Allowing 'os.devnull' in Sandbox, fixes #101

--HG--
branch : distribute
extra : rebase_source : d6f63794621874eb637139f353314256e02e02df

CHANGES.txt

@@ -19,6 +19,7 @@ CHANGES
   "setup.cfg" if any exists in the working directory. It will use it
   only if triggered by ``install_requires`` from a setup.py call
   (install, develop, etc).
+* Issue 101: Allowing ``os.devnull`` in Sandbox
 
 -----
 0.6.8

setuptools/sandbox.py

@@ -152,6 +152,8 @@ class AbstractSandbox:
         )
 
 
+_EXCEPTIONS = [os.devnull,]
+
 class DirectorySandbox(AbstractSandbox):
     """Restrict operations to a single subdirectory - pseudo-chroot"""
 
@@ -160,9 +162,10 @@ class DirectorySandbox(AbstractSandbox):
         "utime", "lchown", "chroot", "mkfifo", "mknod", "tempnam",
     ])
 
-    def __init__(self,sandbox):
+    def __init__(self, sandbox, exceptions=_EXCEPTIONS):
         self._sandbox = os.path.normcase(os.path.realpath(sandbox))
         self._prefix = os.path.join(self._sandbox,'')
+        self._exceptions = exceptions
         AbstractSandbox.__init__(self)
 
     def _violation(self, operation, *args, **kw):
@@ -187,7 +190,8 @@ class DirectorySandbox(AbstractSandbox):
         try:
             self._active = False
             realpath = os.path.normcase(os.path.realpath(path))
-            if realpath==self._sandbox or realpath.startswith(self._prefix):
+            if (realpath in self._exceptions or realpath == self._sandbox
+                or realpath.startswith(self._prefix)):
                 return True
         finally:
             self._active = active

setuptools/tests/test_sandbox.py

+"""develop tests
+"""
+import sys
+import os
+import shutil
+import unittest
+import tempfile
+
+from setuptools.sandbox import DirectorySandbox
+
+class TestSandbox(unittest.TestCase):
+
+    def setUp(self):
+        self.dir = tempfile.mkdtemp()
+
+    def tearDown(self):
+        shutil.rmtree(self.dir)
+
+    def test_devnull(self):
+        sandbox = DirectorySandbox(self.dir)
+
+        def _write():
+            f = open(os.devnull, 'w')
+            f.write('xxx')
+            f.close()
+
+        sandbox.run(_write)
+