Opaque PyObject ABI support

Cargo.toml

@@ -116,7 +116,8 @@ abi3-py310 = ["abi3-py311", "pyo3-build-config/abi3-py310", "pyo3-ffi/abi3-py310
 abi3-py311 = ["abi3-py312", "pyo3-build-config/abi3-py311", "pyo3-ffi/abi3-py311"]
 abi3-py312 = ["abi3-py313", "pyo3-build-config/abi3-py312", "pyo3-ffi/abi3-py312"]
 abi3-py313 = ["abi3-py314", "pyo3-build-config/abi3-py313", "pyo3-ffi/abi3-py313"]
-abi3-py314 = ["abi3", "pyo3-build-config/abi3-py314", "pyo3-ffi/abi3-py314"]
+abi3-py314 = ["abi3-py315", "pyo3-build-config/abi3-py314", "pyo3-ffi/abi3-py314"]
+abi3-py315 = ["abi3", "pyo3-build-config/abi3-py315", "pyo3-ffi/abi3-py315"]
 
 # deprecated: no longer needed, raw-dylib is used instead
 generate-import-lib = ["pyo3-ffi/generate-import-lib"]

guide/src/python-from-rust/calling-existing-code.md

@@ -154,10 +154,13 @@ mod foo {
     }
 }
 
+# #[cfg(not(_Py_OPAQUE_PYOBJECT))]
 fn main() -> PyResult<()> {
     pyo3::append_to_inittab!(foo);
     Python::attach(|py| Python::run(py, c"import foo; foo.add_one(6)", None, None))
 }
+# #[cfg(_Py_OPAQUE_PYOBJECT)]
+# fn main() -> () {}
 ```
 
 If `append_to_inittab` cannot be used due to constraints in the program, an alternative is to create a module using [`PyModule::new`] and insert it manually into `sys.modules`:

noxfile.py

@@ -84,10 +84,7 @@ def _supported_interpreter_versions(
 
 
 PY_VERSIONS = _supported_interpreter_versions("cpython")
-# We don't yet support abi3-py315 but do support cp315 and cp315t
-# version-specific builds
 ABI3_PY_VERSIONS = [p for p in PY_VERSIONS if not p.endswith("t")]
-ABI3_PY_VERSIONS.remove("3.15")
 PYPY_VERSIONS = _supported_interpreter_versions("pypy")
 
 
@@ -126,7 +123,12 @@ def test_rust(session: nox.Session):
         # We need to pass the feature set to the test command
         # so that it can be used in the test code
         # (e.g. for `#[cfg(feature = "abi3-py37")]`)
-        if feature_set and "abi3" in feature_set and FREE_THREADED_BUILD:
+        if (
+            feature_set
+            and "abi3" in feature_set
+            and FREE_THREADED_BUILD
+            and sys.version_info < (3, 15)
+        ):
             # free-threaded builds don't support abi3 yet
             continue
 

pyo3-build-config/Cargo.toml

@@ -39,7 +39,8 @@ abi3-py310 = ["abi3-py311"]
 abi3-py311 = ["abi3-py312"]
 abi3-py312 = ["abi3-py313"]
 abi3-py313 = ["abi3-py314"]
-abi3-py314 = ["abi3"]
+abi3-py314 = ["abi3-py315"]
+abi3-py315 = ["abi3"]
 
 [package.metadata.docs.rs]
 features = ["resolve-config"]

pyo3-build-config/src/impl_.rs

@@ -44,7 +44,7 @@ const MINIMUM_SUPPORTED_VERSION_GRAALPY: PythonVersion = PythonVersion {
 };
 
 /// Maximum Python version that can be used as minimum required Python version with abi3.
