Add support for zzzz (and beyond) in format_datetime (#11330)

Summary:

This diff adds support for JODA's zzzz (or more) patterns (all equivalent) in Presto's
format_datetime function.

This is used to format long time zone names.

Long time zone names are not available from the IANA time zone database, so we
can't use the tz library to generate these.  Fortunately, unicode provides some
utilities to generate these.

Reviewed By: pedroerp

Differential Revision: D64795407

CMake/resolve_dependency_modules/boost.cmake

@@ -13,30 +13,13 @@
 # limitations under the License.
 include_guard(GLOBAL)
 
-if(CMAKE_SYSTEM_NAME MATCHES "Darwin")
-  if(ON_APPLE_M1)
-    list(APPEND CMAKE_PREFIX_PATH "/opt/homebrew/opt/icu4c")
-  else()
-    list(APPEND CMAKE_PREFIX_PATH "/usr/local/opt/icu4c")
-  endif()
-endif()
-
-# ICU is only needed with Boost build from source
-set_source(ICU)
-resolve_dependency(
-  ICU
-  COMPONENTS
-  data
-  i18n
-  io
-  uc
-  tu
-  test)
-
 add_subdirectory(${CMAKE_CURRENT_LIST_DIR}/boost)
-if(${ICU_SOURCE} STREQUAL "BUNDLED")
-  # ensure ICU is built before Boost
-  add_dependencies(boost_regex ICU ICU::i18n)
+
+if(ICU_SOURCE)
+  if(${ICU_SOURCE} STREQUAL "BUNDLED")
+    # ensure ICU is built before Boost
+    add_dependencies(boost_regex ICU ICU::i18n)
+  endif()
 endif()
 
 # This prevents system boost from leaking in

CMakeLists.txt

@@ -385,6 +385,25 @@ endif()
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
+if(CMAKE_SYSTEM_NAME MATCHES "Darwin")
+  if(ON_APPLE_M1)
+    list(APPEND CMAKE_PREFIX_PATH "/opt/homebrew/opt/icu4c")
+  else()
+    list(APPEND CMAKE_PREFIX_PATH "/usr/local/opt/icu4c")
+  endif()
+endif()
+
+set_source(ICU)
+resolve_dependency(
+  ICU
+  COMPONENTS
+  data
+  i18n
+  io
+  uc
+  tu
+  test)
+
 set(BOOST_INCLUDE_LIBRARIES
     atomic
     context

velox/functions/lib/CMakeLists.txt

@@ -24,7 +24,8 @@ velox_link_libraries(velox_functions_util velox_vector velox_common_base)
 velox_add_library(velox_functions_lib_date_time_formatter DateTimeFormatter.cpp
                   DateTimeFormatterBuilder.cpp)
 
-velox_link_libraries(velox_functions_lib_date_time_formatter velox_type_tz)
+velox_link_libraries(velox_functions_lib_date_time_formatter velox_type_tz
+                     ICU::i18n ICU::uc)
 
 velox_add_library(
   velox_functions_lib

velox/functions/lib/DateTimeFormatter.cpp

@@ -1209,10 +1209,10 @@ uint32_t DateTimeFormatter::maxResultSize(const tz::TimeZone* timezone) const {
           // https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
           size += 5;
         } else {
-          VELOX_NYI(
-              "Date format specifier is not yet implemented: {} ({})",
-              getSpecifierName(token.pattern.specifier),
-              token.pattern.minRepresentDigits);
+          // The longest time zone long name is 40, Australian Central Western
+          // Standard Time.
+          // https://www.timeanddate.com/time/zones/
+          size += 50;
         }
 
         break;
@@ -1468,8 +1468,11 @@ int32_t DateTimeFormatter::format(
             std::memcpy(result, abbrev.data(), abbrev.length());
             result += abbrev.length();
           } else {
-            // TODO: implement full name time zone
-            VELOX_NYI("full time zone name is not yet supported");
+            std::string longName = timezone->getLongName(
+                std::chrono::milliseconds(timestamp.toMillis()),
+                tz::TimeZone::TChoose::kEarliest);
+            std::memcpy(result, longName.data(), longName.length());
+            result += longName.length();
           }
         } break;
 

velox/functions/prestosql/tests/DateTimeFunctionsTest.cpp

@@ -3272,6 +3272,12 @@ TEST_F(DateTimeFunctionsTest, formatDateTime) {
   EXPECT_EQ("IST", formatDatetime(parseTimestamp("1970-01-01"), "zzz"));
   EXPECT_EQ("IST", formatDatetime(parseTimestamp("1970-01-01"), "zz"));
   EXPECT_EQ("IST", formatDatetime(parseTimestamp("1970-01-01"), "z"));
+  EXPECT_EQ(
+      "India Standard Time",
+      formatDatetime(parseTimestamp("1970-01-01"), "zzzz"));
+  EXPECT_EQ(
+      "India Standard Time",
+      formatDatetime(parseTimestamp("1970-01-01"), "zzzzzzzzzzzzzzzzzzzzzz"));
 
