAGE_TMPDIR=/tmp and don't hit this issue anymore thanks to the shorter xdr/ path.
