Hi, by coincidence I was also working on zfs support in schroot today and randomly found this fresh patch.
I have no C++ skills and was just doing custom type, but concept is the same. It's a log not from a debian system, but maybe this will be useful in polishing this patch Details: all debian patches applied ppc64le gcc-9.2.0 boost 1.72.0 Error: [ 61%] Built target dchroot-common [ 63%] Building CXX object sbuild/CMakeFiles/sbuild.dir/sbuild-chroot-facet-union.cc.o cd /var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10_build/sbuild && /usr/bin/powerpc64le-unknown-linux-gnu-g++ -I/var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10_build/lib -I/var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10/lib -I/var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10_build -I/var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10 -I/var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10/sbuild -I/var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10_build/sbuild -DNDEBUG -mcpu=native -O2 -pipe -frecord-gcc-switches -fdiagnostics-show-option -std=c++11 -pedantic -Wall -Wcast-align -Wwrite-strings -Wswitch-default -Wcast-qual -Wunused-variable -Wredundant-decls -Wctor-dtor-privacy -Wnon-virtual-dtor -Wreorder -Wold-style-cast -Woverloaded-virtual -fstrict-aliasing -o CMakeFiles/sbuild.dir/sbuild-chroot-facet-union.cc.o -c /var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10/sbuild/sbuild-chroot-facet-union.cc /var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10/sbuild/sbuild-chroot-zfs-snapshot.cc: In member function 'virtual sbuild::chroot::ptr sbuild::chroot_zfs_snapshot::clone_source() const': /var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10/sbuild/sbuild-chroot-zfs-snapshot.cc:93:42: error: 'sbuild::chroot_block_device::chroot_block_device(const sbuild::chroot_zfs_snapshot&)' is protected within this context 93 | ptr clone(new chroot_block_device(*this)); | ^ In file included from /var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10/sbuild/sbuild-chroot-zfs-snapshot.cc:23: /var/tmp/portage/dev-util/schroot-1.6.10-r5/work/schroot-1.6.10/sbuild/sbuild-chroot-block-device.h:55:5: note: declared protected here 55 | chroot_block_device (const chroot_zfs_snapshot& rhs); | ^~~~~~~~~~~~~~~~~~~ make[2]: *** [sbuild/CMakeFiles/sbuild.dir/build.make:466: sbuild/CMakeFiles/sbuild.dir/sbuild-chroot-zfs-snapshot.cc.o] Error 1 make[2]: *** Waiting for unfinished jobs.... Regards, Georgy.