Description of problem: $ TMPDIR=. guestfish -a /dev/null run guestfish: launch-libvirt.c:1172: make_qcow2_overlay: Assertion `path[0] == '/'' failed. Aborted TMPDIR isn't supposed to be a relative path. There are three possible things we could do here: (a) When parsing the environment, turn it into an absolute path. (b) Still fail, but have a better diagnostic. (c) Document it. Version-Release number of selected component (if applicable): libguestfs 1.19.65
Fixed upstream: https://github.com/libguestfs/libguestfs/commit/6b5f9221b4fa5842c428e4258205c39295203127