Support pickling slot wrapper descriptors (#9037)

Extract wrapper descriptor reduction from #8954 for Python 3.14. Reduce to getattr on the defining class and cover direct reduction plus one roundtrip in the existing pickle snippet. Preserve canonical expected failures for unrelated staticmethod descriptor behavior.

Assisted-by: OpenAI Codex:model identifier unavailable

crates/vm/src/builtins/descriptor.rs

@@ -2062,6 +2062,16 @@ impl Callable for PyWrapper {
     flags(DISALLOW_INSTANTIATION)
 )]
 impl Py<PyWrapper> {
+    #[pymethod]
+    fn __reduce__(&self, vm: &VirtualMachine) -> PyResult {
+        let getattr = vm.builtins.get_attr("getattr", vm)?;
+        let args = vm.ctx.new_tuple(vec![
+            self.typ.to_owned().into(),
+            self.name.to_owned().into(),
+        ]);
+        Ok(vm.ctx.new_tuple(vec![getattr, args.into()]).into())
+    }
+
     #[pygetset]
     fn __qualname__(&self) -> String {
         format!("{}.{}", self.typ.name(), self.name)

extra_tests/snippets/stdlib_pickle.py

@@ -9,3 +9,7 @@ memo = unpickler.memo.copy()
 assert list(memo) == [1, 7]
 assert memo[1] is left
 assert memo[7] is left
+
+# Slot wrapper descriptors reduce to lookup on their defining class.
+assert object.__str__.__reduce__() == (getattr, (object, "__str__"))
+assert _pickle.loads(_pickle.dumps(object.__str__)) is object.__str__