From 3cc32fdc8b01fd54fd415d8a76931bfdcc232b52 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@meta.com>
Date: Sun, 21 Jul 2024 08:00:34 -0700
Subject: [PATCH] Mark more formatters nonlocking

---
 include/fmt/base.h | 29 +++++++++++++++--------------
 test/base-test.cc  |  4 ++++
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/include/fmt/base.h b/include/fmt/base.h
index 6276494253dd..9336cd3fc0f9 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -1185,20 +1185,6 @@ namespace detail {
 template <typename T>
 struct is_back_insert_iterator<basic_appender<T>> : std::true_type {};
 
-template <typename T, typename Enable = void>
-struct locking : std::true_type {};
-template <typename T>
-struct locking<T, void_t<typename formatter<remove_cvref_t<T>>::nonlocking>>
-    : std::false_type {};
-
-template <typename T = int> FMT_CONSTEXPR inline auto is_locking() -> bool {
-  return locking<T>::value;
-}
-template <typename T1, typename T2, typename... Tail>
-FMT_CONSTEXPR inline auto is_locking() -> bool {
-  return locking<T1>::value || is_locking<T2, Tail...>();
-}
-
 // An optimized version of std::copy with the output value type (T).
 template <typename T, typename InputIt, typename OutputIt,
           FMT_ENABLE_IF(is_back_insert_iterator<OutputIt>::value)>
@@ -2074,6 +2060,21 @@ using sign_t = sign::type;
 
 namespace detail {
 
+template <typename T, typename Enable = void>
+struct locking : bool_constant<mapped_type_constant<T, format_context>::value ==
+                               type::custom_type> {};
+template <typename T>
+struct locking<T, void_t<typename formatter<remove_cvref_t<T>>::nonlocking>>
+    : std::false_type {};
+
+template <typename T = int> FMT_CONSTEXPR inline auto is_locking() -> bool {
+  return locking<T>::value;
+}
+template <typename T1, typename T2, typename... Tail>
+FMT_CONSTEXPR inline auto is_locking() -> bool {
+  return locking<T1>::value || is_locking<T2, Tail...>();
+}
+
 template <typename Char>
 using unsigned_char = typename conditional_t<std::is_integral<Char>::value,
                                              std::make_unsigned<Char>,
diff --git a/test/base-test.cc b/test/base-test.cc
index 765700368628..4e2164a4517c 100644
--- a/test/base-test.cc
+++ b/test/base-test.cc
@@ -92,6 +92,10 @@ TEST(string_view_test, compare) {
   check_op<std::greater_equal>();
 }
 
+TEST(base_test, is_locking) {
+  EXPECT_FALSE(fmt::detail::is_locking<const char (&)[3]>());
+}
+
 TEST(base_test, is_output_iterator) {
   EXPECT_TRUE((fmt::detail::is_output_iterator<char*, char>::value));
   EXPECT_FALSE((fmt::detail::is_output_iterator<const char*, char>::value));