Revert "[libc++][format] P3953R3: Rename std::runtime_format (#189657)" (#191912)

This reverts commit 67c893eebc due to
buildbot breakage

(https://github.com/llvm/llvm-project/pull/189657#issuecomment-4231358706,
https://github.com/llvm/llvm-project/pull/189657#issuecomment-4239964862).

libcxx/docs/ReleaseNotes/23.rst

@@ -40,7 +40,6 @@ Implemented Papers
 
 - P2440R1: ``ranges::iota``, ``ranges::shift_left`` and ``ranges::shift_right`` (`Github <https://llvm.org/PR105184>`__)
 - P3936R1: Safer ``atomic_ref::address`` (`Github <https://llvm.org/PR189594>`__)
-- P3953R3: Rename ``std::runtime_format`` (`Github <https://llvm.org/PR189624>`__)
 - P4052R0: Renaming saturation arithmetic functions (`Github <https://llvm.org/PR189589>`__)
 
 Improvements and New Features

libcxx/docs/Status/Cxx2cPapers.csv

@@ -207,7 +207,7 @@
 "`P3826R5 <https://wg21.link/P3826R5>`__","Fix Sender Algorithm Customization","2026-03 (Croydon)","","","`#189620 <https://github.com/llvm/llvm-project/issues/189620>`__",""
 "`P3980R1 <https://wg21.link/P3980R1>`__","Task's Allocator Use","2026-03 (Croydon)","","","`#189621 <https://github.com/llvm/llvm-project/issues/189621>`__",""
 "`P4156R0 <https://wg21.link/P4156R0>`__","Rename meta::has_ellipsis_parameter to meta::is_vararg_function","2026-03 (Croydon)","","","`#189622 <https://github.com/llvm/llvm-project/issues/189622>`__",""
-"`P3953R3 <https://wg21.link/P3953R3>`__","Rename ``std::runtime_format``","2026-03 (Croydon)","|Complete|","23","`#189624 <https://github.com/llvm/llvm-project/issues/189624>`__",""
+"`P3953R3 <https://wg21.link/P3953R3>`__","Rename ``std::runtime_format``","2026-03 (Croydon)","","","`#189624 <https://github.com/llvm/llvm-project/issues/189624>`__",""
 "`P4052R0 <https://wg21.link/P4052R0>`__","Renaming saturation arithmetic functions","2026-03 (Croydon)","|Complete|","23","`#189589 <https://github.com/llvm/llvm-project/issues/189589>`__",""
 "`P3941R4 <https://wg21.link/P3941R4>`__","Scheduler Affinity","2026-03 (Croydon)","","","`#189627 <https://github.com/llvm/llvm-project/issues/189627>`__",""
 "`P3856R8 <https://wg21.link/P3856R8>`__","New reflection metafunction - is_structural_type (US NB comment 49)","2026-03 (Croydon)","","","`#189625 <https://github.com/llvm/llvm-project/issues/189625>`__",""

libcxx/include/__format/format_functions.h

@@ -342,7 +342,7 @@ _LIBCPP_HIDE_FROM_ABI constexpr typename _Ctx::iterator __vformat_to(_ParseCtx&&
 
 #  if _LIBCPP_STD_VER >= 26
 template <class _CharT>
-struct __dynamic_format_string {
+struct __runtime_format_string {
 private:
   basic_string_view<_CharT> __str_;
 
@@ -350,15 +350,15 @@ private:
   friend struct basic_format_string;
 
 public:
-  _LIBCPP_HIDE_FROM_ABI __dynamic_format_string(basic_string_view<_CharT> __s) noexcept : __str_(__s) {}
+  _LIBCPP_HIDE_FROM_ABI __runtime_format_string(basic_string_view<_CharT> __s) noexcept : __str_(__s) {}
 
-  __dynamic_format_string(const __dynamic_format_string&)            = delete;
-  __dynamic_format_string& operator=(const __dynamic_format_string&) = delete;
+  __runtime_format_string(const __runtime_format_string&)            = delete;
+  __runtime_format_string& operator=(const __runtime_format_string&) = delete;
 };
 
-_LIBCPP_HIDE_FROM_ABI inline __dynamic_format_string<char> dynamic_format(string_view __fmt) noexcept { return __fmt; }
+_LIBCPP_HIDE_FROM_ABI inline __runtime_format_string<char> runtime_format(string_view __fmt) noexcept { return __fmt; }
 #    if _LIBCPP_HAS_WIDE_CHARACTERS
-_LIBCPP_HIDE_FROM_ABI inline __dynamic_format_string<wchar_t> dynamic_format(wstring_view __fmt) noexcept {
+_LIBCPP_HIDE_FROM_ABI inline __runtime_format_string<wchar_t> runtime_format(wstring_view __fmt) noexcept {
   return __fmt;
 }
 #    endif
@@ -375,7 +375,7 @@ struct basic_format_string {
 