-pub(crate) const ABI3_MAX_MINOR: u8 = 14;
+pub(crate) const ABI3_MAX_MINOR: u8 = 15;
 
 #[cfg(test)]
 thread_local! {
@@ -194,8 +194,11 @@ impl InterpreterConfig {
         }
 
         // If Py_GIL_DISABLED is set, do not build with limited API support
-        if self.abi3 && !self.is_free_threaded() {
+        if self.abi3 && !(self.is_free_threaded()) {
             out.push("cargo:rustc-cfg=Py_LIMITED_API".to_owned());
+            if self.version.minor >= 15 {
+                out.push("cargo:rustc-cfg=_Py_OPAQUE_PYOBJECT".to_owned());
+            }
         }
 
         for flag in &self.build_flags.0 {
@@ -3151,6 +3154,31 @@ mod tests {
                 "cargo:rustc-cfg=Py_LIMITED_API".to_owned(),
             ]
         );
+
+        let interpreter_config = InterpreterConfig {
+            implementation: PythonImplementation::CPython,
+            version: PythonVersion {
+                major: 3,
+                minor: 15,
+            },
+            ..interpreter_config
+        };
+        assert_eq!(
+            interpreter_config.build_script_outputs(),
+            [
+                "cargo:rustc-cfg=Py_3_7".to_owned(),
+                "cargo:rustc-cfg=Py_3_8".to_owned(),
+                "cargo:rustc-cfg=Py_3_9".to_owned(),
+                "cargo:rustc-cfg=Py_3_10".to_owned(),
+                "cargo:rustc-cfg=Py_3_11".to_owned(),
+                "cargo:rustc-cfg=Py_3_12".to_owned(),
+                "cargo:rustc-cfg=Py_3_13".to_owned(),
+                "cargo:rustc-cfg=Py_3_14".to_owned(),
+                "cargo:rustc-cfg=Py_3_15".to_owned(),
+                "cargo:rustc-cfg=Py_LIMITED_API".to_owned(),
+                "cargo:rustc-cfg=_Py_OPAQUE_PYOBJECT".to_owned(),
+            ]
+        );
     }
 
     #[test]

pyo3-build-config/src/lib.rs

@@ -264,6 +264,7 @@ pub fn print_expected_cfgs() {
 
     println!("cargo:rustc-check-cfg=cfg(Py_LIMITED_API)");
     println!("cargo:rustc-check-cfg=cfg(Py_GIL_DISABLED)");
+    println!("cargo:rustc-check-cfg=cfg(_Py_OPAQUE_PYOBJECT)");
     println!("cargo:rustc-check-cfg=cfg(PyPy)");
     println!("cargo:rustc-check-cfg=cfg(GraalPy)");
     println!("cargo:rustc-check-cfg=cfg(py_sys_config, values(\"Py_DEBUG\", \"Py_REF_DEBUG\", \"Py_TRACE_REFS\", \"COUNT_ALLOCS\"))");

pyo3-ffi/Cargo.toml

@@ -33,7 +33,8 @@ abi3-py310 = ["abi3-py311", "pyo3-build-config/abi3-py310"]
 abi3-py311 = ["abi3-py312", "pyo3-build-config/abi3-py311"]
 abi3-py312 = ["abi3-py313", "pyo3-build-config/abi3-py312"]
 abi3-py313 = ["abi3-py314", "pyo3-build-config/abi3-py313"]
-abi3-py314 = ["abi3", "pyo3-build-config/abi3-py314"]
+abi3-py314 = ["abi3-py315", "pyo3-build-config/abi3-py314"]
+abi3-py315 = ["abi3", "pyo3-build-config/abi3-py315"]
 
 # deprecated: no longer needed, raw-dylib is used instead
 generate-import-lib = ["pyo3-build-config/generate-import-lib"]

pyo3-ffi/src/moduleobject.rs

@@ -1,3 +1,4 @@
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 use crate::methodobject::PyMethodDef;
 use crate::object::*;
 use crate::pyport::Py_ssize_t;
@@ -49,6 +50,7 @@ extern_libpython! {
     pub static mut PyModuleDef_Type: PyTypeObject;
 }
 
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[repr(C)]
