Update to TZInfo v2.0.0

Co-authored-by: Jared Beck <jared@jaredbeck.com>
Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>

Gemfile.lock

@@ -73,7 +73,7 @@ PATH
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (~> 5.1)
-      tzinfo (~> 1.1)
+      tzinfo (~> 2.0)
       zeitwerk (~> 2.2, >= 2.2.2)
     rails (6.1.0.alpha)
       actioncable (= 6.1.0.alpha)
@@ -490,14 +490,12 @@ GEM
       eventmachine (~> 1.0, >= 1.0.4)
       rack (>= 1, < 3)
     thor (1.0.1)
-    thread_safe (0.3.6)
-    thread_safe (0.3.6-java)
     tilt (2.0.10)
     turbolinks (5.2.1)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
-    tzinfo (1.2.6)
-      thread_safe (~> 0.1)
+    tzinfo (2.0.0)
+      concurrent-ruby (~> 1.0)
     tzinfo-data (1.2019.3)
       tzinfo (>= 1.0.0)
     uber (0.1.0)

activesupport/CHANGELOG.md

@@ -1,3 +1,16 @@
+*   Update to TZInfo v2.0.0.
+
+    This changes the output of `ActiveSupport::TimeZone.utc_to_local`, but
+    can be controlled with the
+    `Rails.application.config.active_support.utc_to_local_returns_utc_offset_times` config.
+
+    New Rails 6.1 apps have it enabled by default, existing apps can upgrade
+    via the config in config/initializers/new_framework_defaults_6_1.rb
+
+    See the `utc_to_local_returns_utc_offset_times` documentation for details.
+
+    *Phil Ross and Jared Beck*
+
 *   [Breaking change] `ActiveSupport::Callbacks#halted_callback_hook` now receive a 2nd argument:
 
     `ActiveSupport::Callbacks#halted_callback_hook` now receive the name of the callback

activesupport/activesupport.gemspec

@@ -34,7 +34,7 @@ Gem::Specification.new do |s|
   # https://edgeguides.rubyonrails.org/security.html#dependency-management-and-cves
 
   s.add_dependency "i18n",            ">= 1.6", "< 2"
-  s.add_dependency "tzinfo",          "~> 1.1"
+  s.add_dependency "tzinfo",          "~> 2.0"
   s.add_dependency "minitest",        "~> 5.1"
   s.add_dependency "concurrent-ruby", "~> 1.0", ">= 1.0.2"
   s.add_dependency "zeitwerk",        "~> 2.2", ">= 2.2.2"

activesupport/lib/active_support.rb

@@ -95,6 +95,14 @@ module ActiveSupport
   def self.to_time_preserves_timezone=(value)
     DateAndTime::Compatibility.preserve_timezone = value
   end
+
+  def self.utc_to_local_returns_utc_offset_times
+    DateAndTime::Compatibility.utc_to_local_returns_utc_offset_times
+  end
+
+  def self.utc_to_local_returns_utc_offset_times=(value)
+    DateAndTime::Compatibility.utc_to_local_returns_utc_offset_times = value
+  end
 end
 
 autoload :I18n, "active_support/i18n"

activesupport/lib/active_support/core_ext/date_and_time/compatibility.rb

@@ -12,5 +12,20 @@ module DateAndTime
     # this behavior, but new apps will have an initializer that sets
     # this to true, because the new behavior is preferred.
     mattr_accessor :preserve_timezone, instance_writer: false, default: false
+
+    # Change the output of <tt>ActiveSupport::TimeZone.utc_to_local</tt>.
+    #
+    # When `true`, it returns local times with an UTC offset, with `false` local
+    # times are returned as UTC.
+    #
+    #   # Given this zone:
+    #   zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
+    #
+    #   # With `utc_to_local_returns_utc_offset_times = false`, local time is converted to UTC:
+    #   zone.utc_to_local(Time.utc(2000, 1)) # => 1999-12-31 19:00:00 UTC
+    #
+    #   # With `utc_to_local_returns_utc_offset_times = true`, local time is returned with UTC offset:
+    #   zone.utc_to_local(Time.utc(2000, 1)) # => 1999-12-31 19:00:00 -0500
+    mattr_accessor :utc_to_local_returns_utc_offset_times, instance_writer: false, default: false
   end
 end

activesupport/lib/active_support/time_with_zone.rb

@@ -57,12 +57,12 @@ module ActiveSupport
 
     # Returns a <tt>Time</tt> instance that represents the time in +time_zone+.
     def time
-      @time ||= period.to_local(@utc)
+      @time ||= incorporate_utc_offset(@utc, utc_offset)
     end
 
     # Returns a <tt>Time</tt> instance of the simultaneous time in the UTC timezone.
     def utc
-      @utc ||= period.to_utc(@time)
+      @utc ||= incorporate_utc_offset(@time, -utc_offset)
     end
     alias_method :comparable_time, :utc
     alias_method :getgm, :utc
@@ -104,13 +104,13 @@ module ActiveSupport
     #   Time.zone = 'Eastern Time (US & Canada)'    # => 'Eastern Time (US & Canada)'
     #   Time.zone.now.utc?                          # => false
     def utc?
-      period.offset.abbreviation == :UTC || period.offset.abbreviation == :UCT
+      zone == "UTC" || zone == "UCT"
     end
     alias_method :gmt?, :utc?
 
