def preserve_environ():
old = environ.copy()
yield
# don't touch existing values as os.environ is broken for empty
# keys on Windows: http://bugs.python.org/issue20658
for key, value in list(environ.items()):
if key not in old:
del environ[key]
for key, value in old.items():
if key not in environ or environ[key] != value:
environ[key] = value
def preserve_environ():
old = environ.copy()
yield
# don't touch existing values as os.environ is broken for empty
# keys on Windows: http://bugs.python.org/issue20658
for key, value in list(environ.items()):
if key not in old:
del environ[key]
for key, value in old.items():
if key not in environ or environ[key] != value:
environ[key] = value