PEP 285. Everything described in the PEP is here, and there is even
some documentation. I had to fix 12 unit tests; all but one of these
were printing Boolean outcomes that changed from 0/1 to False/True.
(The exception is test_unicode.py, which did a type(x) == type(y)
style comparison. I could've fixed that with a single line using
issubtype(x, type(y)), but instead chose to be explicit about those
places where a bool is expected.
Still to do: perhaps more documentation; change standard library
modules to return False/True from predicates.
The proper fix is not quite what was submitted; it's really better to
take the class of the object passed rather than calling PyMethod_New
with NULL pointer args, because that can then cause other core dumps
later.
I also added a testcase for the fix to classmethods() in test_descr.py.
I've already applied this to the 2.2 branch.
As promised in my response to the bug report, I'm not really fixing
it; in fact, one could argule over what the proper fix should do.
Instead, I'm adding a little magic that raises TypeError if you try to
pickle an instance of a class that has __slots__ but doesn't define or
override __getstate__. This is done by adding a bozo __getstate__
that always raises TypeError.
Bugfix candidate (also the checkin to typeobject.c, of course).
Adapter from SF patch 528038; fixes SF bug 527816.
The wrapper for __nonzero__ should be wrap_inquiry rather than
wrap_unaryfunc, since the slot returns an int, not a PyObject *.
Due to the bizarre definition of _PyLong_Copy(), creating an instance
of a subclass of long with a negative value could cause core dumps
later on. Unfortunately it looks like the behavior of _PyLong_Copy()
is quite intentional, so the fix is more work than feels comfortable.
This fix is almost, but not quite, the code that Naofumi Honda added;
in addition, I added a test case.
deepcopy(), _reconstruct(): pass the memo to the other function, so
that recursive data structures built out of new-style objects may be
deeply copied correctly.
2.2.1 bugfix!
Fix for SF bug #492345. (I could've sworn I checked this in, but
apparently I didn't!)
This code:
class Classic:
pass
class New(Classic):
__metaclass__ = type
attempts to create a new-style class with only classic bases -- but it
doesn't work right. Attempts to fix it so it works caused problems
elsewhere, so I'm now raising a TypeError in this case.
Big Hammer to implement -Qnew as PEP 238 says it should work (a global
option affecting all instances of "/").
pydebug.h, main.c, pythonrun.c: define a private _Py_QnewFlag flag, true
iff -Qnew is passed on the command line. This should go away (as the
comments say) when true division becomes The Rule. This is
deliberately not exposed to runtime inspection or modification: it's
a one-way one-shot switch to pretend you're using Python 3.
ceval.c: when _Py_QnewFlag is set, treat BINARY_DIVIDE as
BINARY_TRUE_DIVIDE.
test_{descr, generators, zipfile}.py: fiddle so these pass under
-Qnew too. This was just a matter of s!/!//! in test_generators and
test_zipfile. test_descr was trickier, as testbinop() is passed
assumptions that "/" is the same as calling a "__div__" method; put
a temporary hack there to call "__truediv__" instead when the method
name is "__div__" and 1/2 evaluates to 0.5.
Three standard tests still fail under -Qnew (on Windows; somebody
please try the Linux tests with -Qnew too! Linux runs a whole bunch
of tests Windows doesn't):
test_augassign
test_class
test_coercion
I can't stay awake longer to stare at this (be my guest). Offhand
cures weren't obvious, nor was it even obvious that cures are possible
without major hackery.
Question: when -Qnew is in effect, should calls to __div__ magically
change into calls to __truediv__? See "major hackery" at tail end of
last paragraph <wink>.
It was easier than I thought, assuming that no other things contribute
to the instance size besides slots -- a pretty good bet. With a test
suite, no less!
happy if one could delete the __dict__ attribute of an instance. I
love to make Jim happy, so here goes...
- New-style objects now support deleting their __dict__. This is for
all intents and purposes equivalent to assigning a brand new empty
dictionary, but saves space if the object is not used further.
There's now a new structmember code, T_OBJECT_EX, which is used for
all __slot__ variables (except __weakref__, which has special behavior
anyway). This new code raises AttributeError when the variable is
NULL rather than converting NULL to None.
Rather than tweaking the inheritance of type object slots (which turns
out to be too messy to try), this fix adds a __hash__ to the list and
dict types (the only mutable types I'm aware of) that explicitly
raises an error. This has the advantage that list.__hash__([]) also
raises an error (previously, this would invoke object.__hash__([]),
returning the argument's address); ditto for dict.__hash__.
The disadvantage for this fix is that 3rd party mutable types aren't
automatically fixed. This should be added to the rules for creating
subclassable extension types: if you don't want your object to be
hashable, add a tp_hash function that raises an exception.
Also, it's possible that I've forgotten about other mutable types for
which this should be done.
SF patch #480716 by Greg Chapman fixes the problem that super's
__get__ method always returns an instance of super, even when the
instance whose __get__ method is called is an instance of a subclass
of super.
