Use _PyObject_IsUniquelyReferenced instead of `Py_REFCNT(x) == 1` for free-threaded compatibility

[sergey-miryanov]

Feature or enhancement

Proposal:

There are a lot of places where Py_REFCNT(..)==1 used. IIUC it is not correct for no-gil version.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• GH-140061: Use _PyObject_IsUniquelyReferenced to check if object is uniquely referenced #140062