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gh-103082: Fix shifted field initialization in`instrumentation.c`#103561

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Merged

markshannon merged 1 commit intopython:mainfromarhadthedev:fix-instrumentation-disable-missing

Apr 21, 2023

Merged

gh-103082: Fix shifted field initialization in`instrumentation.c`#103561

markshannon merged 1 commit intopython:mainfromarhadthedev:fix-instrumentation-disable-missing

Apr 21, 2023

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arhadthedev commentedApr 15, 2023•
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IfPy_TRACE_REFS is defined,PyObject initializers without field names like:

cpython/Python/instrumentation.c

Lines 17 to 21 in2b6f5c3

	staticPyObjectDISABLE=
	{
	_PyObject_IMMORTAL_REFCNT,
	&PyBaseObject_Type
	};

are compiled in a totally unusable way:

_ob_next = _PyObject_IMMORTAL_REFCNT (999999999)_ob_prev = &PyBaseObject_Typeob_refcnt = 0ob_type = NULL

The reason is implicit insertion of two extra fields under#ifdef Py_TRACE_REFS:

cpython/Include/object.h

Lines 102 to 106 in2b6f5c3

	struct_object {
	_PyObject_HEAD_EXTRA
	Py_ssize_tob_refcnt;
	PyTypeObject*ob_type;
	};

cpython/Include/object.h

Lines 65 to 76 in2b6f5c3

	#ifdefPy_TRACE_REFS
	/* Define pointers to support a doubly-linked list of all live heap objects. */
	#define_PyObject_HEAD_EXTRA \
	PyObject *_ob_next; \
	PyObject *_ob_prev;

	#define_PyObject_EXTRA_INIT _Py_NULL, _Py_NULL,

	#else
	# define_PyObject_HEAD_EXTRA
	# define_PyObject_EXTRA_INIT
	#endif

~~This commit fixes declarations that fail theAMD64 Arch Linux TraceRefs PR buildbot. Other declarations will be fixed in another, pending PR.~~ (edit: all other places use_PyObject_HEAD_EXTRA)

I desided to not use_PyObject_HEAD_EXTRA because it can be forgotten easily (unlike explicit field names) so we should phase it out from CPython codebase if possible.

Issue:Implement and document PEP 669. #103082

Fix shifted field initialization in instrumentation.c

286fdc9

arhadthedev added interpreter-core

(Objects, Python, Grammar, and Parser dirs)

type-crash

A hard crash of the interpreter, possibly with a core dump

needs backport to 3.11only security fixes labels

Apr 15, 2023

bedevere-bot added the awaiting review label

Apr 15, 2023

arhadthedev added the 🔨 test-with-buildbotsTest PR w/ buildbots; report in status section label

Apr 15, 2023

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bedevere-bot commentedApr 15, 2023

🤖 New build scheduled with the buildbot fleet by@arhadthedev for commit286fdc9 🤖

If you want to schedule another build, you need to add the🔨 test-with-buildbots label again.

bedevere-bot removed the 🔨 test-with-buildbotsTest PR w/ buildbots; report in status section label

Apr 15, 2023

arhadthedev added 3.12only security fixes and removed needs backport to 3.11only security fixes labels

Apr 15, 2023

arhadthedev changed the title~~Fix shifted field initialization ininstrumentation.c~~gh-103082: Fix shifted field initialization ininstrumentation.c

Apr 15, 2023

bedevere-bot mentioned this pull request

Apr 15, 2023

Implement and document PEP 669.#103082

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arhadthedev added the skip news label

Apr 15, 2023

arhadthedev requested a review frommarkshannon

April 15, 2023 13:32

arhadthedev marked this pull request as ready for review

April 15, 2023 13:32