Cleanbuild fail on 18.04 with lxd 3.0

Today I upgraded my lxd package to 3.0.0-0ubuntu1 and snapcraft cleanbuild fail with:

[...]
Setting up squashfuse (0.1.100-0ubuntu1~ubuntu16.04.1) ...
Looking up assertion ['account-key', 'public-key-sha3-384=BWDEoaqyr25nF5SNCvEv2v7QnM9QsfCc0PBMYD_i2NGSQ32EF2d4D0hqUel3m8ul']
Looking up assertion ['snap-declaration', 'snap-name=core']
Looking up assertion ['snap-revision', 'snap-revision=4206', 'snap-id=99T7MUlRhtI3U0QFgl5mXXESAiSwt776']
Error: not found
Stopping local:snapcraft-nongerundively-deft-rene
Traceback (most recent call last):
  File "/snap/snapcraft/1345/bin/snapcraft", line 11, in <module>
    load_entry_point('snapcraft==2.40.1', 'console_scripts', 'snapcraft')()
  File "/snap/snapcraft/1345/usr/lib/python3.6/site-packages/pkg_resources/__init__.py", line 565, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/snap/snapcraft/1345/usr/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2631, in load_entry_point
    return ep.load()
  File "/snap/snapcraft/1345/usr/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2291, in load
    return self.resolve()
  File "/snap/snapcraft/1345/usr/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2297, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/cli/__main__.py", line 43, in <module>
    run(prog_name='snapcraft')
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/click/core.py", line 1066, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/cli/lifecycle.py", line 218, in cleanbuild
    lifecycle.cleanbuild(project_options, remote)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lifecycle/_containers.py", line 68, in cleanbuild
    metadata=config.get_metadata(), remote=remote).execute()
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lxd/_containerbuild.py", line 168, in execute
    with self._container_running():
  File "/snap/snapcraft/1345/usr/lib/python3.6/contextlib.py", line 82, in __enter__
    return next(self.gen)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lxd/_containerbuild.py", line 79, in _container_running
    with self._ensure_started():
  File "/snap/snapcraft/1345/usr/lib/python3.6/contextlib.py", line 82, in __enter__
    return next(self.gen)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lxd/_containerbuild.py", line 102, in _ensure_started
    self._ensure_container()
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lxd/_cleanbuilder.py", line 50, in _ensure_container
    self._inject_snapcraft(new_container=True)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lxd/_containerbuild.py", line 230, in _inject_snapcraft
    self._inject_snap('core', tmp_dir)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lxd/_containerbuild.py", line 290, in _inject_snap
    ], tmp_dir)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lxd/_containerbuild.py", line 363, in _inject_assertions
    self._push_file(filepath, container_filename)
  File "/snap/snapcraft/1345/lib/python3.6/site-packages/snapcraft/internal/lxd/_containerbuild.py", line 312, in _push_file
    src, '{}{}'.format(self._container_name, dst)])
  File "/snap/snapcraft/1345/usr/lib/python3.6/subprocess.py", line 291, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['lxc', 'file', 'push', '/home/guilhem/snap/lxd/common/snapcraft4cvhs7rl/core_4206.assert', 'local:snapcraft-nongerundively-deft-rene/run/core_4206.assert']' returned non-zero exit status 1.

Note that I’m using lxd package and not snap (refering to /home/guilhem/snap/lxd/ folder in log)

This seems to be LP: #1746612, which is a bug in LXD.