Deprecate implicit coercion of `ActiveSupport::Duration`

Currently `ActiveSupport::Duration` implicitly converts to a seconds
value when used in a calculation except for the explicit examples of
addition and subtraction where the duration is the receiver, e.g:

    >> 2 * 1.day
    => 172800

This results in lots of confusion especially when using durations
with dates because adding/subtracting a value from a date treats
integers as a day and not a second, e.g:

    >> Date.today
    => Wed, 01 Mar 2017
    >> Date.today + 2 * 1.day
    => Mon, 10 Apr 2490

To fix this we're implementing `coerce` so that we can provide a
deprecation warning with the intent of removing the implicit coercion
in Rails 5.2, e.g:

    >> 2 * 1.day
    DEPRECATION WARNING: Implicit coercion of ActiveSupport::Duration
    to a Numeric is deprecated and will raise a TypeError in Rails 5.2.
    => 172800

In Rails 5.2 it will raise `TypeError`, e.g:

    >> 2 * 1.day
    TypeError: ActiveSupport::Duration can't be coerced into Integer

This is the same behavior as with other types in Ruby, e.g:

    >> 2 * "foo"
    TypeError: String can't be coerced into Integer
    >> "foo" * 2
    => "foofoo"

As part of this deprecation add `*` and `/` methods to `AS::Duration`
so that calculations that keep the duration as the receiver work
correctly whether the final receiver is a `Date` or `Time`, e.g:

    >> Date.today
    => Wed, 01 Mar 2017
    >> Date.today + 1.day * 2
    => Fri, 03 Mar 2017

Fixes #27457.

1 files changed, 1 insertions, 1 deletions

diff --git a/actionmailer/test/message_delivery_test.rb b/actionmailer/test/message_delivery_test.rb
index a79d77e1e5..f4c4f43bdc 100644
--- a/actionmailer/test/message_delivery_test.rb
+++ b/actionmailer/test/message_delivery_test.rb
@@ -76,7 +76,7 @@ class MessageDeliveryTest < ActiveSupport::TestCase
 
   test "should enqueue a delivery with a delay" do
     travel_to Time.new(2004, 11, 24, 01, 04, 44) do
-      assert_performed_with(job: ActionMailer::DeliveryJob, at: Time.current.to_f + 600.seconds, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
+      assert_performed_with(job: ActionMailer::DeliveryJob, at: Time.current.to_f + 600, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
         @mail.deliver_later wait: 600.seconds
       end
     end