_PyWeakref_ClearRef was previouslyexposed in the public C-API. In 3.13, it was moved topycore_weakref.h and the symbol is not exposed (i.e., it'sextern void instead ofPyAPI_FUNC(void).

_PyWeakref_ClearRef is used to clear a single weakref without calling its callback._PyWeakref_ClearWeakRefsExceptCallbacks is the thread-safe version. If people are using_PyWeakref_ClearRef, we'd rather they use_PyWeakref_ClearWeakRefsExceptCallbacks so that the code is thread-safe in the free-threading build.

One use case is to clear newly added weakrefs after you've called a finalizer, in case your C type does not delegate to subtype_dealloc.

Uses:

• PyTorch
• shiboken2 (might be old)
• Nuitka

At a minimum, we should addPyAPI_FUNC to_PyWeakref_ClearRef and_PyWeakref_ClearWeakRefsExceptCallbacks and consider making_PyWeakref_ClearWeakRefsExceptCallbacks part of the public C API.

Linked PRs

• gh-118789: Restore hidden_PyWeakref_ClearRef #118797
• gh-118789: AddPyUnstable_Object_ClearWeakRefsNoCallbacks #118807
• [3.13] gh-118789: Restore hidden_PyWeakref_ClearRef (GH-118797) #118903
• [3.13] gh-118789: AddPyUnstable_Object_ClearWeakRefsNoCallbacks (GH-118807) #120695