Mark Python::with_pool as safe on stable.

src/marker.rs

@@ -947,6 +947,9 @@ impl Python<'_> {
     /// it limits the closure to using the new GIL token at the cost of
     /// being unable to capture existing GIL-bound references.
     ///
+    /// Note that on stable Rust, this API suffers from the same the `SendWrapper` loophole
+    /// as [`allow_threads`][Self::allow_threads], c.f. the documentation of the [`Ungil`] trait,
+    ///
     /// # Examples
     ///
     /// ```rust
@@ -989,7 +992,6 @@ impl Python<'_> {
     ///     });
     /// });
     /// ```
-    #[cfg(feature = "nightly")]
     #[inline]
     pub fn with_pool<F, R>(&self, f: F) -> R
     where
@@ -1002,73 +1004,6 @@ impl Python<'_> {
 
         f(pool.python())
     }
-
-    /// Creates a scope using a new pool for managing PyO3's owned references.
-    ///
-    /// This is a safer alterantive to [`new_pool`][Self::new_pool] as
-    /// it limits the closure to using the new GIL token at the cost of
-    /// being unable to capture existing GIL-bound references.
-    ///
-    /// # Examples
-    ///
-    /// ```rust
-    /// # use pyo3::prelude::*;
-    /// Python::with_gil(|py| {
-    ///     // Some long-running process like a webserver, which never releases the GIL.
-    ///     loop {
-    ///         // Create a new scope, so that PyO3 can clear memory at the end of the loop.
-    ///         unsafe {
-    ///             py.with_pool(|py| {
-    ///                 // do stuff...
-    ///             });
-    ///         }
-    /// #       break;  // Exit the loop so that doctest terminates!
-    ///     }
-    /// });
-    /// ```
-    ///
-    /// The `Ungil` bound on the closure does prevent hanging on to existing GIL-bound references
-    ///
-    /// ```compile_fail
-    /// # use pyo3::prelude::*;
-    /// # use pyo3::types::PyString;
-    ///
-    /// Python::with_gil(|py| {
-    ///     let old_str = PyString::new(py, "a message from the past");
-    ///
-    ///     py.with_pool(|_py| {
-    ///         print!("{:?}", old_str);
-    ///     });
-    /// });
-    /// ```
-    ///
-    /// or continuing to use the old GIL token
-    ///
-    /// ```compile_fail
-    /// # use pyo3::prelude::*;
-    ///
-    /// Python::with_gil(|old_py| {
-    ///     old_py.with_pool(|_new_py| {
-    ///         let _none = old_py.None();
-    ///     });
-    /// });
-    /// ```
-    ///
-    /// # Safety
-    ///
-    /// However, due to the `SendWrapper` loophole describe in the documentation of the [`Ungil`] trait,
-    /// this is still an unsafe API. Usage that does not involve runtime checking of thread affinity
-    /// should be practically safe.
-    #[cfg(not(feature = "nightly"))]
-    #[inline]
-    pub unsafe fn with_pool<F, R>(&self, f: F) -> R
-    where
-        F: for<'py> FnOnce(Python<'py>) -> R + Ungil,
-    {
-        let pool = GILPool::new();
-
-        f(pool.python())
-    }
 }
 
 impl<'unbound> Python<'unbound> {