   _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<_CharT> get() const noexcept { return __str_; }
 #  if _LIBCPP_STD_VER >= 26
-  _LIBCPP_HIDE_FROM_ABI basic_format_string(__dynamic_format_string<_CharT> __s) noexcept : __str_(__s.__str_) {}
+  _LIBCPP_HIDE_FROM_ABI basic_format_string(__runtime_format_string<_CharT> __s) noexcept : __str_(__s.__str_) {}
 #  endif
 
 private:

libcxx/include/format

@@ -31,7 +31,7 @@ namespace std {
 
     public:
       template<class T> consteval basic_format_string(const T& s);
-      basic_format_string(dynamic-format-string<charT> s) noexcept : str(s.str) {}   // since C++26
+      basic_format_string(runtime-format-string<charT> s) noexcept : str(s.str) {}   // since C++26
 
       constexpr basic_string_view<charT> get() const noexcept { return str; }
     };
@@ -42,21 +42,21 @@ namespace std {
     using wformat_string =                                      // since C++23, exposition only before C++23
       basic_format_string<wchar_t, type_identity_t<Args>...>;
 
-  template<class charT> struct dynamic-format-string {          // since C++26, exposition-only
+  template<class charT> struct runtime-format-string {          // since C++26, exposition-only
   private:
     basic_string_view<charT> str;                               // exposition-only
 
   public:
-    dynamic-format-string(basic_string_view<charT> s) noexcept : str(s) {}
+    runtime-format-string(basic_string_view<charT> s) noexcept : str(s) {}
 
-    dynamic-format-string(const dynamic-format-string&) = delete;
-    dynamic-format-string& operator=(const dynamic-format-string&) = delete;
+    runtime-format-string(const runtime-format-string&) = delete;
+    runtime-format-string& operator=(const runtime-format-string&) = delete;
   };
 
-  dynamic-format-string<char> dynamic_format(string_view fmt) noexcept {
+  runtime-format-string<char> runtime_format(string_view fmt) noexcept {
     return fmt;
   }
-  dynamic-format-string<wchar_t> dynamic_format(wstring_view fmt) noexcept {
+  runtime-format-string<wchar_t> runtime_format(wstring_view fmt) noexcept {
     return fmt;
   }
 

libcxx/modules/std/format.inc

@@ -29,7 +29,7 @@ export namespace std {
   using std::wformat_string;
 #endif
 #if _LIBCPP_STD_VER >= 26
-  using std::dynamic_format;
+  using std::runtime_format;
 #endif // _LIBCPP_STD_VER >= 26
 
   // [format.functions], formatting functions

libcxx/test/std/utilities/format/format.fmt.string/ctor.runtime-format-string.pass.cpp

@@ -13,11 +13,11 @@
 // template<class charT, class... Args>
 // class basic_format_string<charT, type_identity_t<Args>...>
 //
-// basic_format_string(dynamic-format-string<charT> s) noexcept : str(s.str) {}
+// basic_format_string(runtime-format-string<charT> s) noexcept : str(s.str) {}
 //
 // Additional testing is done in
-// - libcxx/test/std/utilities/format/format.functions/format.dynamic_format.pass.cpp
-// - libcxx/test/std/utilities/format/format.functions/format.locale.dynamic_format.pass.cpp
+// - libcxx/test/std/utilities/format/format.functions/format.runtime_format.pass.cpp
+// - libcxx/test/std/utilities/format/format.functions/format.locale.runtime_format.pass.cpp
 
 #include <format>
 #include <cassert>
@@ -25,16 +25,16 @@
 #include "test_macros.h"
 
 int main(int, char**) {
-  static_assert(noexcept(std::format_string<>{std::dynamic_format(std::string_view{})}));
+  static_assert(noexcept(std::format_string<>{std::runtime_format(std::string_view{})}));
   {
-    std::format_string<> s = std::dynamic_format("}{invalid format string}{");
+    std::format_string<> s = std::runtime_format("}{invalid format string}{");
     assert(s.get() == "}{invalid format string}{");
   }
 
 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
-  static_assert(noexcept(std::wformat_string<>{std::dynamic_format(std::wstring_view{})}));
+  static_assert(noexcept(std::wformat_string<>{std::runtime_format(std::wstring_view{})}));
   {
-    std::wformat_string<> s = std::dynamic_format(L"}{invalid format string}{");
+    std::wformat_string<> s = std::runtime_format(L"}{invalid format string}{");
     assert(s.get() == L"}{invalid format string}{");
   }
 #endif // TEST_HAS_NO_WIDE_CHARACTERS

libcxx/test/std/utilities/format/format.functions/format.locale.runtime_format.pass.cpp

