From 6709abba934e968d31c24f20c132c67a6f424a6a Mon Sep 17 00:00:00 2001
From: Tamaki Nishino <otamachan@gmail.com>
Date: Wed, 14 Apr 2021 08:53:56 +0900
Subject: [PATCH] Allow function pointer extraction from overloaded functions
 (#2944)

* Add a failure test for overloaded functions

* Allow function pointer extraction from overloaded functions
---
 include/pybind11/functional.h | 16 +++++++++++-----
 tests/test_callbacks.cpp      |  2 ++
 tests/test_callbacks.py       |  4 ++++
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/include/pybind11/functional.h b/include/pybind11/functional.h
index 92c17dc22..aee9be4e4 100644
--- a/include/pybind11/functional.h
+++ b/include/pybind11/functional.h
@@ -46,11 +46,17 @@ public:
             auto c = reinterpret_borrow<capsule>(PyCFunction_GET_SELF(cfunc.ptr()));
             auto rec = (function_record *) c;
 
-            if (rec && rec->is_stateless &&
-                    same_type(typeid(function_type), *reinterpret_cast<const std::type_info *>(rec->data[1]))) {
-                struct capture { function_type f; };
-                value = ((capture *) &rec->data)->f;
-                return true;
+            while (rec != nullptr) {
+                if (rec->is_stateless
+                    && same_type(typeid(function_type),
+                                 *reinterpret_cast<const std::type_info *>(rec->data[1]))) {
+                    struct capture {
+                        function_type f;
+                    };
+                    value = ((capture *) &rec->data)->f;
+                    return true;
+                }
+                rec = rec->next;
             }
         }
 
diff --git a/tests/test_callbacks.cpp b/tests/test_callbacks.cpp
index 61bc3a8f0..33927f5c3 100644
--- a/tests/test_callbacks.cpp
+++ b/tests/test_callbacks.cpp
@@ -97,6 +97,8 @@ TEST_SUBMODULE(callbacks, m) {
     // test_cpp_function_roundtrip
     /* Test if passing a function pointer from C++ -> Python -> C++ yields the original pointer */
     m.def("dummy_function", &dummy_function);
+    m.def("dummy_function_overloaded", [](int i, int j) { return i + j; });
+    m.def("dummy_function_overloaded", &dummy_function);
     m.def("dummy_function2", [](int i, int j) { return i + j; });
     m.def("roundtrip", [](std::function<int(int)> f, bool expect_none = false) {
         if (expect_none && f)
diff --git a/tests/test_callbacks.py b/tests/test_callbacks.py
index cec68bda5..352661430 100644
--- a/tests/test_callbacks.py
+++ b/tests/test_callbacks.py
@@ -93,6 +93,10 @@ def test_cpp_function_roundtrip():
         m.test_dummy_function(m.roundtrip(m.dummy_function))
         == "matches dummy_function: eval(1) = 2"
     )
+    assert (
+        m.test_dummy_function(m.dummy_function_overloaded)
+        == "matches dummy_function: eval(1) = 2"
+    )
     assert m.roundtrip(None, expect_none=True) is None
     assert (
         m.test_dummy_function(lambda x: x + 2)