Update version

In situations where `using namespace std;` is used, compiler warnings
can be generated because of local variables named `ignore`. This renames
those variables to something else to address the name conflict.

.github/workflows/cifuzz.yml

@@ -25,7 +25,7 @@ jobs:
         language: c++
 
     - name: Upload crash
-      uses: actions/upload-artifact@50769540e7f4bd5e21e526ee35c689e35e0d6874 # v4.4.0
+      uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v4.6.0
       if: failure() && steps.build.outcome == 'success'
       with:
         name: artifacts

.github/workflows/scorecard.yml

@@ -52,7 +52,7 @@ jobs:
       # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
       # format to the repository Actions tab.
       - name: "Upload artifact"
-        uses: actions/upload-artifact@50769540e7f4bd5e21e526ee35c689e35e0d6874 # v4.4.0
+        uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v4.6.0
         with:
           name: SARIF file
           path: results.sarif
@@ -60,6 +60,6 @@ jobs:
 
       # Upload the results to GitHub's code scanning dashboard.
       - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@662472033e021d55d94146f66f6058822b0b39fd # v3.27.0
+        uses: github/codeql-action/upload-sarif@dd746615b3b9d728a6a37ca2045b68ca76d4841a # v3.28.8
         with:
           sarif_file: results.sarif

.gitignore

@@ -3,6 +3,7 @@
 *.xcodeproj
 *~
 .vscode/
+.vs/
 /CMakeScripts
 /Testing
 /_CPack_Packages

CMakeLists.txt

@@ -27,7 +27,13 @@ endfunction()
 # DEPRECATED! Should be merged into add_module_library.
 function(enable_module target)
   if (MSVC)
-    set(BMI ${CMAKE_CURRENT_BINARY_DIR}/${target}.ifc)
+    if(CMAKE_GENERATOR STREQUAL "Ninja")
+      # Ninja dyndep expects the .ifc output to be located in a specific relative path
+      file(RELATIVE_PATH BMI_DIR "${CMAKE_BINARY_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${target}.dir")
+    else()
+      set(BMI_DIR "${CMAKE_CURRENT_BINARY_DIR}")
+    endif()
+    file(TO_NATIVE_PATH "${BMI_DIR}/${target}.ifc" BMI)
     target_compile_options(${target}
       PRIVATE /interface /ifcOutput ${BMI}
       INTERFACE /reference fmt=${BMI})
@@ -69,8 +75,6 @@ function(add_module_library name)
     target_compile_options(${name} PUBLIC -fmodules-ts)
   endif ()
 
-  target_compile_definitions(${name} PRIVATE FMT_MODULE)
-
   if (FMT_USE_CMAKE_MODULES)
     target_sources(${name} PUBLIC FILE_SET fmt TYPE CXX_MODULES
                    FILES ${sources})
@@ -295,6 +299,7 @@ function(add_headers VAR)
 endfunction()
 
 # Define the fmt library, its includes and the needed defines.
+set(FMT_HEADERS)
 add_headers(FMT_HEADERS args.h base.h chrono.h color.h compile.h core.h format.h
                         format-inl.h os.h ostream.h printf.h ranges.h std.h
                         xchar.h)

