of PyObject_HasAttr(); the former promises never to execute
arbitrary Python code. Undid many of the changes recently made to
worm around the worst consequences of that PyObject_HasAttr() could
execute arbitrary Python code.
Compatibility is hard to discuss, because the dangerous cases are
so perverse, and much of this appears to rely on implementation
accidents.
To start with, using hasattr() to check for __del__ wasn't only
dangerous, in some cases it was wrong: if an instance of an old-
style class didn't have "__del__" in its instance dict or in any
base class dict, but a getattr hook said __del__ existed, then
hasattr() said "yes, this object has a __del__". But
instance_dealloc() ignores the possibility of getattr hooks when
looking for a __del__, so while object.__del__ succeeds, no
__del__ method is called when the object is deleted. gc was
therefore incorrect in believing that the object had a finalizer.
The new method doesn't suffer that problem (like instance_dealloc(),
_PyObject_Lookup() doesn't believe __del__ exists in that case), but
does suffer a somewhat opposite-- and even more obscure --oddity:
if an instance of an old-style class doesn't have "__del__" in its
instance dict, and a base class does have "__del__" in its dict,
and the first base class with a "__del__" associates it with a
descriptor (an object with a __get__ method), *and* if that
descriptor raises an exception when __get__ is called, then
(a) the current method believes the instance does have a __del__,
but (b) hasattr() does not believe the instance has a __del__.
While these disagree, I believe the new method is "more correct":
because the descriptor *will* be called when the object is
destructed, it can execute arbitrary Python code at the time the
object is destructed, and that's really what gc means by "has a
finalizer": not specifically a __del__ method, but more generally
the possibility of executing arbitrary Python code at object
destruction time. Code in a descriptor's __get__() executed at
destruction time can be just as problematic as code in a
__del__() executed then.
So I believe the new method is better on all counts.
Bugfix candidate, but it's unclear to me how all this differs in
the 2.2 branch (e.g., new-style and old-style classes already
took different gc paths in 2.3 before this last round of patches,
but don't in the 2.2 branch).
platforms which have dup(2). The makefile() method is built directly on top
of the socket without duplicating the file descriptor, allowing timeouts to
work properly. Includes a new test case (urllibnet) which requires the
network resource.
Closes bug 707074.
pack_float, pack_double, save_float: All the routines for creating
IEEE-format packed representations of floats and doubles simply ignored
that rounding can (in rare cases) propagate out of a long string of
1 bits. At worst, the end-off carry can (by mistake) interfere with
the exponent value, and then unpacking yields a result wrong by a factor
of 2. In less severe cases, it can end up losing more low-order bits
than intended, or fail to catch overflow *caused* by rounding.
Bugfix candidate, but I already backported this to 2.2.
In 2.3, this code remains in severe need of refactoring.
variables to store internal data. As a result, any atempts to use the
unicode system with multiple active interpreters, or successive
interpreter executions, would fail.
Now that information is stored into members of the PyInterpreterState
structure.
- Implement the behavior as specified in PEP 277, meaning os.listdir()
will only return unicode strings if it is _called_ with a unicode
argument.
- And then return only unicode, don't attempt to convert to ASCII.
- Don't switch on Py_FileSystemDefaultEncoding, but simply use the
default encoding if Py_FileSystemDefaultEncoding is NULL. This means
os.listdir() can now raise UnicodeDecodeError if the default encoding
can't represent the directory entry. (This seems better than silcencing
the error and fall back to a byte string.)
- Attempted to decribe the above in Doc/lib/libos.tex.
- Reworded the Misc/NEWS items to reflect the current situation.
This checkin also fixes bug #696261, which was due to os.listdir() not
using Py_FileSystemDefaultEncoding, like all file system calls are
supposed to.
[ 555817 ] Flawed fcntl.ioctl implementation.
with my patch that allows for an array to be mutated when passed
as the buffer argument to ioctl() (details complicated by
backwards compatibility considerations -- read the docs!).
Allow mixed-type __eq__ and __ne__ for Set objects. This is messier than
I'd like because Set *also* implements __cmp__. I know of one glitch now:
cmp(s, t) returns 0 now when s and t are both Sets and s == t, despite
that Set.__cmp__ unconditionally raises TypeError (and by intent). The
rub is that __eq__ gets tried first, and the x.__eq__(y) True result
convinces Python that cmp(x, y) is 0 without even calling Set.__cmp__.
rarely needed, but can sometimes be useful to release objects
referenced by the traceback held in sys.exc_info()[2]. (SF patch
#693195.) Thanks to Kevin Jacobs!
Guido van Rossum
Tim Peters
Raymond Hettinger
Martin v. Löwis
Walter Dörwald
Jack Jansen
Skip Montanaro
Gustavo Niemeyer
Michael W. Hudson
Neal Norwitz
Just van Rossum
Andrew M. Kuchling
David Goodger