From 6a186bcd66bd2a808aae23588bcaf7861b95e638 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@fb.com>
Date: Wed, 21 Dec 2022 14:51:23 -0800
Subject: [PATCH] Localize FMT_USE_LOCAL_TIME

---
 include/fmt/chrono.h | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/include/fmt/chrono.h b/include/fmt/chrono.h
index 8a1e5a9b..a40576a1 100644
--- a/include/fmt/chrono.h
+++ b/include/fmt/chrono.h
@@ -462,7 +462,6 @@ auto write(OutputIt out, const std::tm& time, const std::locale& loc,
 
 FMT_MODULE_EXPORT_BEGIN
 
-#if FMT_USE_LOCAL_TIME
 /**
   Converts given time since epoch as ``std::time_t`` value into calendar time,
   expressed in local time. Unlike ``std::localtime``, this function is
@@ -504,10 +503,11 @@ inline std::tm localtime(std::time_t time) {
   return lt.tm_;
 }
 
-template<class Duration>
-inline std::tm localtime(
-    std::chrono::local_time<Duration> time_point) {
-  return localtime(std::chrono::system_clock::to_time_t(std::chrono::current_zone()->to_sys(time_point)));
+#if FMT_USE_LOCAL_TIME
+template <class Duration>
+inline auto localtime(std::chrono::local_time<Duration> time) -> std::tm {
+  return localtime(std::chrono::system_clock::to_time_t(
+      std::chrono::current_zone()->to_sys(time)));
 }
 #endif
 
@@ -2124,20 +2124,19 @@ struct formatter<std::chrono::time_point<std::chrono::system_clock, Duration>,
           epoch - std::chrono::duration_cast<std::chrono::seconds>(epoch));
 
       return formatter<std::tm, Char>::do_format(
-          gmtime(std::chrono::time_point_cast<std::chrono::seconds>(val)),
-          ctx, &subsecs);
+          gmtime(std::chrono::time_point_cast<std::chrono::seconds>(val)), ctx,
+          &subsecs);
     }
 
     return formatter<std::tm, Char>::format(
-        gmtime(std::chrono::time_point_cast<std::chrono::seconds>(val)),
-        ctx);
+        gmtime(std::chrono::time_point_cast<std::chrono::seconds>(val)), ctx);
   }
 };
 
 #if FMT_USE_LOCAL_TIME
 template <typename Char, typename Duration>
-struct formatter<std::chrono::local_time<Duration>,
-                 Char> : formatter<std::tm, Char> {
+struct formatter<std::chrono::local_time<Duration>, Char>
+    : formatter<std::tm, Char> {
   FMT_CONSTEXPR formatter() {
     basic_string_view<Char> default_specs =
         detail::string_literal<Char, '%', 'F', ' ', '%', 'T'>{};
@@ -2145,8 +2144,8 @@ struct formatter<std::chrono::local_time<Duration>,
   }
 
   template <typename FormatContext>
-  auto format(std::chrono::local_time<Duration> val,
-              FormatContext& ctx) const -> decltype(ctx.out()) {
+  auto format(std::chrono::local_time<Duration> val, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
     using period = typename Duration::period;
     if (period::num != 1 || period::den != 1 ||
         std::is_floating_point<typename Duration::rep>::value) {