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gh-113750: Fix object resurrection in free-threaded builds (gh-113751)
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gh-113750: Fix object resurrection on free-threaded builds

This avoids the undesired re-initializing of fields like `ob_gc_bits`,
`ob_mutex`, and `ob_tid` when an object is resurrected due to its
finalizer being called.

This change has no effect on the default (with GIL) build.
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colesbury authored Jan 6, 2024
1 parent 3375dfe commit d0f0308
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Showing 3 changed files with 14 additions and 6 deletions.
1 change: 1 addition & 0 deletions Include/cpython/object.h
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@

PyAPI_FUNC(void) _Py_NewReference(PyObject *op);
PyAPI_FUNC(void) _Py_NewReferenceNoTotal(PyObject *op);
PyAPI_FUNC(void) _Py_ResurrectReference(PyObject *op);

#ifdef Py_REF_DEBUG
/* These are useful as debugging aids when chasing down refleaks. */
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4 changes: 1 addition & 3 deletions Modules/_testcapi/gc.c
Original file line number Diff line number Diff line change
Expand Up @@ -126,9 +126,7 @@ slot_tp_del(PyObject *self)
* never happened.
*/
{
Py_ssize_t refcnt = Py_REFCNT(self);
_Py_NewReferenceNoTotal(self);
Py_SET_REFCNT(self, refcnt);
_Py_ResurrectReference(self);
}
assert(!PyType_IS_GC(Py_TYPE(self)) || PyObject_GC_IsTracked(self));
}
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15 changes: 12 additions & 3 deletions Objects/object.c
Original file line number Diff line number Diff line change
Expand Up @@ -509,9 +509,7 @@ PyObject_CallFinalizerFromDealloc(PyObject *self)

/* tp_finalize resurrected it! Make it look like the original Py_DECREF
* never happened. */
Py_ssize_t refcnt = Py_REFCNT(self);
_Py_NewReferenceNoTotal(self);
Py_SET_REFCNT(self, refcnt);
_Py_ResurrectReference(self);

_PyObject_ASSERT(self,
(!_PyType_IS_GC(Py_TYPE(self))
Expand Down Expand Up @@ -2389,6 +2387,17 @@ _Py_NewReferenceNoTotal(PyObject *op)
new_reference(op);
}

void
_Py_ResurrectReference(PyObject *op)
{
if (_PyRuntime.tracemalloc.config.tracing) {
_PyTraceMalloc_NewReference(op);
}
#ifdef Py_TRACE_REFS
_Py_AddToAllObjects(op);
#endif
}


#ifdef Py_TRACE_REFS
void
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