   // Test daylight savings.
   setQueryTimeZone("America/Los_Angeles");
@@ -3281,16 +3287,47 @@ TEST_F(DateTimeFunctionsTest, formatDateTime) {
   EXPECT_EQ("PDT", formatDatetime(parseTimestamp("2024-03-10 03:00"), "z"));
   EXPECT_EQ("PDT", formatDatetime(parseTimestamp("2024-11-03 01:00"), "z"));
   EXPECT_EQ("PST", formatDatetime(parseTimestamp("2024-11-03 02:00"), "z"));
+  EXPECT_EQ(
+      "Pacific Standard Time",
+      formatDatetime(parseTimestamp("1970-01-01"), "zzzz"));
+  EXPECT_EQ(
+      "Pacific Daylight Time",
+      formatDatetime(parseTimestamp("1970-10-01"), "zzzz"));
+  EXPECT_EQ(
+      "Pacific Standard Time",
+      formatDatetime(parseTimestamp("2024-03-10 01:00"), "zzzz"));
+  EXPECT_EQ(
+      "Pacific Daylight Time",
+      formatDatetime(parseTimestamp("2024-03-10 03:00"), "zzzz"));
+  EXPECT_EQ(
+      "Pacific Daylight Time",
+      formatDatetime(parseTimestamp("2024-11-03 01:00"), "zzzz"));
+  EXPECT_EQ(
+      "Pacific Standard Time",
+      formatDatetime(parseTimestamp("2024-11-03 02:00"), "zzzz"));
+
+  // Test ambiguous time.
+  EXPECT_EQ(
+      "PDT", formatDatetime(parseTimestamp("2024-11-03 01:30:00"), "zzz"));
+  EXPECT_EQ(
+      "Pacific Daylight Time",
+      formatDatetime(parseTimestamp("2024-11-03 01:30:00"), "zzzz"));
 
   // Test a long abbreviation.
   setQueryTimeZone("Asia/Colombo");
   EXPECT_EQ("+0530", formatDatetime(parseTimestamp("1970-10-01"), "z"));
+  EXPECT_EQ(
+      "India Standard Time",
+      formatDatetime(parseTimestamp("1970-10-01"), "zzzz"));
 
-  setQueryTimeZone("Asia/Kolkata");
-  // We don't support more than 3 'z's yet.
-  EXPECT_THROW(
-      formatDatetime(parseTimestamp("1970-01-01"), "zzzz"), VeloxRuntimeError);
+  // Test a long long name.
+  setQueryTimeZone("Australia/Eucla");
+  EXPECT_EQ("+0845", formatDatetime(parseTimestamp("1970-10-01"), "z"));
+  EXPECT_EQ(
+      "Australian Central Western Standard Time",
+      formatDatetime(parseTimestamp("1970-10-01"), "zzzz"));
 
+  setQueryTimeZone("Asia/Kolkata");
   // Literal test cases.
   EXPECT_EQ("hello", formatDatetime(parseTimestamp("1970-01-01"), "'hello'"));
   EXPECT_EQ("'", formatDatetime(parseTimestamp("1970-01-01"), "''"));

velox/type/tz/CMakeLists.txt

@@ -23,4 +23,6 @@ velox_link_libraries(
   velox_external_date
   Boost::regex
   fmt::fmt
-  Folly::folly)
+  Folly::folly
+  ICU::i18n
+  ICU::uc)

velox/type/tz/TimeZoneMap.cpp

@@ -20,6 +20,16 @@
 #include <fmt/core.h>
 #include <folly/container/F14Map.h>
 #include <folly/container/F14Set.h>
+
+#include <unicode/locid.h>
+#include <unicode/timezone.h>
+#include <unicode/unistr.h>
+
+// The ICU libraries define TRUE/FALSE macros which frequently conflict with
+// other libraries that use these as enum/variable names.
+#undef TRUE
+#undef FALSE
+
 #include "velox/common/base/Exceptions.h"
 #include "velox/common/testutil/TestValue.h"
 #include "velox/external/date/tz.h"
@@ -379,4 +389,48 @@ std::string TimeZone::getShortName(
 
