Traceback (most recent call last):


 "/Users/igortkachenko/Tools/kivy-designer/venv/lib/python3.6/site-packages/kivy/uix/widget.py", line 265, in _widget_destructor


 "/Users/igortkachenko/Tools/kivy-designer/venv/lib/python3.6/site-packages/kivy/lang/builder.py", line 760, in unbind_widget


 "kivy/weakproxy.pyx", line 30, in kivy.weakproxy.WeakProxy.__getattr__
AttributeError: 'weakref' object has no attribute 'cline_in_traceback'

Traceback (most recent call last):


 "/home/jeg/spack/bin/spack", line 212, in <module>

main(sys.argv)


 "/home/jeg/spack/bin/spack", line 208, in main

_main(args, unknown)


 "/home/jeg/spack/bin/spack", line 174, in _main

return_val = command(parser, args)


 "/home/jeg/spack/lib/spack/spack/cmd/mirror.py", line 224, in mirror

action[args.mirror_command](args)


 "/home/jeg/spack/lib/spack/spack/cmd/mirror.py", line 202, in mirror_create

directory, specs, num_versions=args.one_version_per_spec)


 "/home/jeg/spack/lib/spack/spack/mirror.py", line 167, in create

s.concretize()


 "/home/jeg/spack/lib/spack/spack/spec.py", line 1527, in concretize

self._expand_virtual_packages(),


 "/home/jeg/spack/lib/spack/spack/spec.py", line 1422, in _expand_virtual_packages

self_index = ProviderIndex(self.traverse(), restrict=True)


 "/home/jeg/spack/lib/spack/spack/provider_index.py", line 87, in __init__

self.update(spec)


 "/home/jeg/spack/lib/spack/spack/provider_index.py", line 104, in update

if spec.satisfies(provider_spec, deps=False):


 "/home/jeg/spack/lib/spack/spack/spec.py", line 2054, in satisfies

if not self.variants.satisfies(other.variants, strict=var_strict):


 "/home/jeg/spack/lib/spack/spack/spec.py", line 633, in satisfies

if strict or self.spec._concrete:
AttributeError: 'NoneType' object has no attribute '_concrete'
