Deprecate implicit coercion of `ActiveSupport::Duration` #28204

pixeltrix · 2017-02-27T18:33:48Z

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.

pixeltrix · 2017-02-27T18:36:03Z

actionview/test/template/date_helper_test.rb

@@ -832,7 +832,7 @@ def test_select_date

  def test_select_date_with_too_big_range_between_start_year_and_end_year
    assert_raise(ArgumentError) { select_date(Time.mktime(2003, 8, 16), start_year: 2000, end_year: 20000, prefix: "date[first]", order: [:month, :day, :year]) }
-    assert_raise(ArgumentError) { select_date(Time.mktime(2003, 8, 16), start_year: Date.today.year - 100.years, end_year: 2000, prefix: "date[first]", order: [:month, :day, :year]) }
+    assert_raise(ArgumentError) { select_date(Time.mktime(2003, 8, 16), start_year: 100, end_year: 2000, prefix: "date[first]", order: [:month, :day, :year]) }


This test exhibits the exact problem I'm trying to fix - Date.today.year - 100.years gives -3155757983.0 and not the probable intent of 1917.

@dhh this is the problem I'm trying to solve with the deprecation - complete misunderstanding of how durations work.

rafaelfranca · 2017-02-28T23:07:49Z

activesupport/CHANGELOG.md

@@ -1,3 +1,21 @@
+*   Deprecate implicit coercion of `ActiveSupport::Duration`


This changelog is confusion. What are the cases where an implicit coercion is made?

Better now?

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.

pixeltrix · 2017-03-15T08:21:56Z

actionmailer/test/message_delivery_test.rb

@@ -76,7 +76,7 @@ def test_should_enqueue_and_run_correctly_in_activejob

  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


@dhh this has now been changed to Time.current + 600.seconds which it what it should've been in the first place. Also changed another test to Time.current + 1.hour instead of Time.now.to_f + 3600.

Cools. I would even go with Time.current + 10.minutes. That's the wonder of these aliases. You get to pick the scale that makes the most sense.

pixeltrix · 2017-03-15T08:31:03Z

activesupport/lib/active_support/cache/mem_cache_store.rb

@@ -156,7 +156,7 @@ def write_entry(key, entry, options)
          expires_in = options[:expires_in].to_i
          if expires_in > 0 && !options[:raw]
            # Set the memcache expire a few minutes in the future to support race condition ttls on read
-            expires_in += 5.minutes
+            expires_in += 300


This change stems from the to_i - the memcache client expects an integer for expires_in. It could be rewritten to use 5.minutes as the receiver but I thought creating an object was wasteful this deep inside the caching code.

Unless we pin this as a performance bottleneck, I would always go for the clearer code. IMO, 5.minutes is much clearer than 300. This is where I really don't like to manually apply .to_i. But I could live with an alias like expires_in += 5.minutes.in_seconds.

In #28204 we deprecated implicit conversion of durations to a numeric which represented the number of seconds in the duration because of unwanted side effects with calculations on durations and dates. This unfortunately had the side effect of forcing a explicit cast when configuring third-party libraries like expiration in Redis, e.g: redis.expire("foo", 5.minutes) To work around this we've removed the deprecation and added a private class that wraps the numeric and can perform calculation involving durations and ensure that they remain a duration irrespective of the order of operations.

pixeltrix commented Feb 27, 2017

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rafaelfranca reviewed Feb 28, 2017

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rafaelfranca modified the milestones: 5.0.x, 5.1.0 Feb 28, 2017

pixeltrix force-pushed the deprecate-implicit-coercion-of-durations branch from 6719f0b to d8430a3 Compare March 1, 2017 10:17

pixeltrix force-pushed the deprecate-implicit-coercion-of-durations branch from d8430a3 to 75924c4 Compare March 2, 2017 08:00

pixeltrix merged commit c9bc4de into master Mar 3, 2017

pixeltrix deleted the deprecate-implicit-coercion-of-durations branch March 3, 2017 10:48

maclover7 added the activesupport label Mar 5, 2017

pixeltrix commented Mar 15, 2017

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pixeltrix mentioned this pull request Mar 15, 2017

Remove implicit coercion deprecation of durations #28425

Merged

pixeltrix added a commit that referenced this pull request Mar 15, 2017

Restore 5.minutes changed in #28204

99dedd8

pixeltrix added a commit that referenced this pull request Mar 15, 2017

Restore 5.minutes changed in #28204

de5eb9e

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Deprecate implicit coercion of `ActiveSupport::Duration` #28204

Deprecate implicit coercion of `ActiveSupport::Duration` #28204

pixeltrix commented Feb 27, 2017 •

edited

pixeltrix Feb 27, 2017

pixeltrix Mar 15, 2017

rafaelfranca Feb 28, 2017

pixeltrix Mar 1, 2017

pixeltrix Mar 15, 2017

dhh Mar 15, 2017

pixeltrix Mar 15, 2017

dhh Mar 15, 2017

		@@ -1,3 +1,21 @@
		* Deprecate implicit coercion of `ActiveSupport::Duration`

Deprecate implicit coercion of ActiveSupport::Duration #28204

Deprecate implicit coercion of ActiveSupport::Duration #28204

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pixeltrix commented Feb 27, 2017 • edited

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Deprecate implicit coercion of `ActiveSupport::Duration` #28204

Deprecate implicit coercion of `ActiveSupport::Duration` #28204

pixeltrix commented Feb 27, 2017 •

edited