From 6a9016ea600738ded2b90666d62b8f9bd241c00b Mon Sep 17 00:00:00 2001
From: Alexey Ochapov <alexez@alexez.com>
Date: Sun, 7 Mar 2021 17:44:36 +0300
Subject: [PATCH] fix `formatted_size` with "compiled format" as argument
 (#2161)

---
 include/fmt/compile.h | 5 ++++-
 include/fmt/core.h    | 6 +++---
 test/compile-test.cc  | 5 +++++
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/fmt/compile.h b/include/fmt/compile.h
index fa8eaeca2028..819d4abd9cac 100644
--- a/include/fmt/compile.h
+++ b/include/fmt/compile.h
@@ -928,7 +928,10 @@ format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n, const S&,
   return {it.base(), it.count()};
 }
 
-template <typename CompiledFormat, typename... Args>
+template <typename CompiledFormat, typename... Args,
+          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
+                                        CompiledFormat>::value ||
+                        detail::is_compiled_string<CompiledFormat>::value)>
 size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
   return format_to(detail::counting_iterator(), cf, args...).count();
 }
diff --git a/include/fmt/core.h b/include/fmt/core.h
index 7b2b2a435a0c..68cc7964fdd6 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -1865,11 +1865,11 @@ inline auto format_to_n(OutputIt out, size_t n, const S& format_str,
   Returns the number of characters in the output of
   ``format(format_str, args...)``.
  */
-template <typename... Args>
-inline size_t formatted_size(string_view format_str, Args&&... args) {
+template <typename S, typename... Args, typename Char = char_t<S>>
+inline size_t formatted_size(const S& format_str, Args&&... args) {
   const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
   detail::counting_buffer<> buf;
-  detail::vformat_to(buf, format_str, vargs);
+  detail::vformat_to(buf, to_string_view(format_str), vargs);
   return buf.count();
 }
 
diff --git a/test/compile-test.cc b/test/compile-test.cc
index d75166cc11af..2be2b884b7f4 100644
--- a/test/compile-test.cc
+++ b/test/compile-test.cc
@@ -261,6 +261,11 @@ TEST(CompileTest, FormatToNWithCompileMacro) {
   EXPECT_STREQ("2a", buffer);
 }
 
+TEST(CompileTest, FormattedSizeWithCompileMacro) {
+  EXPECT_EQ(2, fmt::formatted_size(FMT_COMPILE("{0}"), 42));
+  EXPECT_EQ(5, fmt::formatted_size(FMT_COMPILE("{0:<4.2f}"), 42.0));
+}
+
 TEST(CompileTest, TextAndArg) {
   EXPECT_EQ(">>>42<<<", fmt::format(FMT_COMPILE(">>>{}<<<"), 42));
   EXPECT_EQ("42!", fmt::format(FMT_COMPILE("{}!"), 42));