adding new getter for type obj (#4197)

* adding new getter for type obj

* fixing limited api build

* fix formating ssues from clippy

* add changelog info

* Update newsfragments/4197.added.md

Co-authored-by: David Hewitt <mail@davidhewitt.dev>

* Update src/types/typeobject.rs

Co-authored-by: David Hewitt <mail@davidhewitt.dev>

* Update src/types/typeobject.rs

Co-authored-by: David Hewitt <mail@davidhewitt.dev>

* Update src/types/typeobject.rs

Co-authored-by: David Hewitt <mail@davidhewitt.dev>

* Update src/types/typeobject.rs

Co-authored-by: David Hewitt <mail@davidhewitt.dev>

* using uncheck downcast

* fix formating

* move import

* Update src/types/typeobject.rs

Co-authored-by: Matt Hooks <me@matthooks.com>

* Update src/types/typeobject.rs

Co-authored-by: Matt Hooks <me@matthooks.com>

---------

Co-authored-by: David Hewitt <mail@davidhewitt.dev>
Co-authored-by: Matt Hooks <me@matthooks.com>

newsfragments/4197.added.md

@@ -0,0 +1 @@
+Add `PyTypeMethods::mro` and `PyTypeMethods::bases`.

src/types/typeobject.rs

@@ -1,6 +1,7 @@
 use crate::err::{self, PyResult};
 use crate::instance::Borrowed;
 use crate::types::any::PyAnyMethods;
+use crate::types::PyTuple;
 #[cfg(feature = "gil-refs")]
 use crate::PyNativeType;
 use crate::{ffi, Bound, PyAny, PyTypeInfo, Python};
@@ -127,6 +128,16 @@ pub trait PyTypeMethods<'py>: crate::sealed::Sealed {
  fn is_subclass_of<T>(&self) -> PyResult<bool>
  where
  T: PyTypeInfo;
+
+ /// Return the method resolution order for this type.
+ ///
+ /// Equivalent to the Python expression `self.__mro__`.
+ fn mro(&self) -> Bound<'py, PyTuple>;
+
+ /// Return Python bases
+ ///
+ /// Equivalent to the Python expression `self.__bases__`.
+ fn bases(&self) -> Bound<'py, PyTuple>;
 }
 
 impl<'py> PyTypeMethods<'py> for Bound<'py, PyType> {
@@ -177,6 +188,48 @@ impl<'py> PyTypeMethods<'py> for Bound<'py, PyType> {
  {
  self.is_subclass(&T::type_object_bound(self.py()))
  }
+
+ fn mro(&self) -> Bound<'py, PyTuple> {
+ #[cfg(any(Py_LIMITED_API, PyPy))]
+ let mro = self
+ .getattr(intern!(self.py(), "__mro__"))
+ .expect("Cannot get `__mro__` from object.")
+ .extract()
+ .expect("Unexpected type in `__mro__` attribute.");
+
+ #[cfg(not(any(Py_LIMITED_API, PyPy)))]
+ let mro = unsafe {
+ use crate::ffi_ptr_ext::FfiPtrExt;
+ (*self.as_type_ptr())
+ .tp_mro
+ .assume_borrowed(self.py())
+ .to_owned()
+ .downcast_into_unchecked()
+ };
+
+ mro
+ }
+
+ fn bases(&self) -> Bound<'py, PyTuple> {
+ #[cfg(any(Py_LIMITED_API, PyPy))]
+ let bases = self
+ .getattr(intern!(self.py(), "__bases__"))
+ .expect("Cannot get `__bases__` from object.")
+ .extract()
+ .expect("Unexpected type in `__bases__` attribute.");
+
+ #[cfg(not(any(Py_LIMITED_API, PyPy)))]
+ let bases = unsafe {
+ use crate::ffi_ptr_ext::FfiPtrExt;
+ (*self.as_type_ptr())
+ .tp_bases
+ .assume_borrowed(self.py())
+ .to_owned()
+ .downcast_into_unchecked()
+ };
+
+ bases
+ }
 }
 
 impl<'a> Borrowed<'a, '_, PyType> {
@@ -215,8 +268,8 @@ impl<'a> Borrowed<'a, '_, PyType> {
 
 #[cfg(test)]
 mod tests {
- use crate::types::typeobject::PyTypeMethods;
- use crate::types::{PyBool, PyLong};
+ use crate::types::{PyAnyMethods, PyBool, PyInt, PyLong, PyTuple, PyTypeMethods};
+ use crate::PyAny;
  use crate::Python;
 
  #[test]
@@ -237,4 +290,44 @@ mod tests {
  .unwrap());
  });
  }
+
+ #[test]
+ fn test_mro() {
+ Python::with_gil(|py| {
+ assert!(py
+ .get_type_bound::<PyBool>()
+ .mro()
+ .eq(PyTuple::new_bound(
+ py,
+ [
+ py.get_type_bound::<PyBool>(),
+ py.get_type_bound::<PyInt>(),
+ py.get_type_bound::<PyAny>()
+ ]
+ ))
+ .unwrap());
+ });
+ }
+
+ #[test]
+ fn test_bases_bool() {
+ Python::with_gil(|py| {
+ assert!(py
+ .get_type_bound::<PyBool>()
+ .bases()
+ .eq(PyTuple::new_bound(py, [py.get_type_bound::<PyInt>()]))
+ .unwrap());
+ });
+ }
+
+ #[test]
+ fn test_bases_object() {
+ Python::with_gil(|py| {
+ assert!(py
+ .get_type_bound::<PyAny>()
+ .bases()
+ .eq(PyTuple::empty_bound(py))
+ .unwrap());
+ });
+ }
 }