Revert commits:
gh-151593: Fix dead lock in PyDict insert_split_key() (#152200)
gh-150490: Raise PyType_Modified for insertion into split dictionary (#150489)
For gh-150489, it violates locking discipline and results in deadlocks,
gh-151593 is an example of it being hit in CI. The attempted fix
gh-152200 avoids the deadlock but introduces a data-race. The race
window is small but can be triggered with pure Python code.
The initial implementation of PEP 820 worsened the error message
when non-types are given as base types in Py_tp_bases & Py_tp_base.
Bring back the 'bases must be types' wording and add a 'got' note for
easier debugging.
Improve slot ID documentation, and soft-deprecate Py_tp_base
(as per the PEP).
Call PyBuffer_Release() if PyObject_GC_New() fails.
Fix also bytes_join(): only call Py_DECREF(item) after formatting the
error message which uses item.
Replace also _PyObject_HashFast() with PyObject_Hash()
in _collections._count_elements().
Rename _PyObject_HashFast() to _PyObject_HashDictKey(),
and mark it as Py_ALWAYS_INLINE.
Only use _PyObject_HashDictKey() on dictionaries.
There are newly documented restrictions on tp_traverse:
The traversal function must not have any side effects.
It must not modify the reference counts of any Python
objects nor create or destroy any Python objects.
* Add several functions that are guaranteed side-effect-free,
with a _DuringGC suffix.
* Use these in ctypes
* Consolidate tp_traverse docs in gcsupport.rst, moving unique
content from typeobj.rst there
Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
We already have a stop-the-world pause elsewhere in this code path
(type_set_bases) and this makes will make it easier to avoid contention
on the TYPE_LOCK when looking up names in the MRO hierarchy.
Also use deferred reference counting for non-immortal MROs.
Add `_Py_type_getattro_stackref`, a variant of type attribute lookup
that returns `_PyStackRef` instead of `PyObject*`. This allows returning
deferred references in the free-threaded build, reducing reference count
contention when accessing type attributes.
This significantly improves scaling of namedtuple instantiation across
multiple threads.
* Add blurb
* Rename PyObject_GetAttrStackRef to _PyObject_GetAttrStackRef
* Apply suggestion from @vstinner
Co-authored-by: Victor Stinner <vstinner@python.org>
* Apply suggestion from @vstinner
Co-authored-by: Victor Stinner <vstinner@python.org>
* format
* Update Include/internal/pycore_function.h
Co-authored-by: Victor Stinner <vstinner@python.org>
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Co-authored-by: Victor Stinner <vstinner@python.org>
Kumar Aditya