feature gate HasPyGilRef completely

Author: Icxolu

src/instance.rs

@@ -2,6 +2,7 @@ use crate::err::{self, PyErr, PyResult};
 use crate::impl_::pycell::PyClassObject;
 use crate::pycell::{PyBorrowError, PyBorrowMutError};
 use crate::pyclass::boolean_struct::{False, True};
+#[cfg(feature = "gil-refs")]
 use crate::type_object::HasPyGilRef;
 use crate::types::{any::PyAnyMethods, string::PyStringMethods, typeobject::PyTypeMethods};
 use crate::types::{DerefToPyAny, PyDict, PyString, PyTuple};
@@ -667,11 +668,11 @@ impl<'a, 'py, T> From<&'a Bound<'py, T>> for Borrowed<'a, 'py, T> {
     }
 }
 
+#[cfg(feature = "gil-refs")]
 impl<'py, T> Borrowed<'py, 'py, T>
 where
     T: HasPyGilRef,
 {
-    #[cfg(feature = "gil-refs")]
     pub(crate) fn into_gil_ref(self) -> &'py T::AsRefTarget {
         // Safety: self is a borrow over `'py`.
         #[allow(deprecated)]
@@ -954,6 +955,7 @@ where
     }
 }
 
+#[cfg(feature = "gil-refs")]
 impl<T> Py<T>
 where
     T: HasPyGilRef,
@@ -1001,7 +1003,6 @@ where
     ///     assert!(my_class_cell.try_borrow().is_ok());
     /// });
     /// ```
-    #[cfg(feature = "gil-refs")]
     #[deprecated(
         since = "0.21.0",
         note = "use `obj.bind(py)` instead of `obj.as_ref(py)`"
@@ -1054,7 +1055,6 @@ where
     ///     obj.into_ref(py)
     /// }
     /// ```
-    #[cfg(feature = "gil-refs")]
     #[deprecated(
         since = "0.21.0",
         note = "use `obj.into_bound(py)` instead of `obj.into_ref(py)`"

src/type_object.rs

@@ -31,9 +31,9 @@ pub trait PySizedLayout<T>: PyLayout<T> + Sized {}
 ///
 /// - `Py<Self>::as_ref` will hand out references to `Self::AsRefTarget`.
 /// - `Self::AsRefTarget` must have the same layout as `UnsafeCell<ffi::PyAny>`.
+#[cfg(feature = "gil-refs")]
 pub unsafe trait HasPyGilRef {
     /// Utility type to make Py::as_ref work.
-    #[cfg(feature = "gil-refs")]
     type AsRefTarget: PyNativeType;
 }
 
@@ -45,9 +45,6 @@ where
     type AsRefTarget = Self;
 }
 
-#[cfg(not(feature = "gil-refs"))]
-unsafe impl<T> HasPyGilRef for T {}
-
 /// Python type information.
 /// All Python native types (e.g., `PyDict`) and `#[pyclass]` structs implement this trait.
 ///
@@ -61,6 +58,7 @@ unsafe impl<T> HasPyGilRef for T {}
 ///
 /// Implementations must provide an implementation for `type_object_raw` which infallibly produces a
 /// non-null pointer to the corresponding Python type object.
+#[cfg(feature = "gil-refs")]
 pub unsafe trait PyTypeInfo: Sized + HasPyGilRef {
     /// Class name.
     const NAME: &'static str;
@@ -139,7 +137,62 @@ pub unsafe trait PyTypeInfo: Sized + HasPyGilRef {
     }
 }
 
+/// Python type information.
+/// All Python native types (e.g., `PyDict`) and `#[pyclass]` structs implement this trait.
+///
+/// This trait is marked unsafe because:
+///  - specifying the incorrect layout can lead to memory errors
+///  - the return value of type_object must always point to the same PyTypeObject instance
+///
+/// It is safely implemented by the `pyclass` macro.
+///
+/// # Safety
+///
+/// Implementations must provide an implementation for `type_object_raw` which infallibly produces a
+/// non-null pointer to the corresponding Python type object.
+#[cfg(not(feature = "gil-refs"))]
+pub unsafe trait PyTypeInfo: Sized {
+    /// Class name.
+    const NAME: &'static str;
+
+    /// Module name, if any.
+    const MODULE: Option<&'static str>;
+
+    /// Returns the PyTypeObject instance for this type.
+    fn type_object_raw(py: Python<'_>) -> *mut ffi::PyTypeObject;
+
+    /// Returns the safe abstraction over the type object.
+    #[inline]
+    fn type_object_bound(py: Python<'_>) -> Bound<'_, PyType> {
+        // Making the borrowed object `Bound` is necessary for soundness reasons. It's an extreme
+        // edge case, but arbitrary Python code _could_ change the __class__ of an object and cause
+        // the type object to be freed.
+        //
+        // By making `Bound` we assume ownership which is then safe against races.
+        unsafe {
+            Self::type_object_raw(py)
+                .cast::<ffi::PyObject>()
+                .assume_borrowed_unchecked(py)
+                .to_owned()
+                .downcast_into_unchecked()
+        }
+    }
+
+    /// Checks if `object` is an instance of this type or a subclass of this type.
+    #[inline]
+    fn is_type_of_bound(object: &Bound<'_, PyAny>) -> bool {
+        unsafe { ffi::PyObject_TypeCheck(object.as_ptr(), Self::type_object_raw(object.py())) != 0 }
+    }
+
+    /// Checks if `object` is an instance of this type.
+    #[inline]
+    fn is_exact_type_of_bound(object: &Bound<'_, PyAny>) -> bool {
+        unsafe { ffi::Py_TYPE(object.as_ptr()) == Self::type_object_raw(object.py()) }
+    }
+}
+
 /// Implemented by types which can be used as a concrete Python type inside `Py<T>` smart pointers.
+#[cfg(feature = "gil-refs")]
 pub trait PyTypeCheck: HasPyGilRef {
     /// Name of self. This is used in error messages, for example.
     const NAME: &'static str;
@@ -150,6 +203,18 @@ pub trait PyTypeCheck: HasPyGilRef {
     fn type_check(object: &Bound<'_, PyAny>) -> bool;
 }
 
+/// Implemented by types which can be used as a concrete Python type inside `Py<T>` smart pointers.
+#[cfg(not(feature = "gil-refs"))]
+pub trait PyTypeCheck {
+    /// Name of self. This is used in error messages, for example.
+    const NAME: &'static str;
+
+    /// Checks if `object` is an instance of `Self`, which may include a subtype.
+    ///
+    /// This should be equivalent to the Python expression `isinstance(object, Self)`.
+    fn type_check(object: &Bound<'_, PyAny>) -> bool;
+}
+
 impl<T> PyTypeCheck for T
 where
     T: PyTypeInfo,