discovered that subtype_traverse must traverse the type if it is a
heap type, because otherwise some cycles involving a type and its
instance would not be collected. Simplest example:
while 1:
class C(object): pass
C.ref = C()
This program grows without bounds before this fix. (It grows ever
slower since it spends ever more time in the collector.)
Simply adding the right visit() call to subtype_traverse() revealed
other problems. With MvL's help we re-learned that type_clear()
doesn't have to clear *all* references, only the ones that may not be
cleared by other means. Careful analysis (see comments in the code)
revealed that only tp_mro needs to be cleared. (The previous checkin
to this file adds a test for tp_mro==NULL to _PyType_Lookup() that's
essential to prevent crashes due to tp_mro being NULL when
subtype_dealloc() tries to look for a __del__ method.) The same kind
of analysis also revealed that subtype_clear() doesn't need to clear
the instance dict.
With this fix, a useful property of the collector is once again
guaranteed: a single gc.collect() call will clear out all garbage.
(It didn't always before, which put us on the track of this bug.)
Will backport to 2.2.
about the test case, slot_nb_power gets called on behalf of its second
argument, but with a non-None modulus it wouldn't check this, and
believes it is called on behalf of its first argument. Fix this
properly, and get rid of the code in _PyType_Lookup() that tries to
call _PyType_Ready(). But do leave a check for a NULL tp_mro there,
because this can still legitimately occur.
I'll fix this in 2.2.x too.
While I was at it, I added a tp_clear handler and changed the
tp_dealloc handler to use the clear_slots helper for the tp_clear
handler.
Also tightened the rules for slot names: they must now be proper
identifiers (ignoring the dirty little fact that <ctype.h> is locale
sensitive).
Also set mp->flags = READONLY for the __weakref__ pseudo-slot.
Most of this is a 2.2 bugfix candidate; I'll apply it there myself.
Change the module constructor (module_init) to have the signature
__init__(name:str, doc=None); this prevents the call from type_new()
to succeed. While we're at it, prevent repeated calling of
module_init for the same module from leaking the dict, changing the
semantics so that __dict__ is only initialized if NULL.
Also adding a unittest, test_module.py.
This is an incompatibility with 2.2, if anybody was instantiating the
module class before, their argument list was probably empty; so this
can't be backported to 2.2.x.
In the past, an object's tp_compare could return any value. In 2.2
the docs were tightened to require it to return -1, 0 or 1; and -1 for
an error.
We now issue a warning if the value is not in this range. When an
exception is raised, we allow -1 or -2 as return value, since -2 will
the recommended return value for errors in the future. (Eventually
tp_compare will also be allowed to return +2, to indicate
NotImplemented; but that can only be implemented once we know all
extensions return a value in [-2...1]. Or perhaps it will require the
type to set a flag bit.)
I haven't decided yet whether to backport this to 2.2.x. The patch
applies fine. But is it fair to start warning in 2.2.2 about code
that worked flawlessly in 2.2.1?
for 'str' and 'unicode', and can be used instead of
types.StringTypes, e.g. to test whether something is "a string":
isinstance(x, string) is True for Unicode and 8-bit strings. This
is an abstract base class and cannot be instantiated directly.
A MemoryError is now raised when the list cannot be created.
There is a test, but as the comment says, it really only
works for 32 bit systems. I don't know how to improve
the test for other systems (ie, 64 bit or systems
where the data size != addressable size,
e.g. 64 bit data, but 48 bit addressable memory)
returned a proxy for __class__ whose __bases__ was also a proxy. The
merge_class_dict() helper for dir() assumed incorrectly that __bases__
would always be a tuple and used the in-line tuple API on the proxy.
I will backport this to 2.2 as well.
handlers were both set, but were not compatible. This change uses only the
tp_getattro handler with a more "modern" approach.
This fixes SF bug #551285.
don't understand how this function works, also beefed up the docs. The
most common usage error is of this form (often spread out across gotos):
if (_PyString_Resize(&s, n) < 0) {
Py_DECREF(s);
s = NULL;
goto outtahere;
}
The error is that if _PyString_Resize runs out of memory, it automatically
decrefs the input string object s (which also deallocates it, since its
refcount must be 1 upon entry), and sets s to NULL. So if the "if"
branch ever triggers, it's an error to call Py_DECREF(s): s is already
NULL! A correct way to write the above is the simpler (and intended)
if (_PyString_Resize(&s, n) < 0)
goto outtahere;
Bugfix candidate.
This implements ideas from Marc-Andre, Martin, Guido and me on Python-Dev.
