Implement PyTypeInfo for PyEllipsis, PyNone, and `PyNotImplemen…

…ted`

newsfragments/3577.added.md

@@ -0,0 +1 @@
+Implement `PyTypeInfo` for `PyEllipsis`, `PyNone` and `PyNotImplemented`.

newsfragments/3577.changed.md

@@ -0,0 +1 @@
+Deprecate `Py::is_ellipsis` and `PyAny::is_ellipsis` in favour of `any.is(py.Ellipsis())`.

src/instance.rs

@@ -776,6 +776,7 @@ impl<T> Py<T> {
     /// Returns whether the object is Ellipsis, e.g. `...`.
     ///
     /// This is equivalent to the Python expression `self is ...`.
+    #[deprecated(since = "0.20.0", note = "use `.is(py.Ellipsis())` instead")]
     pub fn is_ellipsis(&self) -> bool {
         unsafe { ffi::Py_Ellipsis() == self.as_ptr() }
     }
@@ -1474,6 +1475,7 @@ a = A()
     }
 
     #[test]
+    #[allow(deprecated)]
     fn test_is_ellipsis() {
         Python::with_gil(|py| {
             let v = py

src/types/any.rs

@@ -653,6 +653,7 @@ impl PyAny {
     /// Returns whether the object is Ellipsis, e.g. `...`.
     ///
     /// This is equivalent to the Python expression `self is ...`.
+    #[deprecated(since = "0.20.0", note = "use `.is(py.Ellipsis())` instead")]
     pub fn is_ellipsis(&self) -> bool {
         Py2::<PyAny>::borrowed_from_gil_ref(&self).is_ellipsis()
     }
@@ -2557,6 +2558,7 @@ class SimpleClass:
     }
 
     #[test]
+    #[allow(deprecated)]
     fn test_is_ellipsis() {
         Python::with_gil(|py| {
             let v = py

src/types/ellipsis.rs

@@ -1,4 +1,4 @@
-use crate::{ffi, PyAny, PyDowncastError, PyTryFrom, Python};
+use crate::{ffi, PyAny, PyTypeInfo, Python};
 
 /// Represents the Python `Ellipsis` object.
 #[repr(transparent)]
@@ -15,39 +15,48 @@ impl PyEllipsis {
     }
 }
 
-impl<'v> PyTryFrom<'v> for PyEllipsis {
-    fn try_from<V: Into<&'v PyAny>>(value: V) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        let value: &PyAny = value.into();
-        if unsafe { ffi::Py_Ellipsis() == value.as_ptr() } {
-            return unsafe { Ok(value.downcast_unchecked()) };
-        }
-        Err(PyDowncastError::new(value, "ellipsis"))
+unsafe impl PyTypeInfo for PyEllipsis {
+    const NAME: &'static str = "ellipsis";
+
+    const MODULE: Option<&'static str> = None;
+
+    type AsRefTarget = PyEllipsis;
+
+    fn type_object_raw(_py: Python<'_>) -> *mut ffi::PyTypeObject {
+        unsafe { ffi::Py_TYPE(ffi::Py_Ellipsis()) }
     }
 
-    fn try_from_exact<V: Into<&'v PyAny>>(
-        value: V,
-    ) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        value.into().downcast()
+    #[inline]
+    fn is_type_of(object: &PyAny) -> bool {
+        // ellipsis is not usable as a base type
+        Self::is_exact_type_of(object)
     }
 
-    unsafe fn try_from_unchecked<V: Into<&'v PyAny>>(value: V) -> &'v Self {
-        let ptr = value.into() as *const _ as *const PyEllipsis;
-        &*ptr
+    #[inline]
+    fn is_exact_type_of(object: &PyAny) -> bool {
+        object.is(Self::get(object.py()))
     }
 }
 
 #[cfg(test)]
 mod tests {
     use crate::types::{PyDict, PyEllipsis};
-    use crate::Python;
+    use crate::{PyTypeInfo, Python};
 
     #[test]
     fn test_ellipsis_is_itself() {
+        Python::with_gil(|py| {
+            assert!(PyEllipsis::get(py).is_instance_of::<PyEllipsis>());
+            assert!(PyEllipsis::get(py).is_exact_instance_of::<PyEllipsis>());
+        })
+    }
+
+    #[test]
+    fn test_ellipsis_type_object_consistent() {
         Python::with_gil(|py| {
             assert!(PyEllipsis::get(py)
-                .downcast::<PyEllipsis>()
-                .unwrap()
-                .is_ellipsis());
+                .get_type()
+                .is(PyEllipsis::type_object(py)));
         })
     }
 

src/types/none.rs

@@ -1,4 +1,4 @@
-use crate::{ffi, IntoPy, PyAny, PyDowncastError, PyObject, PyTryFrom, Python, ToPyObject};
+use crate::{ffi, IntoPy, PyAny, PyObject, PyTypeInfo, Python, ToPyObject};
 
 /// Represents the Python `None` object.
 #[repr(transparent)]
@@ -15,24 +15,26 @@ impl PyNone {
     }
 }
 
