use PyO3 types within LazyTypeObject

guide/src/class.md

@@ -981,6 +981,7 @@ unsafe impl pyo3::type_object::PyTypeInfo for MyClass {
     fn type_object_raw(py: pyo3::Python<'_>) -> *mut pyo3::ffi::PyTypeObject {
         <Self as pyo3::impl_::pyclass::PyClassImpl>::lazy_type_object()
             .get_or_init(py)
+            .as_type_ptr()
     }
 }
 

pyo3-macros-backend/src/pyclass.rs

@@ -758,6 +758,7 @@ fn impl_pytypeinfo(
 
                 <#cls as _pyo3::impl_::pyclass::PyClassImpl>::lazy_type_object()
                     .get_or_init(py)
+                    .as_type_ptr()
             }
         }
     }

src/impl_/pyclass/lazy_type_object.rs

@@ -9,7 +9,8 @@ use parking_lot::{const_mutex, Mutex};
 
 use crate::{
     exceptions::PyRuntimeError, ffi, once_cell::GILOnceCell, pyclass::create_type_object,
-    IntoPyPointer, PyClass, PyErr, PyMethodDefType, PyObject, PyResult, Python,
+    types::PyType, AsPyPointer, IntoPyPointer, Py, PyClass, PyErr, PyMethodDefType, PyObject,
+    PyResult, Python,
 };
 
 use super::PyClassItemsIter;
@@ -20,11 +21,11 @@ pub struct LazyTypeObject<T>(LazyTypeObjectInner, PhantomData<T>);
 
 // Non-generic inner of LazyTypeObject to keep code size down
 struct LazyTypeObjectInner {
-    value: GILOnceCell<*mut ffi::PyTypeObject>,
+    value: GILOnceCell<Py<PyType>>,
     // Threads which have begun initialization of the `tp_dict`. Used for
     // reentrant initialization detection.
     initializing_threads: Mutex<Vec<ThreadId>>,
-    tp_dict_filled: GILOnceCell<PyResult<()>>,
+    tp_dict_filled: GILOnceCell<()>,
 }
 
 impl<T> LazyTypeObject<T> {
@@ -43,7 +44,7 @@ impl<T> LazyTypeObject<T> {
 
 impl<T: PyClass> LazyTypeObject<T> {
     /// Gets the type object contained by this `LazyTypeObject`, initializing it if needed.
-    pub fn get_or_init(&self, py: Python<'_>) -> *mut ffi::PyTypeObject {
+    pub fn get_or_init<'py>(&'py self, py: Python<'py>) -> &'py PyType {
         self.get_or_try_init(py).unwrap_or_else(|err| {
             err.print(py);
             panic!("failed to create type object for {}", T::NAME)
@@ -51,31 +52,26 @@ impl<T: PyClass> LazyTypeObject<T> {
     }
 
     /// Fallible version of the above.
-    pub(crate) fn get_or_try_init(&self, py: Python<'_>) -> PyResult<*mut ffi::PyTypeObject> {
-        fn inner<T: PyClass>() -> PyResult<*mut ffi::PyTypeObject> {
-            // Safety: `py` is held by the caller of `get_or_init`.
-            let py = unsafe { Python::assume_gil_acquired() };
-            create_type_object::<T>(py)
-        }
-
+    pub(crate) fn get_or_try_init<'py>(&'py self, py: Python<'py>) -> PyResult<&'py PyType> {
         self.0
-            .get_or_try_init(py, inner::<T>, T::NAME, T::items_iter())
+            .get_or_try_init(py, create_type_object::<T>, T::NAME, T::items_iter())
     }
 }
 
 impl LazyTypeObjectInner {
-    fn get_or_try_init(
-        &self,
-        py: Python<'_>,
-        init: fn() -> PyResult<*mut ffi::PyTypeObject>,
+    // Uses dynamically dispatched fn(Python<'py>) -> PyResult<Py<PyType>
+    // so that this code is only instantiated once, instead of for every T
+    // like the generic LazyTypeObject<T> methods above.
+    fn get_or_try_init<'py>(
+        &'py self,
+        py: Python<'py>,
+        init: fn(Python<'py>) -> PyResult<Py<PyType>>,
         name: &str,
         items_iter: PyClassItemsIter,
-    ) -> PyResult<*mut ffi::PyTypeObject> {
+    ) -> PyResult<&'py PyType> {
         (|| -> PyResult<_> {
-            // Uses explicit GILOnceCell::get_or_init::<fn() -> *mut ffi::PyTypeObject> monomorphization
-            // so that this code is only monomorphized once, instead of for every T.
-            let type_object = *self.value.get_or_try_init(py, init)?;
-            self.ensure_init(py, type_object, name, items_iter)?;
+            let type_object = self.value.get_or_try_init(py, || init(py))?.as_ref(py);
+            self.ensure_init(type_object, name, items_iter)?;
             Ok(type_object)
         })()
         .map_err(|err| {
@@ -89,11 +85,12 @@ impl LazyTypeObjectInner {
 
     fn ensure_init(
         &self,
-        py: Python<'_>,
-        type_object: *mut ffi::PyTypeObject,
+        type_object: &PyType,
         name: &str,
         items_iter: PyClassItemsIter,
     ) -> PyResult<()> {
+        let py = type_object.py();
+
         // We might want to fill the `tp_dict` with python instances of `T`
         // itself. In order to do so, we must first initialize the type object
         // with an empty `tp_dict`: now we can create instances of `T`.
@@ -167,8 +164,8 @@ impl LazyTypeObjectInner {
 