 pub struct PyModuleDef_Base {
     pub ob_base: PyObject,
@@ -58,6 +60,7 @@ pub struct PyModuleDef_Base {
     pub m_copy: *mut PyObject,
 }
 
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[allow(
     clippy::declare_interior_mutable_const,
     reason = "contains atomic refcount on free-threaded builds"
@@ -148,6 +151,7 @@ extern_libpython! {
     pub fn PyModule_GetToken(module: *mut PyObject, result: *mut *mut c_void) -> c_int;
 }
 
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[repr(C)]
 pub struct PyModuleDef {
     pub m_base: PyModuleDef_Base,
@@ -161,3 +165,7 @@ pub struct PyModuleDef {
     pub m_clear: Option<inquiry>,
     pub m_free: Option<freefunc>,
 }
+
+// from pytypedefs.h
+#[cfg(_Py_OPAQUE_PYOBJECT)]
+opaque_struct!(pub PyModuleDef);

pyo3-ffi/src/object.rs

@@ -1,13 +1,16 @@
 use crate::pyport::{Py_hash_t, Py_ssize_t};
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[cfg(Py_GIL_DISABLED)]
 use crate::refcount;
 #[cfg(Py_GIL_DISABLED)]
 use crate::PyMutex;
 use std::ffi::{c_char, c_int, c_uint, c_ulong, c_void};
 use std::mem;
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[cfg(Py_GIL_DISABLED)]
 use std::sync::atomic::{AtomicIsize, AtomicU32};
 
+// from pytypedefs.h
 #[cfg(Py_LIMITED_API)]
 opaque_struct!(pub PyTypeObject);
 
@@ -91,6 +94,7 @@ const _PyObject_MIN_ALIGNMENT: usize = 4;
 // not currently possible to use constant variables with repr(align()), see
 // https://github.com/rust-lang/rust/issues/52840
 
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[cfg_attr(not(all(Py_3_15, Py_GIL_DISABLED)), repr(C))]
 #[cfg_attr(all(Py_3_15, Py_GIL_DISABLED), repr(C, align(4)))]
 #[derive(Debug)]
@@ -116,8 +120,10 @@ pub struct PyObject {
     pub ob_type: *mut PyTypeObject,
 }
 
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 const _: () = assert!(std::mem::align_of::<PyObject>() >= _PyObject_MIN_ALIGNMENT);
 
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[allow(
     clippy::declare_interior_mutable_const,
     reason = "contains atomic refcount on free-threaded builds"
@@ -148,10 +154,15 @@ pub const PyObject_HEAD_INIT: PyObject = PyObject {
     ob_type: std::ptr::null_mut(),
 };
 
+// from pytypedefs.h
+#[cfg(_Py_OPAQUE_PYOBJECT)]
+opaque_struct!(pub PyObject);
+
 // skipped _Py_UNOWNED_TID
 
 // skipped _PyObject_CAST
 
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[repr(C)]
 #[derive(Debug)]
 pub struct PyVarObject {
@@ -163,6 +174,10 @@ pub struct PyVarObject {
     pub _ob_size_graalpy: Py_ssize_t,
 }
 
+// from pytypedefs.h
+#[cfg(_Py_OPAQUE_PYOBJECT)]
+opaque_struct!(pub PyVarObject);
+
 // skipped private _PyVarObject_CAST
 
 #[inline]
@@ -209,6 +224,16 @@ extern_libpython! {
     pub fn Py_TYPE(ob: *mut PyObject) -> *mut PyTypeObject;
 }
 
+#[cfg_attr(windows, link(name = "pythonXY"))]
+#[cfg(all(Py_LIMITED_API, Py_3_15))]
+extern "C" {
+    #[cfg_attr(PyPy, link_name = "PyPy_SIZE")]
+    pub fn Py_SIZE(ob: *mut PyObject) -> Py_ssize_t;
+    #[cfg_attr(PyPy, link_name = "PyPy_IS_TYPE")]
+    pub fn Py_IS_TYPE(ob: *mut PyObject, tp: *mut PyTypeObject) -> c_int;
+    // skipped Py_SET_SIZE
+}
+
 // skip _Py_TYPE compat shim
 
 extern_libpython! {
@@ -218,6 +243,7 @@ extern_libpython! {