ChangeLog.md

@@ -1,3 +1,62 @@
+# 11.1.4 - 2025-02-26
+
+- Fixed ABI compatibility with earlier 11.x versions on Windows
+  (https://github.com/fmtlib/fmt/issues/4359).
+
+- Improved the logic of switching between fixed and exponential format for
+  `float` (https://github.com/fmtlib/fmt/issues/3649).
+
+- Moved `is_compiled_string` to the public API
+  (https://github.com/fmtlib/fmt/issues/4342). Thanks @SwooshyCueb.
+
+- Simplified implementation of `operator""_cf`
+  (https://github.com/fmtlib/fmt/pull/4349). Thanks @LocalSpook.
+
+- Fixed `__builtin_strlen` detection (https://github.com/fmtlib/fmt/pull/4329).
+  Thanks @LocalSpook.
+
+- Fixed handling of BMI paths with the Ninja generator
+  (https://github.com/fmtlib/fmt/pull/4344). Thanks @tkhyn.
+
+- Fixed gcc 8.3 compile errors (https://github.com/fmtlib/fmt/issues/4331,
+  https://github.com/fmtlib/fmt/pull/4336). Thanks @sergiud.
+
+- Fixed a bogus MSVC warning (https://github.com/fmtlib/fmt/pull/4356).
+  Thanks @dinomight.
+
+# 11.1.3 - 2025-01-25
+
+- Fixed compilation on GCC 9.4 (https://github.com/fmtlib/fmt/issues/4313).
+
+- Worked around an internal compiler error when using C++20 modules with GCC
+  14.2 and earlier (https://github.com/fmtlib/fmt/issues/4295).
+
+- Worked around a bug in GCC 6 (https://github.com/fmtlib/fmt/issues/4318).
+
+- Fixed an issue caused by instantiating `formatter<const T>`
+  (https://github.com/fmtlib/fmt/issues/4303,
+  https://github.com/fmtlib/fmt/pull/4325). Thanks @timsong-cpp.
+
+- Fixed formatting into `std::ostreambuf_iterator` when using format string
+  compilation (https://github.com/fmtlib/fmt/issues/4309,
+  https://github.com/fmtlib/fmt/pull/4312). Thanks @phprus.
+
+- Restored a constraint on the map formatter so that it correctly reports as
+  unformattable when the element is (https://github.com/fmtlib/fmt/pull/4326).
+  Thanks @timsong-cpp.
+
+- Reduced the size of format specs (https://github.com/fmtlib/fmt/issues/4298).
+
+- Readded `args()` to `fmt::format_context`
+  (https://github.com/fmtlib/fmt/issues/4307,
+  https://github.com/fmtlib/fmt/pull/4310). Thanks @Erroneous1.
+
+- Fixed a bogus MSVC warning (https://github.com/fmtlib/fmt/issues/4314,
+  https://github.com/fmtlib/fmt/pull/4322). Thanks @ZehMatt.
+
+- Fixed a pedantic mode error in the CMake config
+  (https://github.com/fmtlib/fmt/pull/4327). Thanks @rlalik.
+
 # 11.1.2 - 2025-01-12
 
 - Fixed ABI compatibility with earlier 11.x versions

doc/api.md

@@ -669,5 +669,13 @@ following differences:
 
 - Names are defined in the `fmt` namespace instead of `std` to avoid
   collisions with standard library implementations.
+
 - Width calculation doesn't use grapheme clusterization. The latter has
   been implemented in a separate branch but hasn't been integrated yet.
+
+- The default floating-point representation in {fmt} uses the smallest
+  precision that provides round-trip guarantees similarly to other languages
+  like Java and Python. `std::format` is currently specified in terms of
+  `std::to_chars` which tries to generate the smallest number of characters
+  (ignoring redundant digits and sign in exponent) and may procude more
+  decimal digits than necessary.

include/fmt/base.h

@@ -21,7 +21,7 @@
 #endif
 
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
-#define FMT_VERSION 110102
+#define FMT_VERSION 110104
 
 // Detect compiler versions.
 #if defined(__clang__) && !defined(__ibmxl__)
@@ -96,9 +96,9 @@
 // Detect C++14 relaxed constexpr.
 #ifdef FMT_USE_CONSTEXPR
 // Use the provided definition.
-#elif FMT_GCC_VERSION >= 600 && FMT_CPLUSPLUS >= 201402L
-// GCC only allows throw in constexpr since version 6:
-// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67371.
+#elif FMT_GCC_VERSION >= 702 && FMT_CPLUSPLUS >= 201402L
+// GCC only allows constexpr member functions in non-literal types since 7.2:
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66297.
 #  define FMT_USE_CONSTEXPR 1
 #elif FMT_ICC_VERSION
 #  define FMT_USE_CONSTEXPR 0  // https://github.com/fmtlib/fmt/issues/1628
@@ -294,12 +294,12 @@
 #endif
 
 #define FMT_APPLY_VARIADIC(expr) \
-  using ignore = int[];          \
-  (void)ignore { 0, (expr, 0)... }
+  using unused = int[];          \
+  (void)unused { 0, (expr, 0)... }
 
