From c9ce487d6f24c4c1ebd42ee29f624b0220f35e35 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Fri, 29 Nov 2024 23:44:53 -0800
Subject: [PATCH] 1. Add
 `PYBIND11_WARNING_DISABLE_CLANG("-Wgnu-zero-variadic-macro-arguments")` near
 the top of pybind11/pybind11.h; 2. Change `PYBIND11_DECLARE_HOLDER_TYPE`
 macro to side-step the only remaining clang warning-as-error (this is still
 needed even for clang 18).

Alternatively the warning suppression could be moved into pybind11/cast.h, but this commit limits the warning suppression to smaller scope within include/pybind11.
---
 include/pybind11/cast.h     | 10 ++++++----
 include/pybind11/pybind11.h |  6 ++++++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index 2ae25c2ebf..7ae9fa037f 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -863,18 +863,20 @@ using type_caster_holder = conditional_t<is_copy_constructible<holder_type>::val
                                          copyable_holder_caster<type, holder_type>,
                                          move_only_holder_caster<type, holder_type>>;
 
-template <typename T, bool Value = false>
-struct always_construct_holder {
+template <bool Value = false>
+struct always_construct_holder_value {
     static constexpr bool value = Value;
 };
 
+template <typename T, bool Value = false>
+struct always_construct_holder : always_construct_holder_value<Value> {};
+
 /// Create a specialization for custom holder types (silently ignores std::shared_ptr)
 #define PYBIND11_DECLARE_HOLDER_TYPE(type, holder_type, ...)                                      \
     PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)                                                  \
     namespace detail {                                                                            \
     template <typename type>                                                                      \
-    struct always_construct_holder<holder_type> : always_construct_holder<void, ##__VA_ARGS__> {  \
-    };                                                                                            \
+    struct always_construct_holder<holder_type> : always_construct_holder_value<__VA_ARGS__> {};  \
     template <typename type>                                                                      \
     class type_caster<holder_type, enable_if_t<!is_shared_ptr<holder_type>::value>>               \
         : public type_caster_holder<type, holder_type> {};                                        \
diff --git a/include/pybind11/pybind11.h b/include/pybind11/pybind11.h
index fe8384e57f..721808701f 100644
--- a/include/pybind11/pybind11.h
+++ b/include/pybind11/pybind11.h
@@ -26,6 +26,12 @@
 #include <utility>
 #include <vector>
 
+// See PR #5448. This warning suppression is needed for the PYBIND11_OVERRIDE macro family.
+// NOTE that this is NOT embedded in a push/pop pair because that is very difficult to achieve.
+#if defined(__clang_major__) && __clang_major__ < 14
+PYBIND11_WARNING_DISABLE_CLANG("-Wgnu-zero-variadic-macro-arguments")
+#endif
+
 #if defined(__cpp_lib_launder) && !(defined(_MSC_VER) && (_MSC_VER < 1914))
 #    define PYBIND11_STD_LAUNDER std::launder
 #    define PYBIND11_HAS_STD_LAUNDER 1