Merge p3yk branch with the trunk up to revision 45595. This breaks a fair

number of tests, all because of the codecs/_multibytecodecs issue described
here (it's not a Py3K issue, just something Py3K discovers):
http://mail.python.org/pipermail/python-dev/2006-April/064051.html

Hye-Shik Chang promised to look for a fix, so no need to fix it here. The
tests that are expected to break are:

test_codecencodings_cn
test_codecencodings_hk
test_codecencodings_jp
test_codecencodings_kr
test_codecencodings_tw
test_codecs
test_multibytecodec

This merge fixes an actual test failure (test_weakref) in this branch,
though, so I believe merging is the right thing to do anyway.

Lib/contextlib.py

@@ -30,9 +30,22 @@ class GeneratorContextManager(object):
         else:
             try:
                 self.gen.throw(type, value, traceback)
-                return True
-            except StopIteration:
-                return True
+                raise RuntimeError("generator didn't stop after throw()")
+            except StopIteration, exc:
+                # Suppress the exception *unless* it's the same exception that
+                # was passed to throw().  This prevents a StopIteration
+                # raised inside the "with" statement from being suppressed
+                return exc is not value
+            except:
+                # only re-raise if it's *not* the exception that was
+                # passed to throw(), because __exit__() must not raise
+                # an exception unless __exit__() itself failed.  But throw()
+                # has to raise the exception to signal propagation, so this
+                # fixes the impedance mismatch between the throw() protocol
+                # and the __exit__() protocol.
+                #
+                if sys.exc_info()[1] is not value:
+                    raise
 
 
 def contextmanager(func):
@@ -68,6 +81,7 @@ def contextmanager(func):
     try:
         helper.__name__ = func.__name__
         helper.__doc__ = func.__doc__
+        helper.__dict__ = func.__dict__
     except:
         pass
     return helper