 // Enable minimal optimizations for more compact code in debug mode.
 FMT_PRAGMA_GCC(push_options)
-#if !defined(__OPTIMIZE__) && !defined(__CUDACC__)
+#if !defined(__OPTIMIZE__) && !defined(__CUDACC__) && !defined(FMT_MODULE)
 FMT_PRAGMA_GCC(optimize("Og"))
 #endif
 FMT_PRAGMA_CLANG(diagnostic push)
@@ -537,7 +537,7 @@ template <typename Char> class basic_string_view {
   FMT_ALWAYS_INLINE
 #endif
   FMT_CONSTEXPR20 basic_string_view(const Char* s) : data_(s) {
-#if FMT_HAS_BUILTIN(__buitin_strlen) || FMT_GCC_VERSION || FMT_CLANG_VERSION
+#if FMT_HAS_BUILTIN(__builtin_strlen) || FMT_GCC_VERSION || FMT_CLANG_VERSION
     if (std::is_same<Char, char>::value) {
       size_ = __builtin_strlen(detail::narrow(s));
       return;
@@ -739,13 +739,15 @@ class basic_specs {
     max_fill_size = 4
   };
 
-  size_t data_ = 1 << fill_size_shift;
+  unsigned data_ = 1 << fill_size_shift;
+  static_assert(sizeof(basic_specs::data_) * CHAR_BIT >= 18, "");
 
   // Character (code unit) type is erased to prevent template bloat.
   char fill_data_[max_fill_size] = {' '};
 
   FMT_CONSTEXPR void set_fill_size(size_t size) {
-    data_ = (data_ & ~fill_size_mask) | (size << fill_size_shift);
+    data_ = (data_ & ~fill_size_mask) |
+            (static_cast<unsigned>(size) << fill_size_shift);
   }
 
  public:
@@ -1119,7 +1121,7 @@ using use_formatter =
     bool_constant<(std::is_class<T>::value || std::is_enum<T>::value ||
                    std::is_union<T>::value || std::is_array<T>::value) &&
                   !has_to_string_view<T>::value && !is_named_arg<T>::value &&
-                  !use_format_as<T>::value && !use_format_as_member<T>::value>;
+                  !use_format_as<T>::value && !use_format_as_member<U>::value>;
 
 template <typename Char, typename T, typename U = remove_const_t<T>>
 auto has_formatter_impl(T* p, buffered_context<Char>* ctx = nullptr)
@@ -2261,15 +2263,15 @@ template <> struct is_output_iterator<appender, char> : std::true_type {};
 template <typename It, typename T>
 struct is_output_iterator<
     It, T,
-    void_t<decltype(*std::declval<decay_t<It>&>()++ = std::declval<T>())>>
-    : std::true_type {};
+    enable_if_t<std::is_assignable<decltype(*std::declval<decay_t<It>&>()++),
+                                   T>::value>> : std::true_type {};
 
 #ifndef FMT_USE_LOCALE
 #  define FMT_USE_LOCALE (FMT_OPTIMIZE_SIZE <= 1)
 #endif
 
 // A type-erased reference to an std::locale to avoid a heavy <locale> include.
-struct locale_ref {
+class locale_ref {
 #if FMT_USE_LOCALE
  private:
   const void* locale_;  // A type-erased pointer to std::locale.
@@ -2281,6 +2283,7 @@ struct locale_ref {
   inline explicit operator bool() const noexcept { return locale_ != nullptr; }
 #endif  // FMT_USE_LOCALE
 
+ public:
   template <typename Locale> auto get() const -> Locale;
 };
 
@@ -2654,6 +2657,7 @@ class context {
   FMT_CONSTEXPR auto arg_id(string_view name) const -> int {
     return args_.get_id(name);
   }
+  auto args() const -> const format_args& { return args_; }
 
