# Buggy code
def __exit__(self, exc_type, exc_val, exc_tb):
    """
    Exiting from a stage context will delete the stage directory unless:
    - it was explicitly requested not to do so
    - an exception has been raised

    Args:
        exc_type: exception type
        exc_val: exception value
        exc_tb: exception traceback

    Returns:
        Boolean
    """
    # Delete when there are no exceptions, unless asked to keep.
    if exc_type is None and not self.keep:
        self.destroy()


# Traceback (KeyError)
==> Installing cactusext
==> openmpi is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/openmpi-2.0.0-5l3pomaqonrx3phvbm4kblzsms56ljtj
==> hwloc is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/hwloc-1.11.3-xgdwohjb2o26uftzaqtcmwf2ejxlhidw
==> git is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/git-2.8.1-jh72meyfuritl2wexqmckrshmufe7az4
==> papi is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/papi-5.4.3-tnovpyennp4cerqns4xnfscfvl6d3zlz
==> hdf5-blosc is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/hdf5-blosc-master-6m7xtyqubxsb2merc36i2oyhtdvno3zp
==> lmod is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/lmod-6.4.1-i2xu3l63aipam7bdlu3ig4eriqtjnbbd
==> hdf5 is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/hdf5-1.10.0-patch1-jfa4zar7ysebuadia7zlhoebrlaeo5lv
==> python is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/python-2.7.11-y6bfneoxof25qt6wgdsbfsra62grfdnz
==> lua is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/lua-5.3.2-xe6niqb4cwgkdpq33qjoi3rby3vcdnew
==> fftw is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/fftw-3.3.4-ojokm7aahpro46e4tvoqgsc57lzbfdum
==> openssl is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/openssl-1.0.2h-ookfh4fsbv5ijqjsewerc5vvf4hzfme6
==> julia is already installed in /home/ux452368/comet/src/spack/opt/spack/linux-centos6-x86_64/gcc-6.1.0-spack/julia-master-bzqdzwekzl3geaeyuexssnelbnwfiwsf
Traceback (most recent call last):
File "/home/ux452368/comet/src/spack/bin/spack", line 179, in <module>
main()
File "/home/ux452368/comet/src/spack/bin/spack", line 157, in main
return_val = command(parser, args)
File "/home/ux452368/comet/src/spack/lib/spack/spack/cmd/install.py", line 91, in install
explicit=True)
File "/home/ux452368/comet/src/spack/lib/spack/spack/package.py", line 943, in do_install
run_tests=run_tests)
File "/home/ux452368/comet/src/spack/lib/spack/spack/package.py", line 1096, in do_install_dependencies
dep.package.do_install(**kwargs)
File "/home/ux452368/comet/src/spack/lib/spack/spack/package.py", line 925, in do_install
rec = spack.installed_db.get_record(self.spec)
File "/home/ux452368/comet/src/spack/lib/spack/spack/database.py", line 76, in converter
return function(self, spec_like, *args, **kwargs)
File "/home/ux452368/comet/src/spack/lib/spack/spack/database.py", line 461, in get_record
key = self._get_matching_spec_key(spec, **kwargs)
File "/home/ux452368/comet/src/spack/lib/spack/spack/database.py", line 456, in _get_matching_spec_key
raise KeyError("No such spec in database! %s" % spec)
KeyError: 'No such spec in database! julia@master%gcc@6.1.0-spack+binutils~cxx+hdf5+mpi~plot~python arch=linux-centos6-x86_64^binutils@2.25%gcc@6.1.0-spack+gold~krellpatch~libiberty arch=linux-centos6-x86_64^bzip2@1.0.6%gcc@6.1.0-spack arch=linux-centos6-x86_64^cmake@3.5.2%gcc@6.1.0-spack~doc+ncurses+openssl~qt arch=linux-centos6-x86_64^curl@7.49.1%gcc@6.1.0-spack arch=linux-centos6-x86_64^expat@2.1.0%gcc@6.1.0-spack arch=linux-centos6-x86_64^git@2.8.1%gcc@6.1.0-spack arch=linux-centos6-x86_64^hdf5@1.10.0-patch1%gcc@6.1.0-spack+cxx~debug+fortran+mpi+shared~szip~threadsafe arch=linux-centos6-x86_64^hwloc@1.11.3%gcc@6.1.0-spack arch=linux-centos6-x86_64^libpciaccess@0.13.4%gcc@6.1.0-spack arch=linux-centos6-x86_64^libsigsegv@2.10%gcc@6.1.0-spack arch=linux-centos6-x86_64^m4@1.4.17%gcc@6.1.0-spack+sigsegv arch=linux-centos6-x86_64^ncurses@6.0%gcc@6.1.0-spack arch=linux-centos6-x86_64^openmpi@2.0.0%gcc@6.1.0-spack~mxm~pmi~psm~psm2~slurm~sqlite3~thread_multiple~tm+verbs+vt arch=linux-centos6-x86_64^openssl@1.0.2h%gcc@6.1.0-spack arch=linux-centos6-x86_64^python@2.7.11%gcc@6.1.0-spack~ucs4 arch=linux-centos6-x86_64^readline@6.3%gcc@6.1.0-spack arch=linux-centos6-x86_64^sqlite@3.8.5%gcc@6.1.0-spack arch=linux-centos6-x86_64^zlib@1.2.8%gcc@6.1.0-spack arch=linux-centos6-x86_64'

# Fixed code
def __exit__(self, exc_type, exc_val, exc_tb):
    """
    Exiting from a stage context will delete the stage directory unless:
    - it was explicitly requested not to do so
    - an exception has been raised

    Args:
        exc_type: exception type
        exc_val: exception value
        exc_tb: exception traceback

    Returns:
        Boolean
    """
    # Delete when there are no exceptions, unless asked to keep.
    if exc_type is None and not self.keep:
        self.destroy()

    if self._lock is not None:
        self._lock.release_write()