     pub static mut PyBool_Type: PyTypeObject;
 }
 
+#[cfg(not(all(Py_LIMITED_API, Py_3_15)))]
 #[inline]
 pub unsafe fn Py_SIZE(ob: *mut PyObject) -> Py_ssize_t {
     #[cfg(not(GraalPy))]
@@ -230,6 +256,7 @@ pub unsafe fn Py_SIZE(ob: *mut PyObject) -> Py_ssize_t {
     _Py_SIZE(ob)
 }
 
+#[cfg(not(all(Py_LIMITED_API, Py_3_15)))]
 #[inline]
 pub unsafe fn Py_IS_TYPE(ob: *mut PyObject, tp: *mut PyTypeObject) -> c_int {
     (Py_TYPE(ob) == tp) as c_int

pyo3-ffi/src/refcount.rs

@@ -11,7 +11,7 @@ use std::ffi::c_uint;
 #[cfg(all(Py_3_14, not(Py_GIL_DISABLED)))]
 use std::ffi::c_ulong;
 use std::ptr;
-#[cfg(Py_GIL_DISABLED)]
+#[cfg(all(Py_GIL_DISABLED, not(Py_LIMITED_API)))]
 use std::sync::atomic::Ordering::Relaxed;
 
 #[cfg(all(Py_3_14, not(Py_3_15)))]
@@ -116,6 +116,7 @@ pub unsafe fn Py_REFCNT(ob: *mut PyObject) -> Py_ssize_t {
     }
 }
 
+#[cfg(not(_Py_OPAQUE_PYOBJECT))]
 #[cfg(Py_3_12)]
 #[inline(always)]
 unsafe fn _Py_IsImmortal(op: *mut PyObject) -> c_int {

src/impl_/pyclass.rs

@@ -1455,6 +1455,7 @@ pub trait ExtractPyClassWithClone {}
 #[cfg(test)]
 #[cfg(feature = "macros")]
 mod tests {
+    #[cfg(not(_Py_OPAQUE_PYOBJECT))]
     use crate::pycell::impl_::PyClassObjectContents;
 
     use super::*;
@@ -1483,17 +1484,19 @@ mod tests {
             Some(PyMethodDefType::StructMember(member)) => {
                 assert_eq!(unsafe { CStr::from_ptr(member.name) }, c"value");
                 assert_eq!(member.type_code, ffi::Py_T_OBJECT_EX);
+                #[cfg(not(_Py_OPAQUE_PYOBJECT))]
                 #[repr(C)]
                 struct ExpectedLayout {
                     ob_base: ffi::PyObject,
                     contents: PyClassObjectContents<FrozenClass>,
                 }
+                #[cfg(not(_Py_OPAQUE_PYOBJECT))]
                 assert_eq!(
                     member.offset,
                     (offset_of!(ExpectedLayout, contents) + offset_of!(FrozenClass, value))
                         as ffi::Py_ssize_t
                 );
-                assert_eq!(member.flags, ffi::Py_READONLY);
+                assert_eq!(member.flags & ffi::Py_READONLY, ffi::Py_READONLY);
             }
             _ => panic!("Expected a StructMember"),
         }
@@ -1605,17 +1608,17 @@ mod tests {
         // SAFETY: def.doc originated from a CStr
         assert_eq!(unsafe { CStr::from_ptr(def.doc) }, c"My field doc");
         assert_eq!(def.type_code, ffi::Py_T_OBJECT_EX);
-        #[allow(irrefutable_let_patterns)]
-        let PyObjectOffset::Absolute(contents_offset) =
-            <MyClass as PyClassImpl>::Layout::CONTENTS_OFFSET
-        else {
-            panic!()
+        #[allow(clippy::infallible_destructuring_match)]
+        let contents_offset = match <MyClass as PyClassImpl>::Layout::CONTENTS_OFFSET {
+            PyObjectOffset::Absolute(contents_offset) => contents_offset,
+            #[cfg(Py_3_12)]
+            PyObjectOffset::Relative(contents_offset) => contents_offset,
         };
         assert_eq!(
             def.offset,
             contents_offset + FIELD_OFFSET as ffi::Py_ssize_t
         );
-        assert_eq!(def.flags, ffi::Py_READONLY);
+        assert_eq!(def.flags & ffi::Py_READONLY, ffi::Py_READONLY);
     }
 
     #[test]