   // Returns an iterator to the beginning of the output range.
   FMT_CONSTEXPR auto out() const -> iterator { return out_; }
@@ -2726,9 +2730,9 @@ template <typename... T> struct fstring {
                               std::is_same<typename S::char_type, char>::value)>
   FMT_ALWAYS_INLINE fstring(const S&) : str(S()) {
     FMT_CONSTEXPR auto sv = string_view(S());
-    FMT_CONSTEXPR int ignore =
+    FMT_CONSTEXPR int unused =
         (parse_format_string(sv, checker(sv, arg_pack())), 0);
-    detail::ignore_unused(ignore);
+    detail::ignore_unused(unused);
   }
   fstring(runtime_format_string<> fmt) : str(fmt.str) {}
 

include/fmt/compile.h

@@ -19,11 +19,11 @@ FMT_BEGIN_NAMESPACE
 // A compile-time string which is compiled into fast formatting code.
 FMT_EXPORT class compiled_string {};
 
-namespace detail {
-
 template <typename S>
 struct is_compiled_string : std::is_base_of<compiled_string, S> {};
 
+namespace detail {
+
 /**
  * Converts a string literal `s` into a format string that will be parsed at
  * compile time and converted into efficient formatting code. Requires C++17
@@ -41,16 +41,6 @@ struct is_compiled_string : std::is_base_of<compiled_string, S> {};
 #  define FMT_COMPILE(s) FMT_STRING(s)
 #endif
 
-#if FMT_USE_NONTYPE_TEMPLATE_ARGS
-template <typename Char, size_t N, fmt::detail::fixed_string<Char, N> Str>
-struct udl_compiled_string : compiled_string {
-  using char_type = Char;
-  constexpr explicit operator basic_string_view<char_type>() const {
-    return {Str.data, N - 1};
-  }
-};
-#endif
-
 template <typename T, typename... Tail>
 auto first(const T& value, const Tail&...) -> const T& {
   return value;
@@ -425,7 +415,7 @@ constexpr auto compile_format_string(S fmt) {
 }
 
 template <typename... Args, typename S,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 constexpr auto compile(S fmt) {
   constexpr auto str = basic_string_view<typename S::char_type>(fmt);
   if constexpr (str.size() == 0) {
@@ -461,7 +451,7 @@ constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
                                                            Args&&... args) {
   if constexpr (std::is_same<typename S::char_type, char>::value) {
@@ -488,7 +478,7 @@ FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
 }
 
 template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
   constexpr auto compiled = detail::compile<Args...>(S());
   if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
@@ -503,7 +493,7 @@ FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
 #endif
 
 template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 auto format_to_n(OutputIt out, size_t n, const S& fmt, Args&&... args)
     -> format_to_n_result<OutputIt> {
   using traits = detail::fixed_buffer_traits;
@@ -513,7 +503,7 @@ auto format_to_n(OutputIt out, size_t n, const S& fmt, Args&&... args)
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 FMT_CONSTEXPR20 auto formatted_size(const S& fmt, const Args&... args)
     -> size_t {
   auto buf = detail::counting_buffer<>();
@@ -522,7 +512,7 @@ FMT_CONSTEXPR20 auto formatted_size(const S& fmt, const Args&... args)
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 void print(std::FILE* f, const S& fmt, const Args&... args) {
   auto buf = memory_buffer();
   fmt::format_to(appender(buf), fmt, args...);
@@ -530,7 +520,7 @@ void print(std::FILE* f, const S& fmt, const Args&... args) {
 }
 
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(is_compiled_string<S>::value)>
 void print(const S& fmt, const Args&... args) {
   print(stdout, fmt, args...);
 }
@@ -538,9 +528,7 @@ void print(const S& fmt, const Args&... args) {
 #if FMT_USE_NONTYPE_TEMPLATE_ARGS
 inline namespace literals {
 template <detail::fixed_string Str> constexpr auto operator""_cf() {
-  using char_t = remove_cvref_t<decltype(Str.data[0])>;
-  return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
-                                     Str>();
+  return FMT_COMPILE(Str.data);
 }
 }  // namespace literals
 #endif

include/fmt/format.h

@@ -227,7 +227,9 @@ FMT_CONSTEXPR inline void abort_fuzzing_if(bool condition) {
 #if defined(FMT_USE_STRING_VIEW)
 template <typename Char> using std_string_view = std::basic_string_view<Char>;
 #else
-template <typename T> struct std_string_view {};
+template <typename Char> struct std_string_view {
+  operator basic_string_view<Char>() const;
+};
 #endif
 