@@ -16,15 +16,15 @@
 
 // Tests the behavior of
 //
-// dynamic-format-string<char> dynamic_format(string_view fmt) noexcept;
-// dynamic-format-string<wchar_t> dynamic_format(wstring_view fmt) noexcept;
+// runtime-format-string<char> runtime_format(string_view fmt) noexcept;
+// runtime-format-string<wchar_t> runtime_format(wstring_view fmt) noexcept;
 //
 // and
 //
 // template<class charT, class... Args>
 //   struct basic_format_string {
 //   ...
-//   basic_format_string(dynamic-format-string<charT> s) noexcept : str(s.str) {}
+//   basic_format_string(runtime-format-string<charT> s) noexcept : str(s.str) {}
 //   ...
 // }
 //
@@ -35,9 +35,9 @@
 // template<class... Args>
 //   wstring format(const locale& loc, wformat_string<Args...> fmt, Args&&... args);
 //
-// The basics of dynamic_format and basic_format_string's constructor are tested in
-// - libcxx/test/std/utilities/format/format.syn/dynamic_format_string.pass.cpp
-// - libcxx/test/std/utilities/format/format.fmt.string/ctor.dynamic-format-string.pass.cpp
+// The basics of runtime_format and basic_format_string's constructor are tested in
+// - libcxx/test/std/utilities/format/format.syn/runtime_format_string.pass.cpp
+// - libcxx/test/std/utilities/format/format.fmt.string/ctor.runtime-format-string.pass.cpp
 
 #include <format>
 #include <cassert>
@@ -52,7 +52,7 @@
 
 auto test = []<class CharT, class... Args>(
                 std::basic_string_view<CharT> expected, std::basic_string_view<CharT> fmt, Args&&... args) constexpr {
-  std::basic_string<CharT> out = std::format(std::locale(), std::dynamic_format(fmt), std::forward<Args>(args)...);
+  std::basic_string<CharT> out = std::format(std::locale(), std::runtime_format(fmt), std::forward<Args>(args)...);
   TEST_REQUIRE(out == expected,
                TEST_WRITE_CONCATENATED(
                    "\nFormat string   ", fmt, "\nExpected output ", expected, "\nActual output   ", out, '\n'));
@@ -71,7 +71,7 @@ auto test_exception =
                 TEST_WRITE_CONCATENATED(
                     "\nFormat string   ", fmt, "\nExpected exception ", what, "\nActual exception   ", e.what(), '\n'));
           },
-          TEST_IGNORE_NODISCARD std::format(std::locale(), std::dynamic_format(fmt), std::forward<Args>(args)...));
+          TEST_IGNORE_NODISCARD std::format(std::locale(), std::runtime_format(fmt), std::forward<Args>(args)...));
     };
 
 int main(int, char**) {

libcxx/test/std/utilities/format/format.functions/format.runtime_format.pass.cpp

@@ -15,15 +15,15 @@
 
 // Tests the behavior of
 //
-// dynamic-format-string<char> dynamic_format(string_view fmt) noexcept;
-// dynamic-format-string<wchar_t> dynamic_format(wstring_view fmt) noexcept;
+// runtime-format-string<char> runtime_format(string_view fmt) noexcept;
+// runtime-format-string<wchar_t> runtime_format(wstring_view fmt) noexcept;
 //
 // and
 //
 // template<class charT, class... Args>
 //   struct basic_format_string {
 //   ...
-//   basic_format_string(dynamic-format-string<charT> s) noexcept : str(s.str) {}
+//   basic_format_string(runtime-format-string<charT> s) noexcept : str(s.str) {}
 //   ...
 // }
 //
@@ -34,9 +34,9 @@
 // template<class... Args>
 //   wstring format(wformat_string<Args...> fmt, Args&&... args);
 //
-// The basics of dynamic_format and basic_format_string's constructor are tested in
-// - libcxx/test/std/utilities/format/format.syn/dynamic_format_string.pass.cpp
-// - libcxx/test/std/utilities/format/format.fmt.string/ctor.dynamic-format-string.pass.cpp
+// The basics of runtime_format and basic_format_string's constructor are tested in
+// - libcxx/test/std/utilities/format/format.syn/runtime_format_string.pass.cpp
+// - libcxx/test/std/utilities/format/format.fmt.string/ctor.runtime-format-string.pass.cpp
 
