In the limited C API version 3.11 and newer, the following functions
no longer cast their object pointer argument with _PyObject_CAST() or
_PyObject_CAST_CONST():
* Py_REFCNT(), Py_TYPE(), Py_SIZE()
* Py_SET_REFCNT(), Py_SET_TYPE(), Py_SET_SIZE()
* Py_IS_TYPE()
* Py_INCREF(), Py_DECREF()
* Py_XINCREF(), Py_XDECREF()
* Py_NewRef(), Py_XNewRef()
* PyObject_TypeCheck()
* PyType_Check()
* PyType_CheckExact()
Split Py_DECREF() implementation in 3 versions to make the code more
readable.
Update the xxlimited.c extension, which uses the limited C API
version 3.11, to pass PyObject* to these functions.
The Python 3.11 limited C API no longer includes stdlib.h, stdio.h,
string.h and errno.h.
* Exclude Py_MEMCPY() from Python 3.11 limited C API.
* xxlimited C extension is now built with Python 3.11 limited C API.
xxlimited.c and xxlimited_35.c now define the Py_LIMITED_API macro,
rather than having to do it in the build recipe.
Co-authored-by: Hai Shi <shihai1992@gmail.com>
- Copy existing xxlimited to xxlimited53 (named for the limited API version it uses)
- Build both modules, both in debug and release
- Test both modules
It is now allowed to add new fields at the end of the PyTypeObject struct without having to allocate a dedicated compatibility flag in tp_flags.
This will reduce the risk of running out of bits in the 32-bit tp_flags value.
_testmultiphase and xxlimited now use tp_traverse and
tp_finalize to avoid reference leaks encountered when
combining tp_dealloc with PyType_FromSpec (see
issue #16690 for details)
Known limitations of the current implementation:
- documentation changes are incomplete
- there's a reference leak I haven't tracked down yet
The leak is most visible by running:
./python -m test -R3:3 test_importlib
However, you can also see it by running:
./python -X showrefcount
Importing the array or _testmultiphase modules, and
then deleting them from both sys.modules and the local
namespace shows significant increases in the total
number of active references each cycle. By contrast,
with _testcapi (which continues to use single-phase
initialisation) the global refcounts stabilise after
a couple of cycles.
Victor Stinner
Christian Heimes
Hai Shi
Petr Viktorin
Pablo Galindo
Dong-hee Na
Antoine Pitrou
Serhiy Storchaka
Benjamin Peterson
Nick Coghlan
Martin v. Löwis
Brian Curtin