     # Returns the offset from current time to UTC time in seconds.
     def utc_offset
-      period.utc_total_offset
+      period.observed_utc_offset
     end
     alias_method :gmt_offset, :utc_offset
     alias_method :gmtoff, :utc_offset
@@ -132,7 +132,7 @@ module ActiveSupport
     #   Time.zone = 'Eastern Time (US & Canada)'   # => "Eastern Time (US & Canada)"
     #   Time.zone.now.zone # => "EST"
     def zone
-      period.zone_identifier.to_s
+      period.abbreviation
     end
 
     # Returns a string of the object's date, time, zone, and offset from UTC.
@@ -524,6 +524,16 @@ module ActiveSupport
     end
 
     private
+      SECONDS_PER_DAY = 86400
+
+      def incorporate_utc_offset(time, offset)
+        if time.kind_of?(Date)
+          time + Rational(offset, SECONDS_PER_DAY)
+        else
+          time + offset
+        end
+      end
+
       def get_period_and_ensure_valid_local_time(period)
         # we don't want a Time.local instance enforcing its own DST rules as well,
         # so transfer time values to a utc constructor if necessary

activesupport/lib/active_support/values/time_zone.rb

@@ -203,7 +203,7 @@ module ActiveSupport
       end
 
       def find_tzinfo(name)
-        TZInfo::Timezone.new(MAPPING[name] || name)
+        TZInfo::Timezone.get(MAPPING[name] || name)
       end
 
       alias_method :create, :new
@@ -273,7 +273,7 @@ module ActiveSupport
                 memo
               end
             else
-              create(tz_id, nil, TZInfo::Timezone.new(tz_id))
+              create(tz_id, nil, TZInfo::Timezone.get(tz_id))
             end
           end.sort!
         end
@@ -302,11 +302,7 @@ module ActiveSupport
 
     # Returns the offset of this time zone from UTC in seconds.
     def utc_offset
-      if @utc_offset
-        @utc_offset
-      else
-        tzinfo.current_period.utc_offset if tzinfo && tzinfo.current_period
-      end
+      @utc_offset || tzinfo&.current_period&.base_utc_offset
     end
 
     # Returns a formatted string of the offset from UTC, or an alternative
@@ -507,10 +503,17 @@ module ActiveSupport
     end
 
     # Adjust the given time to the simultaneous time in the time zone
-    # represented by +self+. Returns a Time.utc() instance -- if you want an
-    # ActiveSupport::TimeWithZone instance, use Time#in_time_zone() instead.
+    # represented by +self+. Returns a local time with the appropriate offset
+    # -- if you want an ActiveSupport::TimeWithZone instance, use
+    # Time#in_time_zone() instead.
+    #
+    # As of tzinfo 2, utc_to_local returns a Time with a non-zero utc_offset.
+    # See the `utc_to_local_returns_utc_offset_times` config for more info.
     def utc_to_local(time)
-      tzinfo.utc_to_local(time)
+      tzinfo.utc_to_local(time).yield_self do |t|
+        ActiveSupport.utc_to_local_returns_utc_offset_times ?
+          t : Time.utc(t.year, t.month, t.day, t.hour, t.min, t.sec, t.sec_fraction)
+      end
     end
 
     # Adjust the given time to the simultaneous time in UTC. Returns a

activesupport/test/time_zone_test.rb

@@ -10,8 +10,15 @@ class TimeZoneTest < ActiveSupport::TestCase
 
   def test_utc_to_local
     zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
-    assert_equal Time.utc(1999, 12, 31, 19), zone.utc_to_local(Time.utc(2000, 1)) # standard offset -0500
-    assert_equal Time.utc(2000, 6, 30, 20), zone.utc_to_local(Time.utc(2000, 7)) # dst offset -0400
+
+    with_utc_to_local_returns_utc_offset_times false do
+      assert_equal Time.utc(1999, 12, 31, 19), zone.utc_to_local(Time.utc(2000, 1)) # standard offset -0500
+      assert_equal Time.utc(2000, 6, 30, 20), zone.utc_to_local(Time.utc(2000, 7)) # dst offset -0400
+    end
+    with_utc_to_local_returns_utc_offset_times true do
+      assert_equal Time.new(1999, 12, 31, 19, 0, 0, -18000), zone.utc_to_local(Time.utc(2000, 1)) # standard offset -0500
+      assert_equal Time.new(2000, 6, 30, 20, 0, 0, -14400), zone.utc_to_local(Time.utc(2000, 7)) # dst offset -0400
+    end
   end
 
   def test_local_to_utc
@@ -22,7 +29,7 @@ class TimeZoneTest < ActiveSupport::TestCase
 
   def test_period_for_local
     zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
-    assert_instance_of TZInfo::TimezonePeriod, zone.period_for_local(Time.utc(2000))
+    assert_kind_of TZInfo::TimezonePeriod, zone.period_for_local(Time.utc(2000))
   end
 
