Revert "[libc++][TZDB] Implements time_zone::to_sys. (llvm#90394)"

This reverts commit 77116bd.

Author: fmayer

libcxx/include/CMakeLists.txt

@@ -250,7 +250,6 @@ set(files
   __chrono/convert_to_tm.h
   __chrono/day.h
   __chrono/duration.h
-  __chrono/exception.h
   __chrono/file_clock.h
   __chrono/formatter.h
   __chrono/hh_mm_ss.h

libcxx/include/__chrono/exception.h

@@ -18,14 +18,12 @@
 
 #  include <__chrono/calendar.h>
 #  include <__chrono/duration.h>
-#  include <__chrono/exception.h>
 #  include <__chrono/local_info.h>
 #  include <__chrono/sys_info.h>
 #  include <__chrono/system_clock.h>
 #  include <__compare/strong_order.h>
 #  include <__config>
 #  include <__memory/unique_ptr.h>
-#  include <__type_traits/common_type.h>
 #  include <string_view>
 
 #  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -72,31 +70,6 @@ class _LIBCPP_AVAILABILITY_TZDB time_zone {
     return __get_info(chrono::time_point_cast<seconds>(__time));
   }
 
-  // We don't apply nodiscard here since this function throws on many inputs,
-  // so it could be used as a validation.
-  template <class _Duration>
-  _LIBCPP_HIDE_FROM_ABI sys_time<common_type_t<_Duration, seconds>> to_sys(const local_time<_Duration>& __time) const {
-    local_info __info = get_info(__time);
-    switch (__info.result) {
-    case local_info::unique:
-      return sys_time<common_type_t<_Duration, seconds>>{__time.time_since_epoch() - __info.first.offset};
-
-    case local_info::nonexistent:
-      chrono::__throw_nonexistent_local_time(__time, __info);
-
-    case local_info::ambiguous:
-      chrono::__throw_ambiguous_local_time(__time, __info);
-    }
-
-    // TODO TZDB The Standard does not specify anything in these cases.
-    _LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(
-        __info.result != -1, "cannot convert the local time; it would be before the minimum system clock value");
-    _LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(
-        __info.result != -2, "cannot convert the local time; it would be after the maximum system clock value");
-
-    return {};
-  }
-
   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI const __impl& __implementation() const noexcept { return *__impl_; }
 
 private:

libcxx/include/__chrono/time_zone.h

@@ -724,10 +724,6 @@ const time_zone* current_zone()
 const tzdb& reload_tzdb();                                                       // C++20
 string remote_version();                                                         // C++20
 
-// [time.zone.exception], exception classes
-class nonexistent_local_time;                                                    // C++20
-class ambiguous_local_time;                                                      // C++20
-
 // [time.zone.info], information classes
 struct sys_info {                                                                // C++20
   sys_seconds   begin;
@@ -770,10 +766,6 @@ class time_zone {
 
   template<class Duration>
   local_info get_info(const local_time<Duration>& tp) const;
-
-  template<class Duration>
-  sys_time<common_type_t<Duration, seconds>>
-    to_sys(const local_time<Duration>& tp) const;
 };
 bool operator==(const time_zone& x, const time_zone& y) noexcept;                // C++20
 strong_ordering operator<=>(const time_zone& x, const time_zone& y) noexcept;    // C++20
@@ -923,7 +915,6 @@ constexpr chrono::year                                  operator ""y(unsigned lo
 #if _LIBCPP_STD_VER >= 20
 #  include <__chrono/calendar.h>
 #  include <__chrono/day.h>
-#  include <__chrono/exception.h>
 #  include <__chrono/hh_mm_ss.h>
 #  include <__chrono/literals.h>
 #  include <__chrono/local_info.h>

libcxx/include/chrono

@@ -1101,7 +1101,6 @@ module std_private_chrono_duration               [system] {
   header "__chrono/duration.h"
   export std_private_type_traits_is_convertible
 }
-module std_private_chrono_exception              [system] { header "__chrono/exception.h" }
 module std_private_chrono_file_clock             [system] { header "__chrono/file_clock.h" }
 module std_private_chrono_formatter              [system] {
   header "__chrono/formatter.h"
@@ -1114,10 +1113,7 @@ module std_private_chrono_high_resolution_clock  [system] {
 }
 module std_private_chrono_leap_second            [system] { header "__chrono/leap_second.h" }
 module std_private_chrono_literals               [system] { header "__chrono/literals.h" }
-module std_private_chrono_local_info             [system] {
-  header "__chrono/local_info.h"
-  export std_private_chrono_sys_info
-}
+module std_private_chrono_local_info             [system] { header "__chrono/local_info.h" }
 module std_private_chrono_month                  [system] { header "__chrono/month.h" }
 module std_private_chrono_month_weekday          [system] { header "__chrono/month_weekday.h" }
 module std_private_chrono_monthday               [system] { header "__chrono/monthday.h" }

libcxx/include/module.modulemap

@@ -209,12 +209,13 @@ export namespace std {
     using std::chrono::reload_tzdb;
     using std::chrono::remote_version;
 
-#  endif //  !defined(_LIBCPP_HAS_NO_TIME_ZONE_DATABASE) && !defined(_LIBCPP_HAS_NO_FILESYSTEM) &&
-         //  !defined(_LIBCPP_HAS_NO_LOCALIZATION)
-
+#    if 0
     // [time.zone.exception], exception classes
     using std::chrono::ambiguous_local_time;
     using std::chrono::nonexistent_local_time;
+#    endif // if 0
+#  endif   //  !defined(_LIBCPP_HAS_NO_TIME_ZONE_DATABASE) && !defined(_LIBCPP_HAS_NO_FILESYSTEM) &&
+           //  !defined(_LIBCPP_HAS_NO_LOCALIZATION)
 
     // [time.zone.info], information classes
     using std::chrono::local_info;

libcxx/modules/std/chrono.inc

@@ -340,9 +340,6 @@ if (LIBCXX_ENABLE_LOCALIZATION AND LIBCXX_ENABLE_FILESYSTEM AND LIBCXX_ENABLE_TI
     include/tzdb/types_private.h
     include/tzdb/tzdb_list_private.h
     include/tzdb/tzdb_private.h
-    # TODO TZDB The exception could be moved in chrono once the TZDB library
-    # is no longer experimental.
-    chrono_exception.cpp
     time_zone.cpp
     tzdb.cpp
     tzdb_list.cpp