-impl<'v> PyTryFrom<'v> for PyNone {
-    fn try_from<V: Into<&'v PyAny>>(value: V) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        let value: &PyAny = value.into();
-        if value.is_none() {
-            return unsafe { Ok(value.downcast_unchecked()) };
-        }
-        Err(PyDowncastError::new(value, "NoneType"))
+unsafe impl PyTypeInfo for PyNone {
+    const NAME: &'static str = "NoneType";
+
+    const MODULE: Option<&'static str> = None;
+
+    type AsRefTarget = PyNone;
+
+    fn type_object_raw(_py: Python<'_>) -> *mut ffi::PyTypeObject {
+        unsafe { ffi::Py_TYPE(ffi::Py_None()) }
     }
 
-    fn try_from_exact<V: Into<&'v PyAny>>(
-        value: V,
-    ) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        value.into().downcast()
+    #[inline]
+    fn is_type_of(object: &PyAny) -> bool {
+        // NoneType is not usable as a base type
+        Self::is_exact_type_of(object)
     }
 
-    unsafe fn try_from_unchecked<V: Into<&'v PyAny>>(value: V) -> &'v Self {
-        let ptr = value.into() as *const _ as *const PyNone;
-        &*ptr
+    #[inline]
+    fn is_exact_type_of(object: &PyAny) -> bool {
+        object.is(Self::get(object.py()))
     }
 }
 
@@ -53,7 +55,22 @@ impl IntoPy<PyObject> for () {
 #[cfg(test)]
 mod tests {
     use crate::types::{PyDict, PyNone};
-    use crate::{IntoPy, PyObject, Python, ToPyObject};
+    use crate::{IntoPy, PyObject, PyTypeInfo, Python, ToPyObject};
+
+    #[test]
+    fn test_none_is_itself() {
+        Python::with_gil(|py| {
+            assert!(PyNone::get(py).is_instance_of::<PyNone>());
+            assert!(PyNone::get(py).is_exact_instance_of::<PyNone>());
+        })
+    }
+
+    #[test]
+    fn test_none_type_object_consistent() {
+        Python::with_gil(|py| {
+            assert!(PyNone::get(py).get_type().is(PyNone::type_object(py)));
+        })
+    }
 
     #[test]
     fn test_none_is_none() {

src/types/notimplemented.rs

@@ -1,4 +1,4 @@
-use crate::{ffi, PyAny, PyDowncastError, PyTryFrom, Python};
+use crate::{ffi, PyAny, PyTypeInfo, Python};
 
 /// Represents the Python `NotImplemented` object.
 #[repr(transparent)]
@@ -15,39 +15,48 @@ impl PyNotImplemented {
     }
 }
 
-impl<'v> PyTryFrom<'v> for PyNotImplemented {
-    fn try_from<V: Into<&'v PyAny>>(value: V) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        let value: &PyAny = value.into();
-        if unsafe { ffi::Py_NotImplemented() == value.as_ptr() } {
-            return unsafe { Ok(value.downcast_unchecked()) };
-        }
-        Err(PyDowncastError::new(value, "NotImplementedType"))
+unsafe impl PyTypeInfo for PyNotImplemented {
+    const NAME: &'static str = "NotImplementedType";
+
+    const MODULE: Option<&'static str> = None;
+
+    type AsRefTarget = PyNotImplemented;
+
+    fn type_object_raw(_py: Python<'_>) -> *mut ffi::PyTypeObject {
+        unsafe { ffi::Py_TYPE(ffi::Py_NotImplemented()) }
     }
 
-    fn try_from_exact<V: Into<&'v PyAny>>(
-        value: V,
-    ) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        value.into().downcast()
+    #[inline]
+    fn is_type_of(object: &PyAny) -> bool {
+        // NotImplementedType is not usable as a base type
+        Self::is_exact_type_of(object)
     }
 
-    unsafe fn try_from_unchecked<V: Into<&'v PyAny>>(value: V) -> &'v Self {
-        let ptr = value.into() as *const _ as *const PyNotImplemented;
-        &*ptr
+    #[inline]
+    fn is_exact_type_of(object: &PyAny) -> bool {
+        object.is(Self::get(object.py()))
     }
 }
 
 #[cfg(test)]
 mod tests {
     use crate::types::{PyDict, PyNotImplemented};
-    use crate::Python;
+    use crate::{PyTypeInfo, Python};
 
     #[test]
     fn test_notimplemented_is_itself() {
+        Python::with_gil(|py| {
+            assert!(PyNotImplemented::get(py).is_instance_of::<PyNotImplemented>());
+            assert!(PyNotImplemented::get(py).is_exact_instance_of::<PyNotImplemented>());
+        })
+    }
+
+    #[test]
+    fn test_notimplemented_type_object_consistent() {
         Python::with_gil(|py| {
             assert!(PyNotImplemented::get(py)
-                .downcast::<PyNotImplemented>()
-                .unwrap()
-                .is(py.NotImplemented()));
+                .get_type()
+                .is(PyNotImplemented::type_object(py)));
         })
     }