From 2e35470cffc47903dd47b7e68c7acf4302fd7057 Mon Sep 17 00:00:00 2001
From: Sam Gross <colesbury@gmail.com>
Date: Wed, 26 Jun 2024 15:46:46 -0400
Subject: [PATCH 1/3] fix: use manual padding of instance_map_shard (#5200)

* Use manual padding of instance_map_shard.

The alignas(64) specifier requires aligned allocation, which is not
available on macOS when targeting versions before 10.14.

* Add 'see #5200'

* Update include/pybind11/detail/internals.h

* Update include/pybind11/detail/internals.h

---------

Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>
---
 include/pybind11/detail/internals.h | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/include/pybind11/detail/internals.h b/include/pybind11/detail/internals.h
index 92a851602d..e61c1687fc 100644
--- a/include/pybind11/detail/internals.h
+++ b/include/pybind11/detail/internals.h
@@ -148,18 +148,14 @@ struct override_hash {
 
 using instance_map = std::unordered_multimap<const void *, instance *>;
 
-// ignore: structure was padded due to alignment specifier
-PYBIND11_WARNING_PUSH
-PYBIND11_WARNING_DISABLE_MSVC(4324)
-
 // Instance map shards are used to reduce mutex contention in free-threaded Python.
-struct alignas(64) instance_map_shard {
+struct instance_map_shard {
     std::mutex mutex;
     instance_map registered_instances;
+    // alignas(64) would be better, but causes compile errors in macOS before 10.14 (see #5200)
+    char padding[64 - (sizeof(std::mutex) + sizeof(instance_map)) % 64];
 };
 
-PYBIND11_WARNING_POP
-
 /// Internal data structure used to track registered instances and types.
 /// Whenever binary incompatible changes are made to this structure,
 /// `PYBIND11_INTERNALS_VERSION` must be incremented.

From 4bd538a40a45803b24f95ef4fb3de5d773e2d426 Mon Sep 17 00:00:00 2001
From: Michael Carlstrom <rmc@carlstrom.com>
Date: Wed, 26 Jun 2024 16:34:06 -0400
Subject: [PATCH 2/3] feat(types): add support for Typing.Callable Special Case
 (#5202)

* Add special case

* linty
---
 include/pybind11/typing.h | 8 ++++++++
 tests/test_pytypes.cpp    | 1 +
 tests/test_pytypes.py     | 7 +++++++
 3 files changed, 16 insertions(+)

diff --git a/include/pybind11/typing.h b/include/pybind11/typing.h
index cf70b739ed..1442cdc7f1 100644
--- a/include/pybind11/typing.h
+++ b/include/pybind11/typing.h
@@ -177,6 +177,14 @@ struct handle_type_name<typing::Callable<Return(Args...)>> {
           + const_name("], ") + make_caster<retval_type>::name + const_name("]");
 };
 
+template <typename Return>
+struct handle_type_name<typing::Callable<Return(ellipsis)>> {
+    // PEP 484 specifies this syntax for defining only return types of callables
+    using retval_type = conditional_t<std::is_same<Return, void>::value, void_type, Return>;
+    static constexpr auto name
+        = const_name("Callable[..., ") + make_caster<retval_type>::name + const_name("]");
+};
+
 template <typename T>
 struct handle_type_name<typing::Type<T>> {
     static constexpr auto name = const_name("type[") + make_caster<T>::name + const_name("]");
diff --git a/tests/test_pytypes.cpp b/tests/test_pytypes.cpp
index 6b347894b0..7c30978cea 100644
--- a/tests/test_pytypes.cpp
+++ b/tests/test_pytypes.cpp
@@ -865,6 +865,7 @@ TEST_SUBMODULE(pytypes, m) {
     m.def("annotate_fn",
           [](const py::typing::Callable<int(py::typing::List<py::str>, py::str)> &) {});
 
+    m.def("annotate_fn_only_return", [](const py::typing::Callable<int(py::ellipsis)> &) {});
     m.def("annotate_type", [](const py::typing::Type<int> &t) -> py::type { return t; });
 
     m.def("annotate_union",
diff --git a/tests/test_pytypes.py b/tests/test_pytypes.py
index 92a3a36bf4..30931e0b9a 100644
--- a/tests/test_pytypes.py
+++ b/tests/test_pytypes.py
@@ -959,6 +959,13 @@ def test_fn_annotations(doc):
     )
 
 
+def test_fn_return_only(doc):
+    assert (
+        doc(m.annotate_fn_only_return)
+        == "annotate_fn_only_return(arg0: Callable[..., int]) -> None"
+    )
+
+
 def test_type_annotation(doc):
     assert doc(m.annotate_type) == "annotate_type(arg0: type[int]) -> type"
 

From 57287b578d58af016cd571f6eacee19300d37f2d Mon Sep 17 00:00:00 2001
From: Henry Schreiner <HenrySchreinerIII@gmail.com>
Date: Wed, 26 Jun 2024 18:14:17 -0400
Subject: [PATCH 3/3] docs: prepare for 2.13.1 (#5203)

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>
---
 docs/changelog.rst | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 7135e65311..ab6c713c16 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -15,6 +15,20 @@ IN DEVELOPMENT
 
 Changes will be summarized here periodically.
 
+Version 2.13.1 (June 26, 2024)
+------------------------------
+
+New Features:
+
+* Add support for ``Typing.Callable[..., T]``.
+  `#5202 <https://github.com/pybind/pybind11/pull/5202>`_
+
+Bug fixes:
+
+* Avoid aligned allocation in free-threaded build in order to support macOS
+  versions before 10.14.
+  `#5200 <https://github.com/pybind/pybind11/pull/5200>`_
+
 Version 2.13.0 (June 25, 2024)
 ------------------------------