         // Now we hold the GIL and we can assume it won't be released until we
         // return from the function.
-        let result = self.tp_dict_filled.get_or_init(py, move || {
-            let result = initialize_tp_dict(py, type_object as *mut ffi::PyObject, items);
+        let result = self.tp_dict_filled.get_or_try_init(py, move || {
+            let result = initialize_tp_dict(py, type_object.as_ptr(), items);
 
             // Initialization successfully complete, can clear the thread list.
             // (No further calls to get_or_init() will try to init, on any thread.)

src/pyclass/create_type_object.rs

@@ -5,7 +5,8 @@ use crate::{
         assign_sequence_item_from_mapping, get_sequence_item_from_mapping, tp_dealloc,
         PyClassItemsIter,
     },
-    PyClass, PyErr, PyMethodDefType, PyResult, PyTypeInfo, Python,
+    types::PyType,
+    Py, PyClass, PyMethodDefType, PyResult, PyTypeInfo, Python,
 };
 use std::{
     collections::HashMap,
@@ -15,7 +16,7 @@ use std::{
     ptr,
 };
 
-pub(crate) fn create_type_object<T>(py: Python<'_>) -> PyResult<*mut ffi::PyTypeObject>
+pub(crate) fn create_type_object<T>(py: Python<'_>) -> PyResult<Py<PyType>>
 where
     T: PyClass,
 {
@@ -322,7 +323,7 @@ impl PyTypeBuilder {
         name: &'static str,
         module_name: Option<&'static str>,
         basicsize: usize,
-    ) -> PyResult<*mut ffi::PyTypeObject> {
+    ) -> PyResult<Py<PyType>> {
         // `c_ulong` and `c_uint` have the same size
         // on some platforms (like windows)
         #![allow(clippy::useless_conversion)]
@@ -370,16 +371,14 @@ impl PyTypeBuilder {
         };
 
         // Safety: We've correctly setup the PyType_Spec at this point
-        let type_object = unsafe { ffi::PyType_FromSpec(&mut spec) };
-        if type_object.is_null() {
-            Err(PyErr::fetch(py))
-        } else {
-            for cleanup in std::mem::take(&mut self.cleanup) {
-                cleanup(&self, type_object as _);
-            }
+        let type_object: Py<PyType> =
+            unsafe { Py::from_owned_ptr_or_err(py, ffi::PyType_FromSpec(&mut spec))? };
 
-            Ok(type_object as _)
+        for cleanup in std::mem::take(&mut self.cleanup) {
+            cleanup(&self, type_object.as_ref(py).as_type_ptr());
         }
+
+        Ok(type_object)
     }
 }
 

src/types/module.rs

@@ -7,7 +7,7 @@ use crate::err::{PyErr, PyResult};
 use crate::exceptions;
 use crate::ffi;
 use crate::pyclass::PyClass;
-use crate::types::{PyAny, PyCFunction, PyDict, PyList, PyString, PyType};
+use crate::types::{PyAny, PyCFunction, PyDict, PyList, PyString};
 use crate::{AsPyPointer, IntoPy, Py, PyObject, Python};
 use std::ffi::{CStr, CString};
 use std::str;
@@ -295,9 +295,7 @@ impl PyModule {
         T: PyClass,
     {
         let py = self.py();
-        self.add(T::NAME, unsafe {
-            PyType::from_type_ptr(py, T::lazy_type_object().get_or_try_init(py)?)
-        })
+        self.add(T::NAME, T::lazy_type_object().get_or_try_init(py)?)
     }
 
     /// Adds a function or a (sub)module to a module, using the functions name as name.

tests/test_class_attributes.rs

@@ -1,6 +1,6 @@
 #![cfg(feature = "macros")]
 
-use pyo3::{exceptions::PyValueError, prelude::*, types::PyString};
+use pyo3::{prelude::*, types::PyString};
 
 mod common;
 
@@ -98,6 +98,8 @@ fn recursive_class_attributes() {
 #[test]
 #[cfg(panic = "unwind")]
 fn test_fallible_class_attribute() {
+    use pyo3::exceptions::PyValueError;
+
     #[pyclass]
     struct BrokenClass;