"Short" Unicode strings are encoded into a "big enough" stack buffer,
then exactly as much string space as they turn out to need is allocated
at the end. This should have speed benefits akin to Martin's "measure
once, allocate once" strategy, but without needing a distinct measuring
pass.
"Long" Unicode strings allocate as much heap space as they could possibly
need (4 x # Unicode chars), and do a realloc at the end to return the
untouched excess. Since the overallocation is likely to be substantial,
this shouldn't burden the platform realloc with unusably small excess
blocks.
Also simplified uses of the PyString_xyz functions. Also added a release-
build check that 4*size doesn't overflow a C int. Sooner or later, that's
going to happen.
left and right type were of the same type and not classic instances.
This shortcut is dangerous for proxy types, because it means that
coerce(Proxy(1), Proxy(2.1)) leaves Proxy(1) unchanged rather than
turning it into Proxy(1.0).
In an ever-so-slight change of semantics, I now only take the shortcut
when the left and right types are of the same type and don't have the
CHECKTYPES feature. It so happens that classic instances have this
flag, so the shortcut is still skipped in this case (i.e. nothing
changes for classic instances). Proxies also have this flag set
(otherwise implementing numeric operations on proxies would become
nightmarish) and this means that the shortcut is also skipped there,
as desired. It so happens that int, long and float also have this
flag set; that means that e.g. coerce(1, 1) will now invoke
int_coerce(). This is fine: int_coerce() can deal with this, and I'm
not worried about the performance; int_coerce() is only invoked when
the user explicitly calls coerce(), which should be rarer than rare.
This fixes the problem that Barry reported on python-dev:
>>> 23000 .__class__ = bool
crashes in the deallocator. This was because int inherited tp_free
from object, which uses the default allocator.
2.2. Bugfix candidate.
states can be for this function, and ensure that only AttributeErrors
are masked. Any other exception raised via the equivalent of
getattr(cls, '__bases__') should be propagated up.
abstract_issubclass(): If abstract_get_bases() returns NULL, we must
call PyErr_Occurred() to see if an exception is being propagated, and
return -1 or 0 as appropriate. This is the specific fix for a problem
whereby if getattr(derived, '__bases__') raised an exception, an
"undetected error" would occur (under a debug build). This nasty
situation was uncovered when writing a security proxy extension type
for the Zope3 project, where the security proxy raised a Forbidden
exception on getattr of __bases__.
PyObject_IsInstance(), PyObject_IsSubclass(): After both calls to
abstract_get_bases(), where we're setting the TypeError if the return
value is NULL, we must first check to see if an exception occurred,
and /not/ mask an existing exception.
Neil Schemenauer should double check that these changes don't break
his ExtensionClass examples (there aren't any test cases for those
examples and abstract_get_bases() was added by him in response to
problems with ExtensionClass). Neil, please add test cases if
possible!
I belive this is a bug fix candidate for Python 2.2.2.
http://www.python.org/sf/444708
This adds the optional argument for str.strip
to unicode.strip too and makes it possible
to call str.strip with a unicode argument
and unicode.strip with a str argument.
+ Continued looping until n bytes in the buffer have been filled, not
just when n bytes have been read from the file. This repairs the
bug that f.readlines() only sucked up the first 8192 bytes of the file
on Windows when universal newlines was enabled and f was opened in
U mode (see Python-Dev -- this was the ultimate cause of the
test_inspect.py failure).
+ Changed prototye to take a char* buffer (void* doesn't make much sense).
+ Squashed size_t vs int mismatches (in particular, besides the unsigned
vs signed distinction, size_t may be larger than int).
+ Gets out under all error conditions now (it's possible for fread() to
suffer an error even if it returns a number larger than 0 -- any
"short read" is an error or EOF condition).
+ Rearranged and simplified declarations.
pointers is a signed type. Changing "allocated" to a signed int makes
undetected overflow more likely, but there was no overflow detection
before either.
PyFrame_FastToLocals() and PyFrame_LocalsToFast() had a return if
f_nlocals was 0. I think this was a holdover from the pre 2.1 days
when regular locals were the only kind of local variables.
The change makes it possible to use a free variable in eval or exec if
it the variable is also used elsewhere in the same block, which is
what the documentation says.
consistency checks, enabled only in a debug (Py_DEBUG) build. Note that
this never gets called automatically unless PYMALLOC_DEBUG is #define'd
too, and the envar PYTHONMALLOCSTATS exists.
