Misc cleanups (PyO3#5970)

* remove rustc-check-cfg check

* simplify cfg'd diagnostic attribute

* Fix pyproto comment

* Use poll_fn

* remove unused doc imports

* Only emit note on < 3.12

* Fix ui test

* Eanble abi3_inheritance test again

Author: mejrs

pyo3-build-config/src/lib.rs

@@ -257,11 +257,6 @@ pub fn print_feature_cfgs() {
 /// - <https://doc.rust-lang.org/nightly/cargo/reference/build-scripts.html#rustc-check-cfg>
 #[doc(hidden)]
 pub fn print_expected_cfgs() {
-    if rustc_minor_version().is_some_and(|version| version < 80) {
-        // rustc 1.80.0 stabilized `rustc-check-cfg` feature, don't emit before
-        return;
-    }
-
     println!("cargo:rustc-check-cfg=cfg(Py_LIMITED_API)");
     println!("cargo:rustc-check-cfg=cfg(Py_GIL_DISABLED)");
     println!("cargo:rustc-check-cfg=cfg(PyPy)");

src/coroutine/cancel.rs

@@ -1,6 +1,5 @@
 use crate::{Py, PyAny};
-use std::future::Future;
-use std::pin::Pin;
+use std::future::poll_fn;
 use std::sync::{Arc, Mutex};
 use std::task::{Context, Poll, Waker};
 
@@ -44,7 +43,7 @@ impl CancelHandle {
 
     /// Retrieve the exception thrown in the associated coroutine.
     pub async fn cancelled(&mut self) -> Py<PyAny> {
-        Cancelled(self).await
+        poll_fn(|cx| self.poll_cancelled(cx)).await
     }
 
     #[doc(hidden)]
@@ -53,16 +52,6 @@ impl CancelHandle {
     }
 }
 
-// Because `poll_fn` is not available in MSRV
-struct Cancelled<'a>(&'a mut CancelHandle);
-
-impl Future for Cancelled<'_> {
-    type Output = Py<PyAny>;
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        self.0.poll_cancelled(cx)
-    }
-}
-
 #[doc(hidden)]
 pub struct ThrowCallback(Arc<Mutex<Inner>>);
 

src/impl_/callback.rs

@@ -131,7 +131,7 @@ impl IntoPyCallbackOutput<'_, ffi::Py_ssize_t> for usize {
     }
 }
 
-// Converters needed for `#[pyproto]` implementations
+// Conversion traits needed by pyo3's macros
 
 impl IntoPyCallbackOutput<'_, bool> for bool {
     #[inline]

src/impl_/pyclass.rs

@@ -1060,21 +1060,15 @@ impl<T> PyClassThreadChecker<T> for ThreadCheckerImpl {
 }
 
 /// Trait denoting that this class is suitable to be used as a base type for PyClass.
-#[cfg_attr(
-    Py_LIMITED_API,
-    diagnostic::on_unimplemented(
-        message = "pyclass `{Self}` cannot be subclassed",
-        label = "required for `#[pyclass(extends={Self})]`",
-        note = "`{Self}` must have `#[pyclass(subclass)]` to be eligible for subclassing",
-        note = "with the `abi3` feature enabled, PyO3 does not support subclassing native types",
-    )
+#[diagnostic::on_unimplemented(
+    message = "pyclass `{Self}` cannot be subclassed",
+    label = "required for `#[pyclass(extends={Self})]`",
+    note = "`{Self}` must have `#[pyclass(subclass)]` to be eligible for subclassing"
 )]
 #[cfg_attr(
-    not(Py_LIMITED_API),
+    all(Py_LIMITED_API, not(Py_3_12)),
     diagnostic::on_unimplemented(
-        message = "pyclass `{Self}` cannot be subclassed",
-        label = "required for `#[pyclass(extends={Self})]`",
-        note = "`{Self}` must have `#[pyclass(subclass)]` to be eligible for subclassing",
+        note = "subclassing native types requires Python >= 3.12 when using the `abi3` feature",
     )
 )]
 pub trait PyClassBaseType: Sized {

src/lib.rs

@@ -249,7 +249,6 @@
 //! ```rust
 //! use pyo3::prelude::*;
 //! use pyo3::types::IntoPyDict;
-//! use pyo3::ffi::c_str;
 //!
 //! fn main() -> PyResult<()> {
 //!     Python::attach(|py| {

src/marker.rs

@@ -393,7 +393,6 @@ impl Python<'_> {
     ///
     /// ```
     /// use pyo3::prelude::*;
-    /// use pyo3::ffi::c_str;
     ///
     /// # fn main() -> PyResult<()> {
     /// Python::attach(|py| -> PyResult<()> {
@@ -581,7 +580,6 @@ impl<'py> Python<'py> {
     ///
     /// ```
     /// # use pyo3::prelude::*;
-    /// # use pyo3::ffi::c_str;
     /// # Python::attach(|py| {
     /// let result = py.eval(c"[i * 10 for i in range(5)]", None, None).unwrap();
     /// let res: Vec<i64> = result.extract().unwrap();
@@ -611,7 +609,6 @@ impl<'py> Python<'py> {
     /// use pyo3::{
     ///     prelude::*,
     ///     types::{PyBytes, PyDict},
-    ///     ffi::c_str,
     /// };
     /// Python::attach(|py| {
     ///     let locals = PyDict::new(py);

src/types/iterator.rs

@@ -15,7 +15,6 @@ use crate::{ffi, Bound, Py, PyAny, PyErr, PyResult};
 ///
 /// ```rust
 /// use pyo3::prelude::*;
-/// use pyo3::ffi::c_str;
 ///
 /// # fn main() -> PyResult<()> {
 /// Python::attach(|py| -> PyResult<()> {

src/types/mod.rs

@@ -60,7 +60,6 @@ pub use self::weakref::{PyWeakref, PyWeakrefMethods, PyWeakrefProxy, PyWeakrefRe
 /// ```rust
 /// use pyo3::prelude::*;
 /// use pyo3::types::PyDict;
-/// use pyo3::ffi::c_str;
 ///
 /// # pub fn main() -> PyResult<()> {
 /// Python::attach(|py| {

src/types/module.rs

@@ -142,7 +142,6 @@ impl PyModule {
     ///
     /// ```rust
     /// use pyo3::prelude::*;
-    /// use pyo3::ffi::c_str;
     /// use std::ffi::CString;
     ///
     /// # fn main() -> PyResult<()> {

src/types/weakref/proxy.rs

@@ -108,7 +108,6 @@ impl PyWeakrefProxy {
     )]
     /// use pyo3::prelude::*;
     /// use pyo3::types::PyWeakrefProxy;
-    /// use pyo3::ffi::c_str;
     ///
     /// #[pyclass(weakref)]
     /// struct Foo { /* fields omitted */ }