From 9d13c41ce61329cc85c7c3c67c859ffe2b0e6178 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@meta.com>
Date: Sat, 11 Jul 2026 08:21:01 -0700
Subject: [PATCH] Format null std::exception_ptr as "none"

Change the null exception_ptr representation from "nullptr" to "none" to
convey the "no exception" state more clearly, and update the test.
---
 include/fmt/std.h | 10 +++-------
 test/std-test.cc  |  2 +-
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/include/fmt/std.h b/include/fmt/std.h
index d606508b..207c9d35 100644
--- a/include/fmt/std.h
+++ b/include/fmt/std.h
@@ -651,16 +651,12 @@ struct formatter<
 
 template <> struct formatter<std::exception_ptr> : formatter<std::exception> {
   template <typename FormatContext>
-  auto format(const std::exception_ptr& ex_ptr, FormatContext& ctx) const
+  auto format(const std::exception_ptr& ep, FormatContext& ctx) const
       -> decltype(ctx.out()) {
-    if (!ex_ptr) {
-      return detail::write(ctx.out(), string_view("nullptr"));
-    }
-
+    if (!ep) return detail::write(ctx.out(), string_view("none"));
     try {
-      std::rethrow_exception(ex_ptr);
+      std::rethrow_exception(ep);
     } catch (const std::exception& e) {
-      // Reuses the base formatter<std::exception>::format behavior perfectly
       return formatter<std::exception>::format(e, ctx);
     } catch (...) {
       return detail::write(ctx.out(), string_view("unknown exception"));
diff --git a/test/std-test.cc b/test/std-test.cc
index b308fe38..d64ef956 100644
--- a/test/std-test.cc
+++ b/test/std-test.cc
@@ -415,7 +415,7 @@ TEST(std_test, exception_ptr) {
     p2 = std::current_exception();
   }
 
-  EXPECT_EQ(fmt::format("{}", p1), "nullptr");
+  EXPECT_EQ(fmt::format("{}", p1), "none");
   EXPECT_EQ(fmt::format("{}", p2), "My Exception");
 
 #if FMT_USE_RTTI