 template <typename Char, Char... C> struct string_literal {
@@ -1203,7 +1205,7 @@ FMT_CONSTEXPR FMT_INLINE auto format_decimal(Char* out, UInt value,
 }
 
 template <typename Char, typename UInt, typename OutputIt,
-          FMT_ENABLE_IF(is_back_insert_iterator<OutputIt>::value)>
+          FMT_ENABLE_IF(!std::is_pointer<remove_cvref_t<OutputIt>>::value)>
 FMT_CONSTEXPR auto format_decimal(OutputIt out, UInt value, int num_digits)
     -> OutputIt {
   if (auto ptr = to_pointer<Char>(out, to_unsigned(num_digits))) {
@@ -2330,7 +2332,7 @@ template <typename Char, typename OutputIt, typename DecimalFP,
           typename Grouping = digit_grouping<Char>>
 FMT_CONSTEXPR20 auto do_write_float(OutputIt out, const DecimalFP& f,
                                     const format_specs& specs, sign s,
-                                    locale_ref loc) -> OutputIt {
+                                    int exp_upper, locale_ref loc) -> OutputIt {
   auto significand = f.significand;
   int significand_size = get_significand_size(f);
   const Char zero = static_cast<Char>('0');
@@ -2346,7 +2348,7 @@ FMT_CONSTEXPR20 auto do_write_float(OutputIt out, const DecimalFP& f,
     if (specs.type() == presentation_type::fixed) return false;
     // Use the fixed notation if the exponent is in [exp_lower, exp_upper),
     // e.g. 0.0001 instead of 1e-04. Otherwise use the exponent notation.
-    const int exp_lower = -4, exp_upper = 16;
+    const int exp_lower = -4;
     return output_exp < exp_lower ||
            output_exp >= (specs.precision > 0 ? specs.precision : exp_upper);
   };
@@ -2449,12 +2451,13 @@ template <typename Char> class fallback_digit_grouping {
 template <typename Char, typename OutputIt, typename DecimalFP>
 FMT_CONSTEXPR20 auto write_float(OutputIt out, const DecimalFP& f,
                                  const format_specs& specs, sign s,
-                                 locale_ref loc) -> OutputIt {
+                                 int exp_upper, locale_ref loc) -> OutputIt {
   if (is_constant_evaluated()) {
     return do_write_float<Char, OutputIt, DecimalFP,
-                          fallback_digit_grouping<Char>>(out, f, specs, s, loc);
+                          fallback_digit_grouping<Char>>(out, f, specs, s,
+                                                         exp_upper, loc);
   } else {
-    return do_write_float<Char>(out, f, specs, s, loc);
+    return do_write_float<Char>(out, f, specs, s, exp_upper, loc);
   }
 }
 
@@ -3286,6 +3289,14 @@ FMT_CONSTEXPR20 auto format_float(Float value, int precision,
   return exp;
 }
 
+// Numbers with exponents greater or equal to the returned value will use
+// the exponential notation.
+template <typename T> constexpr auto exp_upper() -> int {
+  return std::numeric_limits<T>::digits10 != 0
+             ? min_of(16, std::numeric_limits<T>::digits10 + 1)
+             : 16;
+}
+
 template <typename Char, typename OutputIt, typename T>
 FMT_CONSTEXPR20 auto write_float(OutputIt out, T value, format_specs specs,
                                  locale_ref loc) -> OutputIt {
@@ -3301,6 +3312,7 @@ FMT_CONSTEXPR20 auto write_float(OutputIt out, T value, format_specs specs,
     if (specs.width != 0) --specs.width;
   }
 
+  constexpr int exp_upper = detail::exp_upper<T>();
   int precision = specs.precision;
   if (precision < 0) {
     if (specs.type() != presentation_type::none) {
@@ -3309,7 +3321,7 @@ FMT_CONSTEXPR20 auto write_float(OutputIt out, T value, format_specs specs,
       // Use Dragonbox for the shortest format.
       using floaty = conditional_t<sizeof(T) >= sizeof(double), double, float>;
       auto dec = dragonbox::to_decimal(static_cast<floaty>(value));
-      return write_float<Char>(out, dec, specs, s, loc);
+      return write_float<Char>(out, dec, specs, s, exp_upper, loc);
     }
   }
 
