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@colesbury colesbury commented Dec 16, 2024

The PyWeakref_IsDead() function tests if a weak reference is dead without any side effects. Although you can also detect if a weak reference is dead using PyWeakref_GetRef(), that function returns a strong reference that must be Py_DECREF()'d, which can introduce side effects if the last reference is concurrently dropped.


📚 Documentation preview 📚: https://cpython-previews--128009.org.readthedocs.build/en/128009/c-api/weakref.html#c.PyWeakref_IsDead

The `PyWeakref_IsDead()` function tests if a weak reference is dead
without any side effects. Although you can also detect if a weak
reference is dead using `PyWeakref_GetRef()`, that function returns a
strong reference that must be `Py_DECREF()`'d, which can introduce side
effects if the last reference is concurrently dropped (at least in the
free threading build).
@colesbury colesbury marked this pull request as ready for review December 17, 2024 15:11
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You just need to add the function to What's New in Python 3.14 > C API > New features: https://docs.python.org/dev/whatsnew/3.14.html#id6

@encukou encukou merged commit 7b811d0 into python:main Dec 19, 2024
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@colesbury colesbury deleted the gh-128008-weakref-isdead branch December 19, 2024 15:20
srinivasreddy pushed a commit to srinivasreddy/cpython that referenced this pull request Dec 23, 2024
The `PyWeakref_IsDead()` function tests if a weak reference is dead
without any side effects. Although you can also detect if a weak
reference is dead using `PyWeakref_GetRef()`, that function returns a
strong reference that must be `Py_DECREF()`'d, which can introduce side
effects if the last reference is concurrently dropped (at least in the
free threading build).
srinivasreddy pushed a commit to srinivasreddy/cpython that referenced this pull request Jan 8, 2025
The `PyWeakref_IsDead()` function tests if a weak reference is dead
without any side effects. Although you can also detect if a weak
reference is dead using `PyWeakref_GetRef()`, that function returns a
strong reference that must be `Py_DECREF()`'d, which can introduce side
effects if the last reference is concurrently dropped (at least in the
free threading build).
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4 participants