Fix ActiveSupport::TimeWithZone#in

Previously calls to `in` were being sent to the non-DST aware
method `Time#since` via `method_missing`. It is now aliased to
the DST aware `ActiveSupport::TimeWithZone#+` which handles
transitions across DST boundaries, e.g:

    Time.zone = "US/Eastern"

    t = Time.zone.local(2016,11,6,1)
    # => Sun, 06 Nov 2016 01:00:00 EDT -05:00

    t.in(1.hour)
    # => Sun, 06 Nov 2016 01:00:00 EST -05:00

3 files changed, 51 insertions, 1 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 30985060fd..f840783059 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,22 @@
+*   Fix `ActiveSupport::TimeWithZone#in` across DST boundaries.
+
+    Previously calls to `in` were being sent to the non-DST aware
+    method `Time#since` via `method_missing`. It is now aliased to
+    the DST aware `ActiveSupport::TimeWithZone#+` which handles
+    transitions across DST boundaries, e.g:
+
+        Time.zone = "US/Eastern"
+
+        t = Time.zone.local(2016,11,6,1)
+        # => Sun, 06 Nov 2016 01:00:00 EDT -05:00 
+
+        t.in(1.hour)
+        # => Sun, 06 Nov 2016 01:00:00 EST -05:00 
+
+    Fixes #26580.
+
+    *Thomas Balthazar*
+
 *   Remove unused parameter `options = nil` for `#clear` of
     `ActiveSupport::Cache::Strategy::LocalCache::LocalStore` and
     `ActiveSupport::Cache::Strategy::LocalCache`.
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index f7586efe6a..c35588fbae 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -279,6 +279,7 @@ module ActiveSupport
       end
     end
     alias_method :since, :+
+    alias_method :in, :+
 
     # Returns a new TimeWithZone object that represents the difference between
     # the current object's time and the +other+ time.
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
index 6ab1368e53..e35aa6e154 100644
--- a/activesupport/test/core_ext/time_with_zone_test.rb
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -675,6 +675,10 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Fri, 31 Dec 1999 19:00:01 EST -05:00", @twz.since(1).inspect
   end
 
+  def test_in
+    assert_equal "Fri, 31 Dec 1999 19:00:01 EST -05:00", @twz.in(1).inspect
+  end
+
   def test_ago
     assert_equal "Fri, 31 Dec 1999 18:59:59 EST -05:00", @twz.ago(1).inspect
   end
@@ -688,6 +692,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.advance(years: 1).inspect
     assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.years_since(1).inspect
     assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.since(1.year).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.in(1.year).inspect
     assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", (twz + 1.year).inspect
   end
 
@@ -696,6 +701,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.advance(months: 1).inspect
     assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.months_since(1).inspect
     assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.since(1.month).inspect
+    assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", twz.in(1.month).inspect
     assert_equal "Mon, 28 Feb 2005 00:00:00 EST -05:00", (twz + 1.month).inspect
   end
 
@@ -704,6 +710,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", twz.advance(months: 1).inspect
     assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", twz.months_since(1).inspect
     assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", twz.since(1.month).inspect
+    assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", twz.in(1.month).inspect
     assert_equal "Tue, 29 Feb 2000 00:00:00 EST -05:00", (twz + 1.month).inspect
   end
 
@@ -712,6 +719,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.advance(months: 1).inspect
     assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.months_since(1).inspect
     assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.since(1.month).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.in(1.month).inspect
     assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", (twz + 1.month).inspect
   end
 
@@ -719,9 +727,11 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2006,4,2,1,59,59))
     assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.advance(seconds: 1).inspect
     assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", (twz + 1).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", (twz + 1.second).inspect
     assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.since(1).inspect
     assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.since(1.second).inspect
-    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", (twz + 1.second).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.in(1).inspect
+    assert_equal "Sun, 02 Apr 2006 03:00:00 EDT -04:00", twz.in(1.second).inspect
   end
 
   def test_advance_1_day_across_spring_dst_transition
@@ -730,8 +740,10 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     # When we advance 1 day, we want to end up at the same time on the next day
     assert_equal "Sun, 02 Apr 2006 10:30:00 EDT -04:00", twz.advance(days: 1).inspect
     assert_equal "Sun, 02 Apr 2006 10:30:00 EDT -04:00", twz.since(1.days).inspect
+    assert_equal "Sun, 02 Apr 2006 10:30:00 EDT -04:00", twz.in(1.days).inspect
     assert_equal "Sun, 02 Apr 2006 10:30:00 EDT -04:00", (twz + 1.days).inspect
     assert_equal "Sun, 02 Apr 2006 10:30:01 EDT -04:00", twz.since(1.days + 1.second).inspect
+    assert_equal "Sun, 02 Apr 2006 10:30:01 EDT -04:00", twz.in(1.days + 1.second).inspect
     assert_equal "Sun, 02 Apr 2006 10:30:01 EDT -04:00", (twz + 1.days + 1.second).inspect
   end
 
