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Issue #5837: Certain sequences of calls to set() and unset() for

Browse source 
support.EnvironmentVarGuard objects restored the environment variables
incorrectly on __exit__.

Fix this by recording the initial value of each environment variable on the
first access in set() or unset().
This commit is contained in:
Walter Dörwald 2009-04-25 12:15:07 +00:00
parent 162641a24c
commit a145317be9
2 changed files with 21 additions and 15 deletions
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32
Lib/test/test_support.py
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@ -532,30 +532,32 @@ class EnvironmentVarGuard(object):
a context manager."""
def __init__(self):
self._environ = os.environ
self._unset = set()
self._reset = dict()
self._changed = {}
def set(self, envvar, value):
if envvar not in self._environ:
self._unset.add(envvar)
else:
self._reset[envvar] = self._environ[envvar]
self._environ[envvar] = value
# Remember the initial value on the first access
if envvar not in self._changed:
self._changed[envvar] = os.environ.get(envvar)
os.environ[envvar] = value
def unset(self, envvar):
if envvar in self._environ:
self._reset[envvar] = self._environ[envvar]
del self._environ[envvar]
# Remember the initial value on the first access
if envvar not in self._changed:
self._changed[envvar] = os.environ.get(envvar)
if envvar in os.environ:
del os.environ[envvar]
def __enter__(self):
return self
def __exit__(self, *ignore_exc):
for envvar, value in self._reset.iteritems():
self._environ[envvar] = value
for unset in self._unset:
del self._environ[unset]
for (k, v) in self._changed.items():
if v is None:
if k in os.environ:
del os.environ[k]
else:
os.environ[k] = v
class TransientResource(object):