@@ -3337,7 +3349,7 @@ FMT_CONSTEXPR20 auto write_float(OutputIt out, T value, format_specs specs,
 
   specs.precision = precision;
   auto f = big_decimal_fp{buffer.data(), static_cast<int>(buffer.size()), exp};
-  return write_float<Char>(out, f, specs, s, loc);
+  return write_float<Char>(out, f, specs, s, exp_upper, loc);
 }
 
 template <typename Char, typename OutputIt, typename T,
@@ -3364,7 +3376,7 @@ FMT_CONSTEXPR20 auto write(OutputIt out, T value) -> OutputIt {
     return write_nonfinite<Char>(out, std::isnan(value), specs, s);
 
   auto dec = dragonbox::to_decimal(static_cast<floaty>(value));
-  return write_float<Char>(out, dec, specs, s, {});
+  return write_float<Char>(out, dec, specs, s, exp_upper<T>(), {});
 }
 
 template <typename Char, typename OutputIt, typename T,

include/fmt/ostream.h

@@ -150,7 +150,7 @@ inline void vprint(std::ostream& os, string_view fmt, format_args args) {
 FMT_EXPORT template <typename... T>
 void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
   fmt::vargs<T...> vargs = {{args...}};
-  if (detail::use_utf8) return vprint(os, fmt.str, vargs);
+  if (detail::const_check(detail::use_utf8)) return vprint(os, fmt.str, vargs);
   auto buffer = memory_buffer();
   detail::vformat_to(buffer, fmt.str, vargs);
   detail::write_buffer(os, buffer);

include/fmt/ranges.h

@@ -527,7 +527,9 @@ struct formatter<
 template <typename R, typename Char>
 struct formatter<
     R, Char,
-    enable_if_t<range_format_kind<R, Char>::value == range_format::map>> {
+    enable_if_t<conjunction<
+        bool_constant<range_format_kind<R, Char>::value == range_format::map>,
+        detail::is_formattable_delayed<R, Char>>::value>> {
  private:
   using map_type = detail::maybe_const_range<R>;
   using element_type = detail::uncvref_type<map_type>;

src/fmt.cc

@@ -1,5 +1,7 @@
 module;
 
+#define FMT_MODULE
+
 #ifdef _MSVC_LANG
 #  define FMT_CPLUSPLUS _MSVC_LANG
 #else

test/base-test.cc

@@ -875,3 +875,12 @@ TEST(base_test, no_repeated_format_string_conversions) {
   fmt::format_to(buf, nondeterministic_format_string());
 #endif
 }
+
+TEST(base_test, format_context_accessors) {
+  class copier {
+    static fmt::format_context copy(fmt::appender app,
+                                    const fmt::format_context& ctx) {
+      return fmt::format_context(std::move(app), ctx.args(), ctx.locale());
+    }
+  };
+}

test/compile-test.cc

@@ -7,6 +7,8 @@
 
 #include "fmt/compile.h"
 
+#include <iterator>
+#include <list>
 #include <type_traits>
 #include <vector>
 
@@ -199,6 +201,21 @@ TEST(compile_test, format_to_n) {
   EXPECT_STREQ("2a", buffer);
 }
 
+TEST(compile_test, output_iterators) {
+  std::list<char> out;
+  fmt::format_to(std::back_inserter(out), FMT_COMPILE("{}"), 42);
+  EXPECT_EQ("42", std::string(out.begin(), out.end()));
+
+  std::stringstream s;
+  fmt::format_to(std::ostream_iterator<char>(s), FMT_COMPILE("{}"), 42);
+  EXPECT_EQ("42", s.str());
+
+  std::stringstream s2;
+  fmt::format_to(std::ostreambuf_iterator<char>(s2), FMT_COMPILE("{}.{:06d}"),
+                 42, 43);
+  EXPECT_EQ("42.000043", s2.str());
+}
+
 #  if FMT_USE_CONSTEVAL && (!FMT_MSC_VERSION || FMT_MSC_VERSION >= 1940)
 TEST(compile_test, constexpr_formatted_size) {
   FMT_CONSTEXPR20 size_t size = fmt::formatted_size(FMT_COMPILE("{}"), 42);
@@ -299,6 +316,17 @@ TEST(compile_test, compile_format_string_literal) {
 }
 #endif
 
