Starting to support pypy3.11, need guidance for a cfg stanza

[mattip]

Over at a binary build repo I am trying out PyPy3.11 (PyPy with python3.11) on a branch off my fork of PyO3. I changed the C interface for PyObject_DelAttr to be more like CPython3.11: it is a macro that uses PyObject_SetAttr. How can I express that in this cfg stanza? Do I need to define PyPy_3_11 somewhere?

pyo3/pyo3-ffi/src/abstract_.rs

Lines 12 to 15 in 6ec499b

	#[cfg(all(not(Py_3_13), not(PyPy)))] // CPython exposed as a function in 3.13, in object.h
	pub unsafe fn PyObject_DelAttr(o: *mut PyObject, attr_name: *mut PyObject) -> c_int {
	PyObject_SetAttr(o, attr_name, std::ptr::null_mut())
	}

[davidhewitt]

We define our cfgs so that Py_3_11 will be set for Python versions 3.11 and up, which will include PyPy if we detect that version.

So to get "compiling for PyPy with at least a 3.11 interpreter", you can use cfg(all(PyPy, Py_3_11)).

So for this full clause, you'd want to change it to something like

#[cfg(
    all(
        not(Py_3_13), // CPython exposed as a function in 3.13, in object.h 
        not(all(PyPy, not(Py_3_11))) // PyPy exposed as a function until PyPy 3.10, used macro in 3.11+
    )
)]
pub unsafe fn PyObject_DelAttr(o: *mut PyObject, attr_name: *mut PyObject) -> c_int { 
    PyObject_SetAttr(o, attr_name, std::ptr::null_mut()) 
} 

... amusing that CPython went the other direction in 3.13. I guess eventually when PyPy supports 3.13 you'll do similar and revert to the existing function form, to keep in sync with CPython?

[davidhewitt]

It might also be easier to reason about if you swap some all for any and invert the nots, as per usual boolean logic rules. Not sure in this case, looks like it'll be complex either way. The extern symbol in object.rs will need the inverted clause (probably just wrap whatever you settle on in an enclosing not()).

[mattip]

We define our cfgs so that Py_3_11 will be set for Python versions 3.11 and up, which will include PyPy if we detect that version.

Great, and thanks for the other hints.