time diff wrong calculation?

[mtricolici]

# cat test.rb 
#!/usr/bin/env ruby
require 'date'
require 'time_difference'

now = Time.now.utc
puts "now is #{now}"

backup_date = DateTime.strptime('2017-06-28-000001', '%Y-%m-%d-%H%M%S').utc
puts "backup_date is #{backup_date}"

h = TimeDifference.between(backup_date, now).in_hours
puts "...time diff in hours=#{h}"

# ./test.rb 
now is 2017-06-28 07:54:20 UTC
backup_date is 2017-06-28 00:00:01 UTC
...time diff in hours=102454424.73

# ruby -v
ruby 2.3.4p301 (2017-03-30 revision 58214) [x86_64-linux-musl]
time_difference (0.5.0)

[mtricolici]

another test

ruby 2.3.3p222
time_difference (0.5.0)

#!/usr/bin/env ruby
require 'date'
require 'time_difference'

now = DateTime.now.utc
puts "now is #{now}. class=#{now.class}"

backup_date = DateTime.strptime('2017-06-28-000001', '%Y-%m-%d-%H%M%S').utc
puts "backup_date is #{backup_date}. class=#{backup_date.class}"

h = TimeDifference.between(backup_date, now).in_hours
puts "...time diff in hours=#{h}"

now is 2017-06-28 08:26:35 UTC. class=Time
backup_date is 2017-06-28 00:00:01 UTC. class=Time
...time diff in hours=109421732.92

[mtricolici]

works fine in ruby 2.2. and 2.4. (issue in 2.3.1 & 2.3.4)

[bodsch]

the same here, but with ruby 2.4.1

here works ruby 2.3.0

/ # ruby --version
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux-musl]

/ # gem list time_difference

*** LOCAL GEMS ***

time_difference (0.5.0)

irb(main):024:0* now = DateTime.now.utc
=> 2017-06-29 13:56:31 UTC
irb(main):025:0> last = Time.at( 1506470400000 / 1000 )
=> 2017-09-27 00:00:00 +0000
irb(main):026:0> puts "now is #{now}. class=#{now.class}"
now is 2017-06-29 13:56:31 UTC. class=Time
=> nil
irb(main):027:0> puts "last is #{last}. class=#{last.class}"
last is 2017-09-27 00:00:00 +0000. class=Time
=> nil
irb(main):028:0> h = TimeDifference.between(now,last).in_each_component
=> {:years=>243797379089759.7, :months=>21942621712.53, :weeks=>4672461867467.01, :days=>667494552495.29, :hours=>27812273020.64, :minutes=>463537883.68, :seconds=>7725631.394621372}

[BLauris]

I got this issue on all of these ruby versions 2.3.1, 2.3.3, 2.3.4 and 2.4.1.

[aviflax]

I just encountered this problem as well, but in my case it doesn’t appear to have anything to do with the runtime version. Rather, I encountered the problem while upgrading dependencies. I managed to narrow it down to ActiveSupport. For whatever reason, when I use ActiveSupport 5.1.1 it works fine, but when I use 5.1.2 it breaks. I checked the release notes for 5.1.2 and they only describe two changes. One of them, however, is “Fix implicit coercion calculations with scalars and durations” — so that might be the culprit.

I have not dug further than that, because personally I’d rather just stick with 5.1.1 for now rather than take more time to debug this.

HTH!

[aviflax]

Oh and also I noticed that #31 might address this. Not entirely sure.

[fadynaffa3]

@aviflax your 100% right the issue happened when I updated rails to 5.1.2 as 5.1.1 had no problems.

• ActiveSupport 5.1.1

  (((Time.now + 2.hours) - Time.now) / 1.hours).round
  = 2

• ActiveSupport 5.1.2

  (((Time.now + 2.hours) - Time.now) / 1.hours).round
  = 25920000

[Jacotb]

Can confirm. Rails 5.1.2 changed the behaviour of x / 1.hour. It now returns x.hours rather than (x/3600).hours.

2.4.0 :033 > TimeDifference.between(DateTime.now, DateTime.now - 1.week).in_seconds
 => 604799.9996852875 
2.4.0 :034 > TimeDifference.between(DateTime.now, DateTime.now - 1.week).in_hours
 => 2177279998.97 

[fadynaffa3]

You can find the change here https://github.com/rails/rails/blob/v5.1.2/activesupport/CHANGELOG.md

• Fix implicit coercion calculations with scalars and durations

  Previously calculations where the scalar is first would be converted to a duration of seconds but this causes issues with dates being converted to times, e.g:

  Time.zone = "Beijing"           # => Asia/Shanghai
  date = Date.civil(2017, 5, 20)  # => Mon, 20 May 2017
  2 * 1.day                       # => 172800 seconds
  date + 2 * 1.day                # => Mon, 22 May 2017 00:00:00 CST +08:00

  Now the ActiveSupport::Duration::Scalar calculation methods will try to maintain the part structure of the duration where possible, e.g:

  Time.zone = "Beijing"           # => Asia/Shanghai
  date = Date.civil(2017, 5, 20)  # => Mon, 20 May 2017
  2 * 1.day                       # => 2 days
  date + 2 * 1.day                # => Mon, 22 May 2017

  Fixes #29160, #28970.

  Andrew White

[conroywhitney]

Thank you! This helped me troubleshoot the issue much quicker than I could have on my own.

BTW, activesupport v5.1.3 is out now and fixes this issue. bundle update rails should do the trick.

[tmlee]

Thanks guys. Verifying that the library continues to work as expected with the latest version of ActiveSupport. Will re-open if anyone is still facing issues for this one