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+template <typename S> auto check_is_compiled_string(const S&) -> bool {
+  return fmt::is_compiled_string<S>::value;
+}
+
+TEST(compile_test, is_compiled_string) {
+  EXPECT_TRUE(check_is_compiled_string(FMT_COMPILE("asdf")));
+  EXPECT_TRUE(check_is_compiled_string(FMT_COMPILE("{}")));
+}
+#endif
+
 // MSVS 2019 19.29.30145.0 - OK
 // MSVS 2022 19.32.31332.0, 19.37.32826.1 - compile-test.cc(362,3): fatal error
 // C1001: Internal compiler error.
@@ -310,7 +338,7 @@ TEST(compile_test, compile_format_string_literal) {
      (FMT_MSC_VERSION >= 1928 && FMT_MSC_VERSION < 1930)) && \
     defined(__cpp_lib_is_constant_evaluated)
 template <size_t max_string_length, typename Char = char> struct test_string {
-  template <typename T> constexpr bool operator==(const T& rhs) const noexcept {
+  template <typename T> constexpr auto operator==(const T& rhs) const -> bool {
     return fmt::basic_string_view<Char>(rhs).compare(buffer) == 0;
   }
   Char buffer[max_string_length]{};

test/format-impl-test.cc

@@ -312,6 +312,7 @@ template <> struct numeric_limits<double_double> {
   // is_iec559 is true for double-double in libstdc++.
   static constexpr bool is_iec559 = true;
   static constexpr int digits = 106;
+  static constexpr int digits10 = 33;
 };
 
 template <> struct is_floating_point<slow_float> : std::true_type {};
@@ -341,7 +342,7 @@ TEST(format_impl_test, write_dragon_even) {
   auto s = std::string();
   fmt::detail::write<char>(std::back_inserter(s), slow_float(33554450.0f), {});
   // Specializing is_floating_point is broken in MSVC.
-  if (!FMT_MSC_VERSION) EXPECT_EQ(s, "33554450");
+  if (!FMT_MSC_VERSION) EXPECT_EQ(s, "3.355445e+07");
 }
 
 #if defined(_WIN32) && !defined(FMT_USE_WRITE_CONSOLE)

test/format-test.cc

@@ -1068,7 +1068,8 @@ TEST(format_test, precision) {
   EXPECT_EQ(fmt::format("{:#.0f}", 123.0), "123.");
   EXPECT_EQ(fmt::format("{:.02f}", 1.234), "1.23");
   EXPECT_EQ(fmt::format("{:.1g}", 0.001), "0.001");
-  EXPECT_EQ(fmt::format("{}", 1019666432.0f), "1019666400");
+  EXPECT_EQ(fmt::format("{}", 123456789.0f), "1.2345679e+08");
+  EXPECT_EQ(fmt::format("{}", 1019666432.0f), "1.0196664e+09");
   EXPECT_EQ(fmt::format("{:.0e}", 9.5), "1e+01");
   EXPECT_EQ(fmt::format("{:.1e}", 1e-34), "1.0e-34");
 
@@ -2102,6 +2103,10 @@ TEST(format_test, output_iterators) {
   std::stringstream s;
   fmt::format_to(std::ostream_iterator<char>(s), "{}", 42);
   EXPECT_EQ("42", s.str());
+
+  std::stringstream s2;
+  fmt::format_to(std::ostreambuf_iterator<char>(s2), "{}.{:06d}", 42, 43);
+  EXPECT_EQ("42.000043", s2.str());
 }
 
 TEST(format_test, fill_via_appender) {

test/ranges-test.cc

@@ -47,6 +47,8 @@ TEST(ranges_test, format_array_of_literals) {
 }
 #endif  // FMT_RANGES_TEST_ENABLE_C_STYLE_ARRAY
 
