Extension modules: m_traverse, m_clear and m_free functions of
PyModuleDef are no longer called if the module state was requested
but is not allocated yet. This is the case immediately after the
module is created and before the module is executed (Py_mod_exec
function). More precisely, these functions are not called if m_size is
greater than 0 and the module state (as returned by
PyModule_GetState()) is NULL.
Extension modules without module state (m_size <= 0) are not affected.
Co-Authored-By: Petr Viktorin <encukou@gmail.com>
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.
Fix Modules/_testmultiphase.c so that it exits with non-zero status on AIX just as other systems do (non zero exit status, e.g. as result of a segmentation fault) when a NULL pointer is accessed for data.
https://bugs.python.org/issue34720
Multi-phase initialized modules allow m_traverse to be called while the
module is still being initialized, so module authors may need to account
for that.
Multi-phase extension module import now correctly allows the
``m_methods`` field to be used to add module level functions
to instances of non-module types returned from ``Py_create_mod``.
Patch by Xiang Zhang.
To resolve a compatibility problem found with py2exe and
pywin32, imp.load_dynamic() once again ignores previously loaded modules
to support Python modules replacing themselves with extension modules.
Patch by Petr Viktorin.
_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)
- missing DECREF in PyModule_FromDefAndSpec2
- missing DECREF in PyType_FromSpecAndBases2
- missing DECREF in _testmultiphase module
Patch by Petr Viktorin
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
Antoine Pitrou
Serhiy Storchaka
Michael Felt
Benjamin Peterson
Marcel Plch
Nick Coghlan