Add missing #[allow(unsafe_code)] attributes (#4396)

Fixes #4394.

Author: LilyAcorn

newsfragments/4396.fixed.md

@@ -0,0 +1 @@
+Hide confusing warnings about unsafe usage in `#[pyclass]` implementation.

pyo3-macros-backend/src/pyclass.rs

@@ -1744,6 +1744,7 @@ fn impl_pytypeinfo(cls: &syn::Ident, attr: &PyClassArgs, ctx: &Ctx) -> TokenStre
     };
 
     quote! {
+        #[allow(unsafe_code)]
         unsafe impl #pyo3_path::type_object::PyTypeInfo for #cls {
             const NAME: &'static str = #cls_name;
             const MODULE: ::std::option::Option<&'static str> = #module;

pyo3-macros-backend/src/pymethod.rs

@@ -772,13 +772,15 @@ pub fn impl_py_getter_def(
                     use #pyo3_path::impl_::pyclass::Probe;
 
                     struct Offset;
+                    #[allow(unsafe_code)]
                     unsafe impl #pyo3_path::impl_::pyclass::OffsetCalculator<#cls, #ty> for Offset {
                         fn offset() -> usize {
                             #pyo3_path::impl_::pyclass::class_offset::<#cls>() +
                             #pyo3_path::impl_::pyclass::offset_of!(#cls, #field)
                         }
                     }
 
+                    #[allow(unsafe_code)]
                     const GENERATOR: #pyo3_path::impl_::pyclass::PyClassGetterGenerator::<
                         #cls,
                         #ty,

src/impl_/pyclass.rs

@@ -346,6 +346,7 @@ slot_fragment_trait! {
 #[macro_export]
 macro_rules! generate_pyclass_getattro_slot {
     ($cls:ty) => {{
+        #[allow(unsafe_code)]
         unsafe extern "C" fn __wrap(
             _slf: *mut $crate::ffi::PyObject,
             attr: *mut $crate::ffi::PyObject,
@@ -429,6 +430,7 @@ macro_rules! define_pyclass_setattr_slot {
         #[macro_export]
         macro_rules! $generate_macro {
             ($cls:ty) => {{
+                #[allow(unsafe_code)]
                 unsafe extern "C" fn __wrap(
                     _slf: *mut $crate::ffi::PyObject,
                     attr: *mut $crate::ffi::PyObject,
@@ -545,6 +547,7 @@ macro_rules! define_pyclass_binary_operator_slot {
         #[macro_export]
         macro_rules! $generate_macro {
             ($cls:ty) => {{
+                #[allow(unsafe_code)]
                 unsafe extern "C" fn __wrap(
                     _slf: *mut $crate::ffi::PyObject,
                     _other: *mut $crate::ffi::PyObject,
@@ -737,6 +740,7 @@ slot_fragment_trait! {
 #[macro_export]
 macro_rules! generate_pyclass_pow_slot {
     ($cls:ty) => {{
+        #[allow(unsafe_code)]
         unsafe extern "C" fn __wrap(
             _slf: *mut $crate::ffi::PyObject,
             _other: *mut $crate::ffi::PyObject,
@@ -861,7 +865,7 @@ macro_rules! generate_pyclass_richcompare_slot {
     ($cls:ty) => {{
         #[allow(unknown_lints, non_local_definitions)]
         impl $cls {
-            #[allow(non_snake_case)]
+            #[allow(non_snake_case, unsafe_code)]
             unsafe extern "C" fn __pymethod___richcmp____(
                 slf: *mut $crate::ffi::PyObject,
                 other: *mut $crate::ffi::PyObject,

src/macros.rs

@@ -184,6 +184,7 @@ macro_rules! wrap_pymodule {
 #[macro_export]
 macro_rules! append_to_inittab {
     ($module:ident) => {
+        #[allow(unsafe_code)]
         unsafe {
             if $crate::ffi::Py_IsInitialized() != 0 {
                 ::std::panic!(

src/tests/hygiene/mod.rs

@@ -1,5 +1,6 @@
 #![no_implicit_prelude]
 #![allow(dead_code, unused_variables, clippy::unnecessary_wraps)]
+#![deny(unsafe_code)]
 
 // The modules in this test are used to check PyO3 macro expansion is hygienic. By locating the test
 // inside the crate the global `::pyo3` namespace is not available, so in combination with

src/types/mod.rs

@@ -133,6 +133,7 @@ macro_rules! pyobject_native_type_named (
             }
         }
 
+        #[allow(unsafe_code)]
         unsafe impl<$($generics,)*> $crate::AsPyPointer for $name {
             /// Gets the underlying FFI pointer, returns a borrowed pointer.
             #[inline]
@@ -160,6 +161,7 @@ macro_rules! pyobject_native_static_type_object(
 #[macro_export]
 macro_rules! pyobject_native_type_info(
     ($name:ty, $typeobject:expr, $module:expr $(, #checkfunction=$checkfunction:path)? $(;$generics:ident)*) => {
+        #[allow(unsafe_code)]
         unsafe impl<$($generics,)*> $crate::type_object::PyTypeInfo for $name {
             const NAME: &'static str = stringify!($name);
             const MODULE: ::std::option::Option<&'static str> = $module;