From 2b364d319059923f0d94cc705f35e77680c55ccb Mon Sep 17 00:00:00 2001
From: David Hewitt <mail@davidhewitt.dev>
Date: Fri, 22 Nov 2024 16:31:22 +0000
Subject: [PATCH] support 3.13t free-threaded python

---
 .github/workflows/ci.yml |  3 ++-
 CHANGELOG.md             |  1 +
 src/datetime.rs          | 12 ++++++------
 src/strings.rs           | 11 +++++------
 4 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f4e801413..f6c84b891 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -39,6 +39,7 @@ jobs:
             "3.11",
             "3.12",
             "3.13",
+            "3.13t",
             "pypy-3.9",
             "pypy-3.10",
           ]
@@ -108,7 +109,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+        uses: Quansight-Labs/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
           architecture: ${{ matrix.platform.python-architecture }}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9b748cf6f..65fd124a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
     - removed the `gil-refs` feature
     - reintroduced function names without `_bound` suffix + deprecating the old names
     - switched to `IntoPyObject` as trait bound
+  - Support Python 3.13t "free-threaded" Python. ([#471](https://github.com/PyO3/rust-numpy/pull/471)
 
 - v0.22.1
   - Fix building on 32-bit Windows. ([#463](https://github.com/PyO3/rust-numpy/pull/463))
diff --git a/src/datetime.rs b/src/datetime.rs
index 3eef346d8..b43a2e062 100644
--- a/src/datetime.rs
+++ b/src/datetime.rs
@@ -54,13 +54,13 @@
 //! [scalars-datetime64]: https://numpy.org/doc/stable/reference/arrays.scalars.html#numpy.datetime64
 //! [scalars-timedelta64]: https://numpy.org/doc/stable/reference/arrays.scalars.html#numpy.timedelta64
 
-use std::cell::RefCell;
 use std::collections::hash_map::Entry;
 use std::fmt;
 use std::hash::Hash;
 use std::marker::PhantomData;
+use std::sync::Mutex;
 
-use pyo3::{sync::GILProtected, Bound, Py, Python};
+use pyo3::{Bound, Py, Python};
 use rustc_hash::FxHashMap;
 
 use crate::dtype::{clone_methods_impl, Element, PyArrayDescr, PyArrayDescrMethods};
@@ -209,8 +209,7 @@ impl<U: Unit> fmt::Debug for Timedelta<U> {
 
 struct TypeDescriptors {
     npy_type: NPY_TYPES,
-    #[allow(clippy::type_complexity)]
-    dtypes: GILProtected<RefCell<Option<FxHashMap<NPY_DATETIMEUNIT, Py<PyArrayDescr>>>>>,
+    dtypes: Mutex<Option<FxHashMap<NPY_DATETIMEUNIT, Py<PyArrayDescr>>>>,
 }
 
 impl TypeDescriptors {
@@ -218,13 +217,14 @@ impl TypeDescriptors {
     const unsafe fn new(npy_type: NPY_TYPES) -> Self {
         Self {
             npy_type,
-            dtypes: GILProtected::new(RefCell::new(None)),
+            dtypes: Mutex::new(None),
         }
     }
 
     #[allow(clippy::wrong_self_convention)]
     fn from_unit<'py>(&self, py: Python<'py>, unit: NPY_DATETIMEUNIT) -> Bound<'py, PyArrayDescr> {
-        let mut dtypes = self.dtypes.get(py).borrow_mut();
+        // FIXME probably a deadlock risk here due to the GIL? Might need MutexExt trait in PyO3
+        let mut dtypes = self.dtypes.lock().expect("dtype cache poisoned");
 
         let dtype = match dtypes.get_or_insert_with(Default::default).entry(unit) {
             Entry::Occupied(entry) => entry.into_mut(),
diff --git a/src/strings.rs b/src/strings.rs
index 067327865..e2a05b95e 100644
--- a/src/strings.rs
+++ b/src/strings.rs
@@ -3,16 +3,15 @@
 //! [ascii]: https://numpy.org/doc/stable/reference/c-api/dtype.html#c.NPY_STRING
 //! [ucs4]: https://numpy.org/doc/stable/reference/c-api/dtype.html#c.NPY_UNICODE
 
-use std::cell::RefCell;
 use std::collections::hash_map::Entry;
 use std::fmt;
 use std::mem::size_of;
 use std::os::raw::c_char;
 use std::str;
+use std::sync::Mutex;
 
 use pyo3::{
     ffi::{Py_UCS1, Py_UCS4},
-    sync::GILProtected,
     Bound, Py, Python,
 };
 use rustc_hash::FxHashMap;
@@ -160,14 +159,13 @@ unsafe impl<const N: usize> Element for PyFixedUnicode<N> {
 }
 
 struct TypeDescriptors {
-    #[allow(clippy::type_complexity)]
-    dtypes: GILProtected<RefCell<Option<FxHashMap<usize, Py<PyArrayDescr>>>>>,
+    dtypes: Mutex<Option<FxHashMap<usize, Py<PyArrayDescr>>>>,
 }
 
 impl TypeDescriptors {
     const fn new() -> Self {
         Self {
-            dtypes: GILProtected::new(RefCell::new(None)),
+            dtypes: Mutex::new(None),
         }
     }
 
@@ -180,7 +178,8 @@ impl TypeDescriptors {
         byteorder: c_char,
         size: usize,
     ) -> Bound<'py, PyArrayDescr> {
-        let mut dtypes = self.dtypes.get(py).borrow_mut();
+        // FIXME probably a deadlock risk here due to the GIL? Might need MutexExt trait in PyO3
+        let mut dtypes = self.dtypes.lock().expect("dtype cache poisoned");
 
         let dtype = match dtypes.get_or_insert_with(Default::default).entry(size) {
             Entry::Occupied(entry) => entry.into_mut(),