From f1e2e55bdabfcab0506d8bd8d970dd47aba829be Mon Sep 17 00:00:00 2001
From: Xiaofei Wang <6218006+wangxf123456@users.noreply.github.com>
Date: Thu, 3 Aug 2023 18:33:16 -0700
Subject: [PATCH] [smart_holder] Make smart holder type caster of `unique_ptr`
 accept `automatic_reference` (#4775)

* Also accept automatic_reference

* Add a test case

* Remove the test case

* Add another test case

* Fix test case
---
 include/pybind11/detail/smart_holder_type_casters.h | 1 +
 tests/test_class_sh_basic.cpp                       | 6 ++++++
 tests/test_class_sh_basic.py                        | 4 ++++
 3 files changed, 11 insertions(+)

diff --git a/include/pybind11/detail/smart_holder_type_casters.h b/include/pybind11/detail/smart_holder_type_casters.h
index 67d7c4f13..bd9483a02 100644
--- a/include/pybind11/detail/smart_holder_type_casters.h
+++ b/include/pybind11/detail/smart_holder_type_casters.h
@@ -965,6 +965,7 @@ struct smart_holder_type_caster<std::unique_ptr<T, D>> : smart_holder_type_caste
 
     static handle cast(std::unique_ptr<T, D> &&src, return_value_policy policy, handle parent) {
         if (policy != return_value_policy::automatic
+            && policy != return_value_policy::automatic_reference
             && policy != return_value_policy::reference_internal
             && policy != return_value_policy::move
             && policy != return_value_policy::_clif_automatic) {
diff --git a/tests/test_class_sh_basic.cpp b/tests/test_class_sh_basic.cpp
index 502f48a2c..7582cfa04 100644
--- a/tests/test_class_sh_basic.cpp
+++ b/tests/test_class_sh_basic.cpp
@@ -160,6 +160,12 @@ TEST_SUBMODULE(class_sh_basic, m) {
     m.def("args_shared_ptr_const", [](std::shared_ptr<atyp const> p) { return p; });
     m.def("args_unique_ptr", [](std::unique_ptr<atyp> p) { return p; });
     m.def("args_unique_ptr_const", [](std::unique_ptr<atyp const> p) { return p; });
+
+    // Make sure unique_ptr type caster accept automatic_reference return value policy.
+    m.def(
+        "rtrn_uq_automatic_reference",
+        []() { return std::unique_ptr<atyp>(new atyp("rtrn_uq_automatic_reference")); },
+        pybind11::return_value_policy::automatic_reference);
 }
 
 } // namespace class_sh_basic
diff --git a/tests/test_class_sh_basic.py b/tests/test_class_sh_basic.py
index 95460d9dc..268e79398 100644
--- a/tests/test_class_sh_basic.py
+++ b/tests/test_class_sh_basic.py
@@ -181,3 +181,7 @@ def test_function_signatures(doc):
         doc(m.args_unique_ptr_const)
         == "args_unique_ptr_const(arg0: m.class_sh_basic.atyp) -> m.class_sh_basic.atyp"
     )
+
+
+def test_unique_ptr_return_value_policy_automatic_reference():
+    assert m.get_mtxt(m.rtrn_uq_automatic_reference()) == "rtrn_uq_automatic_reference"