+struct unformattable {};
+
 TEST(ranges_test, format_vector) {
   auto v = std::vector<int>{1, 2, 3, 5, 7, 11};
   EXPECT_EQ(fmt::format("{}", v), "[1, 2, 3, 5, 7, 11]");
@@ -65,6 +67,9 @@ TEST(ranges_test, format_vector) {
   EXPECT_EQ(fmt::format("{:n}", vvc), "['a', 'b', 'c'], ['a', 'b', 'c']");
   EXPECT_EQ(fmt::format("{:n:n}", vvc), "'a', 'b', 'c', 'a', 'b', 'c'");
   EXPECT_EQ(fmt::format("{:n:n:}", vvc), "a, b, c, a, b, c");
+
+  EXPECT_FALSE(fmt::is_formattable<unformattable>::value);
+  EXPECT_FALSE(fmt::is_formattable<std::vector<unformattable>>::value);
 }
 
 TEST(ranges_test, format_nested_vector) {
@@ -83,6 +88,8 @@ TEST(ranges_test, format_map) {
   auto m = std::map<std::string, int>{{"one", 1}, {"two", 2}};
   EXPECT_EQ(fmt::format("{}", m), "{\"one\": 1, \"two\": 2}");
   EXPECT_EQ(fmt::format("{:n}", m), "\"one\": 1, \"two\": 2");
+
+  EXPECT_FALSE((fmt::is_formattable<std::map<int, unformattable>>::value));
 }
 
 struct test_map_value {};
@@ -146,6 +153,7 @@ template <typename T> class flat_set {
 TEST(ranges_test, format_flat_set) {
   EXPECT_EQ(fmt::format("{}", flat_set<std::string>{"one", "two"}),
             "{\"one\", \"two\"}");
+  EXPECT_FALSE(fmt::is_formattable<flat_set<unformattable>>::value);
 }
 
 namespace adl {
@@ -169,8 +177,6 @@ TEST(ranges_test, format_pair) {
   EXPECT_EQ(fmt::format("{:n}", p), "421.5");
 }
 
-struct unformattable {};
-
 TEST(ranges_test, format_tuple) {
   auto t =
       std::tuple<int, float, std::string, char>(42, 1.5f, "this is tuple", 'i');
@@ -180,7 +186,6 @@ TEST(ranges_test, format_tuple) {
   EXPECT_EQ(fmt::format("{}", std::tuple<>()), "()");
 
   EXPECT_TRUE((fmt::is_formattable<std::tuple<>>::value));
-  EXPECT_FALSE((fmt::is_formattable<unformattable>::value));
   EXPECT_FALSE((fmt::is_formattable<std::tuple<unformattable>>::value));
   EXPECT_FALSE((fmt::is_formattable<std::tuple<unformattable, int>>::value));
   EXPECT_FALSE((fmt::is_formattable<std::tuple<int, unformattable>>::value));
@@ -655,6 +660,8 @@ TEST(ranges_test, container_adaptor) {
     m.push(2);
     EXPECT_EQ(fmt::format("{}", m), "[1, 2]");
   }
+
+  EXPECT_FALSE(fmt::is_formattable<std::stack<unformattable>>::value);
 }
 
 struct tieable {

test/std-test.cc

@@ -13,13 +13,17 @@
 #include <vector>
 
 #include "fmt/os.h"  // fmt::system_category
-#include "fmt/ranges.h"
 #include "gtest-extra.h"  // StartsWith
 
 #ifdef __cpp_lib_filesystem
 TEST(std_test, path) {
   using std::filesystem::path;
   EXPECT_EQ(fmt::format("{}", path("/usr/bin")), "/usr/bin");
+
+  // see #4303
+  const path p = "/usr/bin";
+  EXPECT_EQ(fmt::format("{}", p), "/usr/bin");
+
   EXPECT_EQ(fmt::format("{:?}", path("/usr/bin")), "\"/usr/bin\"");
   EXPECT_EQ(fmt::format("{:8}", path("foo")), "foo     ");
 
@@ -44,6 +48,9 @@ TEST(std_test, path) {
 #  endif
 }
 
+// Intentionally delayed include to test #4303
+#include "fmt/ranges.h"
+
 // Test ambiguity problem described in #2954.
 TEST(ranges_std_test, format_vector_path) {
   auto p = std::filesystem::path("foo/bar.txt");