From 32f215c3014e580e512db5e8772d0deadf3d6497 Mon Sep 17 00:00:00 2001 From: Sean Griffin Date: Tue, 29 Nov 2016 13:02:14 -0500 Subject: Treat combined durations as a single unit Prior to this commit, `3.months - 3.months` would result in a duration that has the "parts" of `[[:months, 3], [:months, -3]]`. This would mean that it was subtly different than `2.months - 2.months`. When applied to a time, the date might actually change if the resulting day doesn't exist however many months in the future, even though in both cases we just wanted to add `0`, which should always be an identity operation. With this change, we now store the parts as a hash, so `3.months - 3.months` is simply stored as `{ months: 0 }`. --- activesupport/test/core_ext/duration_test.rb | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'activesupport/test') diff --git a/activesupport/test/core_ext/duration_test.rb b/activesupport/test/core_ext/duration_test.rb index b7b4a9dd00..26a9ea4aee 100644 --- a/activesupport/test/core_ext/duration_test.rb +++ b/activesupport/test/core_ext/duration_test.rb @@ -345,6 +345,17 @@ class DurationTest < ActiveSupport::TestCase end end + def test_adding_durations_do_not_hold_prior_states + time = Time.parse("Nov 29, 2016") + # If the implementation adds and subtracts 3 months, the + # resulting date would have been in February so the day will + # change to the 29th. + d1 = 3.months - 3.months + d2 = 2.months - 2.months + + assert_equal time + d1, time + d2 + end + private def eastern_time_zone if Gem.win_platform? -- cgit v1.2.3