From d4248623196991b434b8cb7689affb83fd04aca2 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@meta.com>
Date: Mon, 7 Aug 2023 13:56:53 -0700
Subject: [PATCH] Fix fixed precision handling during rounding in long double

---
 include/fmt/format.h | 3 ++-
 test/format-test.cc  | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index 6cd2c355..e5bd8b11 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3178,7 +3178,8 @@ FMT_CONSTEXPR20 inline void format_dragon(basic_fp<uint128_t> value,
       }
       if (buf[0] == overflow) {
         buf[0] = '1';
-        ++exp10;
+        if ((flags & dragon::fixed) != 0) buf.push_back('0');
+        else ++exp10;
       }
       return;
     }
diff --git a/test/format-test.cc b/test/format-test.cc
index 52ac2caf..d148e743 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1472,6 +1472,7 @@ TEST(format_test, format_long_double) {
   EXPECT_EQ("0", fmt::format("{0:}", 0.0l));
   EXPECT_EQ("0.000000", fmt::format("{0:f}", 0.0l));
   EXPECT_EQ("0.0", fmt::format("{:.1f}", 0.000000001l));
+  EXPECT_EQ("0.10", fmt::format("{:.2f}", 0.099l));
   EXPECT_EQ("392.65", fmt::format("{0:}", 392.65l));
   EXPECT_EQ("392.65", fmt::format("{0:g}", 392.65l));
   EXPECT_EQ("392.65", fmt::format("{0:G}", 392.65l));