 #include <format>
 #include <cassert>
@@ -50,7 +50,7 @@
 
 auto test = []<class CharT, class... Args>(
                 std::basic_string_view<CharT> expected, std::basic_string_view<CharT> fmt, Args&&... args) constexpr {
-  std::basic_string<CharT> out = std::format(std::dynamic_format(fmt), std::forward<Args>(args)...);
+  std::basic_string<CharT> out = std::format(std::runtime_format(fmt), std::forward<Args>(args)...);
   TEST_REQUIRE(out == expected,
                TEST_WRITE_CONCATENATED(
                    "\nFormat string   ", fmt, "\nExpected output ", expected, "\nActual output   ", out, '\n'));
@@ -69,7 +69,7 @@ auto test_exception =
                 TEST_WRITE_CONCATENATED(
                     "\nFormat string   ", fmt, "\nExpected exception ", what, "\nActual exception   ", e.what(), '\n'));
           },
-          TEST_IGNORE_NODISCARD std::format(std::dynamic_format(fmt), std::forward<Args>(args)...));
+          TEST_IGNORE_NODISCARD std::format(std::runtime_format(fmt), std::forward<Args>(args)...));
     };
 
 int main(int, char**) {

libcxx/test/std/utilities/format/format.syn/runtime_format_string.pass.cpp

@@ -10,23 +10,23 @@
 
 // <format>
 
-// template<class charT> struct dynamic-format-string {  // exposition-only
+// template<class charT> struct runtime-format-string {  // exposition-only
 // private:
 //   basic_string_view<charT> str;  // exposition-only
 //
 // public:
-//   dynamic-format-string(basic_string_view<charT> s) noexcept : str(s) {}
+//   runtime-format-string(basic_string_view<charT> s) noexcept : str(s) {}
 //
-//   dynamic-format-string(const dynamic-format-string&) = delete;
-//   dynamic-format-string& operator=(const dynamic-format-string&) = delete;
+//   runtime-format-string(const runtime-format-string&) = delete;
+//   runtime-format-string& operator=(const runtime-format-string&) = delete;
 // };
 //
-// dynamic-format-string<char> dynamic_format(string_view fmt) noexcept;
-// dynamic-format-string<wchar_t> dynamic_format(wstring_view fmt) noexcept;
+// runtime-format-string<char> runtime_format(string_view fmt) noexcept;
+// runtime-format-string<wchar_t> runtime_format(wstring_view fmt) noexcept;
 //
 // Additional testing is done in
-// - libcxx/test/std/utilities/format/format.functions/format.dynamic_format.pass.cpp
-// - libcxx/test/std/utilities/format/format.functions/format.locale.dynamic_format.pass.cpp
+// - libcxx/test/std/utilities/format/format.functions/format.runtime_format.pass.cpp
+// - libcxx/test/std/utilities/format/format.functions/format.locale.runtime_format.pass.cpp
 
 #include <format>
 
@@ -50,19 +50,19 @@ static void test_properties() {
 }
 
 int main(int, char**) {
-  static_assert(noexcept(std::dynamic_format(std::string_view{})));
-  auto format_string = std::dynamic_format(std::string_view{});
+  static_assert(noexcept(std::runtime_format(std::string_view{})));
+  auto format_string = std::runtime_format(std::string_view{});
 
   using FormatString = decltype(format_string);
-  LIBCPP_ASSERT((std::same_as<FormatString, std::__dynamic_format_string<char>>));
+  LIBCPP_ASSERT((std::same_as<FormatString, std::__runtime_format_string<char>>));
   test_properties<FormatString, char>();
 
 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
-  static_assert(noexcept(std::dynamic_format(std::wstring_view{})));
-  auto wformat_string = std::dynamic_format(std::wstring_view{});
+  static_assert(noexcept(std::runtime_format(std::wstring_view{})));
+  auto wformat_string = std::runtime_format(std::wstring_view{});
 
   using WFormatString = decltype(wformat_string);
-  LIBCPP_ASSERT((std::same_as<WFormatString, std::__dynamic_format_string<wchar_t>>));
+  LIBCPP_ASSERT((std::same_as<WFormatString, std::__runtime_format_string<wchar_t>>));
   test_properties<WFormatString, wchar_t>();
 #endif // TEST_HAS_NO_WIDE_CHARACTERS
 

libcxx/utils/generate_feature_test_macro_components.py

@@ -572,7 +572,6 @@ feature_test_macros = [
                 # "c++23": 202207, Not implemented P2419R2 Clarify handling of encodings in localized formatting of chrono types
                 # "c++26": 202306, P2637R3 Member Visit (implemented)
                 # "c++26": 202311, P2918R2 Runtime format strings II (implemented)
-                # "c++26": 202603, P3953R3 Rename std::runtime_format (implemented)
             },
             # Note these three papers are adopted at the June 2023 meeting and have sequential numbering
             # 202304 P2510R3 Formatting pointers (Implemented)