Other issues fixed:
- super(C, C()).__class__ would return the __class__ attribute of C()
rather than the __class__ attribute of the super object. This is
confusing. To fix this, I decided to change the semantics of super
so that it only applies to code attributes, not to data attributes.
After all, overriding data attributes is not supported anyway.
- While super(C, x) carefully checked that x is an instance of C,
super(C).__get__(x) made no such check, allowing for a loophole.
This is now fixed.
of multiple inheritance from a mix of new- and classic-style classes.
This is his patch, plus a start at some test cases from me. Will check
in more, plus a NEWS blurb, later tonight.
outer level, the iterator protocol is used for memory-efficiency (the
outer sequence may be very large if fully materialized); at the inner
level, PySequence_Fast() is used for time-efficiency (these should
always be sequences of length 2).
dictobject.c, new functions PyDict_{Merge,Update}FromSeq2. These are
wholly analogous to PyDict_{Merge,Update}, but process a sequence-of-2-
sequences argument instead of a mapping object. For now, I left these
functions file static, so no corresponding doc changes. It's tempting
to change dict.update() to allow a sequence-of-2-seqs argument too.
Also changed the name of dictionary's keyword argument from "mapping"
to "x". Got a better name? "mapping_or_sequence_of_pairs" isn't
attractive, although more so than "mosop" <wink>.
abstract.h, abstract.tex: Added new PySequence_Fast_GET_SIZE function,
much faster than going thru the all-purpose PySequence_Size.
libfuncs.tex:
- Document dictionary().
- Fiddle tuple() and list() to admit that their argument is optional.
- The long-winded repetitions of "a sequence, a container that supports
iteration, or an iterator object" is getting to be a PITA. Many
months ago I suggested factoring this out into "iterable object",
where the definition of that could include being explicit about
generators too (as is, I'm not sure a reader outside of PythonLabs
could guess that "an iterator object" includes a generator call).
- Please check my curly braces -- I'm going blind <0.9 wink>.
abstract.c, PySequence_Tuple(): When PyObject_GetIter() fails, leave
its error msg alone now (the msg it produces has improved since
PySequence_Tuple was generalized to accept iterable objects, and
PySequence_Tuple was also stomping on the msg in cases it shouldn't
have even before PyObject_GetIter grew a better msg).
used by the weakref code since he didn't like the word "referencable".
Is it really necessary to be more specific than to test for TypeError here,
though?
object.c, PyObject_Str: Don't try to optimize anything except exact
string objects here; in particular, let str subclasses go thru tp_str,
same as non-str objects. This allows overrides of tp_str to take
effect.
stringobject.c:
+ string_print (str's tp_print): If the argument isn't an exact string
object, get one from PyObject_Str.
+ string_str (str's tp_str): Make a genuine-string copy of the object if
it's of a proper str subclass type. str() applied to a str subclass
that doesn't override __str__ ends up here.
test_descr.py: New str_of_str_subclass() test.
inherit_slots(): tp_as_buffer was getting inherited as if it were a
method pointer, rather than a pointer to a vector of method pointers. As
a result, inheriting from a type that implemented buffer methods was
ineffective, leaving all the tp_as_buffer slots NULL in the subclass.
corresponding to a dispatch slot (e.g. __getitem__ or __add__) is set,
calculate the proper dispatch slot and propagate the change to all
subclasses. Because of multiple inheritance, there's no easy way to
avoid always recursing down the tree of subclasses. Who cares?
(There's more to do, but this works. There's also a test for this now.)
without the Py_TPFLAGS_CHECKTYPES flag) in the wrappers. This
required a few changes in test_descr.py to cope with the fact that the
complex type has __int__, __long__ and __float__ methods that always
raise an exception.
this type of test fails, vereq() does a better job of reporting than
verify().
Change vereq(x, y) to use "not x == y" rather than "x != y" -- it
makes a difference is some overloading tests.
For a dynamically constructed type object, fill in the tp_doc slot with
a copy of the argument dict's "__doc__" value, provided the latter exists
and is a string.
NOTE: I don't know what to do if it's a Unicode string, so in that case
tp_doc is left NULL (which shows up as Py_None if you do Class.__doc__).
Note that tp_doc holds a char*, not a general PyObject*.
test for modifying __getattr__ works, now that slot_tp_getattr_hook
zaps the slot if there's no hook. Added an XXX comment with a ref
back to slot_tp_getattr_hook.
- The test for deepcopy() in pickles() was indented wrongly, so it got
run twice (one for binary pickle mode, one for text pickle mode; but
the test doesn't depend on the pickle mode).
- In verbose mode, show which subtest (pickle/cPickle/deepcopy, text/bin).
staticness when __dynamic__ = 1 becomes the default:
- Some classes which are used to test the difference between static
and dynamic.
- Subclasses of complex: complex uses old-style numbers and the slot
wrappers used by dynamic classes only support new-style numbers.
(Ideally, the complex type should be fixed, but that looks like a
labor-intensive job.)
Guido van Rossum
Neal Norwitz
Fred Drake
Walter Dörwald
Tim Peters