   return getZonedTime(tz_, timePoint, choose).get_info().abbrev;
 }
+
+std::string TimeZone::getLongName(
+    TimeZone::milliseconds timestamp,
+    TimeZone::TChoose choose) const {
+  static const icu::Locale locale("en", "US");
+
+  validateRange(date::sys_time<milliseconds>(timestamp));
+
+  // Time zone offsets only have one name.
+  if (tz_ == nullptr) {
+    return timeZoneName_;
+  }
+
+  // Special case for UTC. ICU uses "GMT" for some reason which is an
+  // abbreviation.
+  if (timeZoneID_ == 0) {
+    return "Coordinated Universal Time";
+  }
+
+  // Get the ICU TimeZone by name
+  std::unique_ptr<icu::TimeZone> tz(icu::TimeZone::createTimeZone(
+      icu::UnicodeString(timeZoneName_.data(), timeZoneName_.length())));
+  VELOX_USER_CHECK_NOT_NULL(tz);
+
+  // According to the documentation this is how to determine if DST applies to
+  // a given timestamp in a given time zone.
+  // https://howardhinnant.github.io/date/tz.html#sys_info
+  date::local_time<milliseconds> timePoint{timestamp};
+  bool isDst = getZonedTime(tz_, timePoint, choose).get_info().save !=
+      std::chrono::minutes(0);
+
+  // Construct the long name for the time zone.
+  // Note that ICU does not have DST information for many time zones prior to
+  // 1970, so it's important to specify it explicitly.
+  icu::UnicodeString longName;
+  tz->getDisplayName(
+      isDst, icu::TimeZone::EDisplayType::LONG, locale, longName);
+
+  // Convert the UnicodeString back to a string and write it out
+  std::string longNameStr;
+  longName.toUTF8String(longNameStr);
+
+  return longNameStr;
+}
 } // namespace facebook::velox::tz

velox/type/tz/TimeZoneMap.h

@@ -160,6 +160,14 @@ class TimeZone {
       milliseconds timestamp,
       TChoose choose = TChoose::kFail) const;
 
+  /// Returns the long name of the time zone for the given timestamp, e.g.
+  /// Pacific Standard Time.  Note that the timestamp is needed for time zones
+  /// that support daylight savings time as the long name will change depending
+  /// on the date (e.g. Pacific Standard Time vs Pacific Daylight Time).
+  std::string getLongName(
+      milliseconds timestamp,
+      TChoose choose = TChoose::kFail) const;
+
  private:
   const date::time_zone* tz_{nullptr};
   const std::chrono::minutes offset_{0};

velox/type/tz/tests/TimeZoneMapTest.cpp

@@ -259,5 +259,29 @@ TEST(TimeZoneMapTest, getShortName) {
   EXPECT_EQ("PST", toShortName("America/Los_Angeles", ts));
 }
 
+TEST(TimeZoneMapTest, getLongName) {
+  auto toLongName = [&](std::string_view name, size_t ts) {
+    const auto* tz = locateZone(name);
+    EXPECT_NE(tz, nullptr);
+    return tz->getLongName(milliseconds{ts});
+  };
+
+  // Test an offset that maps to an actual time zone.
+  EXPECT_EQ("Coordinated Universal Time", toLongName("+00:00", 0));
+
+  // Test offsets that do not map to named time zones.
+  EXPECT_EQ("+00:01", toLongName("+00:01", 0));
+  EXPECT_EQ("-00:01", toLongName("-00:01", 0));
+  EXPECT_EQ("+01:00", toLongName("+01:00", 0));
+  EXPECT_EQ("-01:01", toLongName("-01:01", 0));
+
+  // In "2024-07-25", America/Los_Angeles was in daylight savings time (UTC-07).
+  size_t ts = 1721890800000;
+  EXPECT_EQ("Pacific Daylight Time", toLongName("America/Los_Angeles", ts));
+
+  // In "2024-01-01", it was not (UTC-08).
+  ts = 1704096000000;
+  EXPECT_EQ("Pacific Standard Time", toLongName("America/Los_Angeles", ts));
+}
 } // namespace
 } // namespace facebook::velox::tz