Change type_get_doc (the get function for __doc__) to look in tp_dict
more often, and if it finds a descriptor in tp_dict, to call it (with
a NULL instance). This means you can add a __doc__ descriptor to a
new-style class that returns instance docs when called on an instance,
and class docs when called on a class -- or the same docs in either
case, but lazily computed.
I'll also check this into the 2.2 maintenance branch.
PyNumber_InPlaceMultiply insisted on calling sq_inplace_repeat if it
existed, even if nb_inplace_multiply also existed and the arguments
weren't right for sq_inplace_repeat. Change this to only use
sq_inplace_repeat if nb_inplace_multiply isn't defined.
Bugfix candidate.
Add a method zfill to str, unicode and UserString and change
Lib/string.py accordingly.
This activates the zfill version in unicodeobject.c that was
commented out and implements the same in stringobject.c. It also
adds the test for unicode support in Lib/string.py back in and
uses repr() instead() of str() (as it was before Lib/string.py 1.62)
Complex numbers implement divmod() and //, neither of which makes one
lick of sense. Unfortunately this is documented, so I'm adding a
deprecation warning now, so we can delete this silliness, oh, around
2005 or so.
Bugfix candidate (At least for 2.2.2, I think.)
Highlights: import and friends will understand any of \r, \n and \r\n
as end of line. Python file input will do the same if you use mode 'U'.
Everything can be disabled by configuring with --without-universal-newlines.
See PEP278 for details.
Added code to call this when PYMALLOC_DEBUG is enabled, and envar
PYTHONMALLOCSTATS is set, whenever a new arena is obtained and once
late in the Python shutdown process.
Put a bound on the number of frameobjects that can live in the
frameobject free_list.
Am also backporting to 2.2. I don't intend to backport to 2.1 (too
much work -- lots of cyclic structures leak there, and the GC API).
Add optional arg to string methods strip(), lstrip(), rstrip().
The optional arg specifies characters to delete.
Also for UserString.
Still to do:
- Misc/NEWS
- LaTeX docs (I did the docstrings though)
- Unicode methods, and Unicode support in the string methods.
_PyObject_DebugMalloc: explicitly cast PyObject_Malloc's result to the
target pointer type.
_PyObject_DebugDumpStats: change decl of arena_alignment from unsigned
int to unsigned long.
This is for the 2.3 release only (it's new code).
most of the work. In particular, if the underlying realloc is able to
grow the memory block in place, great (this routine used to do a fresh
malloc + memcpy every time a block grew). BTW, I'm not so keen here on
avoiding possible quadratic-time realloc patterns as I am on making
the debug pymalloc more invisible (the more it uses memory "just like"
the underlying allocator, the better the chance that a suspected memory
corruption bug won't vanish when the debug malloc is turned on).
PyMem_{Del, DEL} doesn't work yet (compilation problems).
pyport.h: _PyMem_EXTRA is gone.
pmem.h: Repaired comments. PyMem_{Malloc, MALLOC} and
PyMem_{Realloc, REALLOC} now make the same x-platform guarantees when
asking for 0 bytes, and when passing a NULL pointer to the latter.
object.c: PyMem_{Malloc, Realloc} just call their macro versions
now, since the latter take care of the x-platform 0 and NULL stuff
by themselves now.
pypcre.c, grow_stack(): So sue me. On two lines, this called
PyMem_RESIZE to grow a "const" area. It's not legit to realloc a
const area, so the compiler warned given the new expansion of
PyMem_RESIZE. It would have gotten the same warning before if it
had used PyMem_Resize() instead; the older macro version, but not the
function version, silently cast away the constness. IMO that was a wrong
thing to do, and the docs say the macro versions of PyMem_xyz are
deprecated anyway. If somebody else is resizing const areas with the
macro spelling, they'll get a warning when they recompile now too.
The bug report pointed out a bogosity in the comment block explaining
thread safety for arena management. Repaired that comment, repaired a
couple others while I was at it, and added an assert.
_PyMalloc_DebugRealloc: If this needed to get more memory, but couldn't,
it erroneously freed the original memory. Repaired that.
This is for 2.3 only (unless we decide to backport the new pymalloc).
open_the_file: Some (not all) flavors of Windows set errno to EINVAL
when passed a syntactically invalid filename. Python turned that into an
incomprehensible complaint about the mode string. Fixed by special-casing
MSVC.
when PyType_Ready() was called, if ob_type was found to be NULL, it
was always set to &PyType_Type; now it is set to base->ob_type,
where base is tp_base, defaulting to &PyObject_Type.
- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
Bugfix candidate.