   ActiveSupport::TimeZone::MAPPING.each_key do |name|
@@ -54,7 +61,7 @@ class TimeZoneTest < ActiveSupport::TestCase
 
     define_method("test_utc_offset_for_#{name}") do
       period = zone.tzinfo.current_period
-      assert_equal period.utc_offset, zone.utc_offset
+      assert_equal period.base_utc_offset, zone.utc_offset
     end
   end
 
@@ -96,8 +103,15 @@ class TimeZoneTest < ActiveSupport::TestCase
     zone = ActiveSupport::TimeZone["America/Montevideo"]
     assert_equal ActiveSupport::TimeZone, zone.class
     assert_equal zone.object_id, ActiveSupport::TimeZone["America/Montevideo"].object_id
-    assert_equal Time.utc(2010, 1, 31, 22), zone.utc_to_local(Time.utc(2010, 2)) # daylight saving offset -0200
-    assert_equal Time.utc(2010, 3, 31, 21), zone.utc_to_local(Time.utc(2010, 4)) # standard offset -0300
+
+    with_utc_to_local_returns_utc_offset_times false do
+      assert_equal Time.utc(2010, 1, 31, 22), zone.utc_to_local(Time.utc(2010, 2)) # daylight saving offset -0200
+      assert_equal Time.utc(2010, 3, 31, 21), zone.utc_to_local(Time.utc(2010, 4)) # standard offset -0300
+    end
+    with_utc_to_local_returns_utc_offset_times true do
+      assert_equal Time.new(2010, 1, 31, 22, 0, 0, -7200), zone.utc_to_local(Time.utc(2010, 2)) # daylight saving offset -0200
+      assert_equal Time.new(2010, 3, 31, 21, 0, 0, -10800), zone.utc_to_local(Time.utc(2010, 4)) # standard offset -0300
+    end
   end
 
   def test_today

activesupport/test/time_zone_test_helpers.rb

@@ -36,4 +36,12 @@ module TimeZoneTestHelpers
     ActiveSupport::TimeZone::MAPPING.clear
     ActiveSupport::TimeZone::MAPPING.merge!(old_mappings)
   end
+
+  def with_utc_to_local_returns_utc_offset_times(value)
+    old_tzinfo2_format = ActiveSupport.utc_to_local_returns_utc_offset_times
+    ActiveSupport.utc_to_local_returns_utc_offset_times = value
+    yield
+  ensure
+    ActiveSupport.utc_to_local_returns_utc_offset_times = old_tzinfo2_format
+  end
 end

railties/lib/rails/application/configuration.rb

@@ -178,6 +178,10 @@ module Rails
           if respond_to?(:action_dispatch)
             action_dispatch.cookies_same_site_protection = :lax
           end
+
+          if respond_to?(:active_support)
+            active_support.utc_to_local_returns_utc_offset_times = true
+          end
         else
           raise "Unknown version #{target_version.to_s.inspect}"
         end

railties/lib/rails/generators/rails/app/templates/config/initializers/new_framework_defaults_6_1.rb.tt

@@ -21,3 +21,7 @@
 # This change is not backwards compatible with earlier Rails versions.
 # It's best enabled when your entire app is migrated and stable on 6.1.
 # Rails.application.config.action_dispatch.cookies_same_site_protection = :lax
+
+# Specify whether `ActiveSupport::TimeZone.utc_to_local` returns a time with an
+# UTC offset or a UTC time.
+# Rails.application.config.active_support.utc_to_local_returns_utc_offset_times = true

railties/test/application/configuration_test.rb

@@ -2295,6 +2295,15 @@ module ApplicationTests
       assert_equal :lax, Rails.application.config.action_dispatch.cookies_same_site_protection
     end
 
+    test "enables utc_to_local_returns_utc_offset_times by default" do
+      remove_from_config '.*config\.load_defaults.*\n'
+      add_to_config 'config.load_defaults "6.1"'
+
+      app "development"
+
+      assert_equal true, Rails.application.config.active_support.utc_to_local_returns_utc_offset_times
+    end
+
     test "ActiveStorage.queues[:analysis] is :active_storage_analysis by default" do
       app "development"