def _activate(self):
if not self._working_set:
working_set = WorkingSet([])
# set up the local .pex environment
pex_info = self._pex_info.copy()
pex_info.update(self._pex_info_overrides)
pex_info.merge_pex_path(self._vars.PEX_PATH)
self._envs.append(PEXEnvironment(self._pex, pex_info, interpreter=self._interpreter))
# N.B. by this point, `pex_info.pex_path` will contain a single pex path
# merged from pex_path in `PEX-INFO` and `PEX_PATH` set in the environment.
# `PEX_PATH` entries written into `PEX-INFO` take precedence over those set
# in the environment.
if pex_info.pex_path:
# set up other environments as specified in pex_path
for pex_path in filter(None, pex_info.pex_path.split(os.pathsep)):
pex_info = PexInfo.from_pex(pex_path)
pex_info.update(self._pex_info_overrides)
self._envs.append(
PEXEnvironment(pex_path, pex_info, interpreter=self._interpreter)
)
# activate all of them
for env in self._envs:
for dist in env.activate():
working_set.add(dist)
# Ensure that pkg_resources is not imported until at least every pex environment
# (i.e. PEX_PATH) has been merged into the environment
PEXEnvironment.declare_namespace_packages(working_set)
self._working_set = working_set
return self._working_set