@@ -753,12 +765,16 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", (twz + 86400.seconds).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.since(86400).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.since(86400.seconds).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.in(86400).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.in(86400.seconds).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.advance(seconds: 86400).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", (twz + 1440.minutes).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.since(1440.minutes).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.in(1440.minutes).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.advance(minutes: 1440).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", (twz + 24.hours).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.since(24.hours).inspect
+    assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.in(24.hours).inspect
     assert_equal "Sun, 02 Apr 2006 11:30:00 EDT -04:00", twz.advance(hours: 24).inspect
   end
 
@@ -785,8 +801,10 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     # When we advance 1 day, we want to end up at the same time on the next day
     assert_equal "Sun, 29 Oct 2006 10:30:00 EST -05:00", twz.advance(days: 1).inspect
     assert_equal "Sun, 29 Oct 2006 10:30:00 EST -05:00", twz.since(1.days).inspect
+    assert_equal "Sun, 29 Oct 2006 10:30:00 EST -05:00", twz.in(1.days).inspect
     assert_equal "Sun, 29 Oct 2006 10:30:00 EST -05:00", (twz + 1.days).inspect
     assert_equal "Sun, 29 Oct 2006 10:30:01 EST -05:00", twz.since(1.days + 1.second).inspect
+    assert_equal "Sun, 29 Oct 2006 10:30:01 EST -05:00", twz.in(1.days + 1.second).inspect
     assert_equal "Sun, 29 Oct 2006 10:30:01 EST -05:00", (twz + 1.days + 1.second).inspect
   end
 
@@ -808,12 +826,16 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", (twz + 86400.seconds).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.since(86400).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.since(86400.seconds).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.in(86400).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.in(86400.seconds).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.advance(seconds: 86400).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", (twz + 1440.minutes).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.since(1440.minutes).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.in(1440.minutes).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.advance(minutes: 1440).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", (twz + 24.hours).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.since(24.hours).inspect
+    assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.in(24.hours).inspect
     assert_equal "Sun, 29 Oct 2006 09:30:00 EST -05:00", twz.advance(hours: 24).inspect
   end
 
@@ -839,6 +861,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", twz.advance(weeks: 1).inspect
     assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", twz.weeks_since(1).inspect
     assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", twz.since(1.week).inspect
+    assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", twz.in(1.week).inspect
     assert_equal "Sat, 08 Apr 2006 10:30:00 EDT -04:00", (twz + 1.week).inspect
   end
 
@@ -855,6 +878,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", twz.advance(weeks: 1).inspect
     assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", twz.weeks_since(1).inspect
     assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", twz.since(1.week).inspect
+    assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", twz.in(1.week).inspect
     assert_equal "Sat, 04 Nov 2006 10:30:00 EST -05:00", (twz + 1.week).inspect
   end
 
@@ -871,6 +895,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", twz.advance(months: 1).inspect
     assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", twz.months_since(1).inspect
     assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", twz.since(1.month).inspect
+    assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", twz.in(1.month).inspect
     assert_equal "Mon, 01 May 2006 10:30:00 EDT -04:00", (twz + 1.month).inspect
   end
 
@@ -887,6 +912,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", twz.advance(months: 1).inspect
     assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", twz.months_since(1).inspect
     assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", twz.since(1.month).inspect
+    assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", twz.in(1.month).inspect
     assert_equal "Tue, 28 Nov 2006 10:30:00 EST -05:00", (twz + 1.month).inspect
   end
 
@@ -902,6 +928,8 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2008,2,15,10,30))
     assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", twz.advance(years: 1).inspect
     assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", twz.years_since(1).inspect
+    assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", twz.since(1.year).inspect
+    assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", twz.in(1.year).inspect
     assert_equal "Sun, 15 Feb 2009 10:30:00 EST -05:00", (twz + 1.year).inspect
     assert_equal "Thu, 15 Feb 2007 10:30:00 EST -05:00", twz.advance(years: -1).inspect
     assert_equal "Thu, 15 Feb 2007 10:30:00 EST -05:00", twz.years_ago(1).inspect
@@ -912,6 +940,8 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     twz = ActiveSupport::TimeWithZone.new(nil, @time_zone, Time.utc(2008,7,15,10,30))
     assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", twz.advance(years: 1).inspect
     assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", twz.years_since(1).inspect
+    assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", twz.since(1.year).inspect
+    assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", twz.in(1.year).inspect
     assert_equal "Wed, 15 Jul 2009 10:30:00 EDT -04:00", (twz + 1.year).inspect
     assert_equal "Sun, 15 Jul 2007 10:30:00 EDT -04:00", twz.advance(years: -1).inspect
     assert_equal "Sun, 15 Jul 2007 10:30:00 EDT -04:00", twz.years_ago(1).inspect