Use new form of with-statement instead of contextlib.nested().

Lib/filecmp.py

@@ -11,7 +11,6 @@ Functions:
 
 import os
 import stat
-import contextlib
 from itertools import filterfalse
 
 __all__ = ["cmp", "dircmp", "cmpfiles"]
@@ -63,7 +62,7 @@ def _sig(st):
 
 def _do_cmp(f1, f2):
     bufsize = BUFSIZE
-    with contextlib.nested(open(f1, 'rb'), open(f2, 'rb')) as (fp1, fp2):
+    with open(f1, 'rb') as fp1, open(f2, 'rb') as fp2:
         while True:
             b1 = fp1.read(bufsize)
             b2 = fp2.read(bufsize)

Lib/test/support.py

@@ -591,13 +591,11 @@ class TransientResource(object):
                 raise ResourceDenied("an optional resource is not available")
 
 
-def transient_internet():
+# Context managers that raise ResourceDenied when various issues
-    """Return a context manager that raises ResourceDenied when various issues
+# with the Internet connection manifest themselves as exceptions.
-    with the Internet connection manifest themselves as exceptions."""
+time_out = TransientResource(IOError, errno=errno.ETIMEDOUT)
-    time_out = TransientResource(IOError, errno=errno.ETIMEDOUT)
+socket_peer_reset = TransientResource(socket.error, errno=errno.ECONNRESET)
-    socket_peer_reset = TransientResource(socket.error, errno=errno.ECONNRESET)
+ioerror_peer_reset = TransientResource(IOError, errno=errno.ECONNRESET)
-    ioerror_peer_reset = TransientResource(IOError, errno=errno.ECONNRESET)
-    return contextlib.nested(time_out, socket_peer_reset, ioerror_peer_reset)
 
 
 @contextlib.contextmanager

Lib/test/test_signal.py

@@ -146,8 +146,8 @@ class InterProcessSignalTests(unittest.TestCase):
         # re-raises information about any exceptions the child
         # throws. The real work happens in self.run_test().
         os_done_r, os_done_w = os.pipe()
-        with nested(closing(os.fdopen(os_done_r, 'rb')),
+        with closing(os.fdopen(os_done_r, 'rb')) as done_r, \
-                    closing(os.fdopen(os_done_w, 'wb'))) as (done_r, done_w):
+             closing(os.fdopen(os_done_w, 'wb')) as done_w:
             child = os.fork()
             if child == 0:
                 # In the child process; run the test and report results

Lib/test/test_urllib2net.py

@@ -174,7 +174,9 @@ class OtherNetworkTests(unittest.TestCase):
                            (expected_err, url, req, type(err), err))
                     self.assert_(isinstance(err, expected_err), msg)
             else:
-                with support.transient_internet():
+                with support.time_out, \
+                     support.socket_peer_reset, \
+                     support.ioerror_peer_reset:
                     buf = f.read()
                 f.close()
                 debug("read %d bytes" % len(buf))