#next_time breaks on DST end #97

trafium · 2024-03-25T15:32:03Z

Issue description

According to https://www.timeanddate.com/time/change/estonia?year=2012
In Estonia, 2012 DST ended on October 28 after 03:59 (EEST) clock turned backward to 03:00 (EET).
Some evidence confirming this when working with Time class:

irb(main):030> Time.parse("2012-10-28 03:00:00 Europe/Tallinn")
=> 2012-10-28 03:00:00 +0200
irb(main):031> Time.parse("2012-10-28 02:00:00 Europe/Tallinn") + 60.minutes
=> 2012-10-28 03:00:00 +0300
irb(main):032> Time.parse("2012-10-28 02:00:00 Europe/Tallinn")
=> 2012-10-28 02:00:00 +0300
irb(main):033> Time.parse("2012-10-28 02:00:00 Europe/Tallinn") + 60.minutes
=> 2012-10-28 03:00:00 +0300
irb(main):034> Time.parse("2012-10-28 02:00:00 Europe/Tallinn") + 119.minutes
=> 2012-10-28 03:59:00 +0300
irb(main):035> Time.parse("2012-10-28 02:00:00 Europe/Tallinn") + 120.minutes
=> 2012-10-28 03:00:00 +0200
irb(main):036> Time.parse("2012-10-28 02:00:00 Europe/Tallinn").zone
=> "EEST"
irb(main):037> (Time.parse("2012-10-28 02:00:00 Europe/Tallinn") + 120.minutes).zone
=> "EET"

But Fugit::Cron breaks on an attempt to calculate next time from cron */1 * * * * starting from 03:00:00 EEST:

irb(main):044> Fugit::Cron.parse("*/1 * * * *").next_time(Time.parse("2012-10-28 02:59:00 EEST"))
=> #<EtOrbi::EoTime:0x000000010884ac98 @rday=nil, @rweek=nil, @seconds=1351382400.0, @time=nil, @zone=#<TZInfo::DataTimezone: Etc/UTC>>

irb(main):045> Fugit::Cron.parse("*/1 * * * *").next_time(Time.parse("2012-10-28 02:59:00 EEST") + 1.minute)
/Users/traf/.rbenv/versions/3.2.3/lib/ruby/gems/3.2.0/gems/et-orbi-1.2.11/lib/et-orbi/time.rb:82:in `initialize': Cannot determine timezone from "EEST" (ArgumentError)
(secs:1351382400.0,utc~:"2012-10-28 00:00:00.0",ltz~:"UTC")
(etz:nil,tnz:"EET",tziv:"2.0.6",tzidv:"1.2024.1",rv:"3.2.3",rp:"arm64-darwin23",win:false,rorv:"7.1.3.2",astz:[ActiveSupport::TimeZone, "Etc/UTC"],eov:"1.2.11",eotnz:#<TZInfo::DataTimezone: Etc/UTC>,eotnfz:"+0000",eotlzn:"Etc/UTC",eotnfZ:"UTC",
debian:nil,centos:nil,osx:"zoneinfo/Europe/Tallinn")
Try setting `ENV['TZ'] = 'Continent/City'` in your script (see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)

irb(main):046> Fugit::Cron.parse("*/1 * * * *").next_time(Time.parse("2012-10-28 03:00:00 EEST"))
/Users/traf/.rbenv/versions/3.2.3/lib/ruby/gems/3.2.0/gems/et-orbi-1.2.11/lib/et-orbi/time.rb:82:in `initialize': Cannot determine timezone from "EEST" (ArgumentError)
(secs:1351382400.0,utc~:"2012-10-28 00:00:00.0",ltz~:"UTC")
(etz:nil,tnz:"EET",tziv:"2.0.6",tzidv:"1.2024.1",rv:"3.2.3",rp:"arm64-darwin23",win:false,rorv:"7.1.3.2",astz:[ActiveSupport::TimeZone, "Etc/UTC"],eov:"1.2.11",eotnz:#<TZInfo::DataTimezone: Etc/UTC>,eotnfz:"+0000",eotlzn:"Etc/UTC",eotnfZ:"UTC",
debian:nil,centos:nil,osx:"zoneinfo/Europe/Tallinn")
Try setting `ENV['TZ'] = 'Continent/City'` in your script (see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)

irb(main):047> Fugit::Cron.parse("*/1 * * * *").next_time(Time.parse("2012-10-28 02:59:00 Europe/Tallinn") + 1.minute)
/Users/traf/.rbenv/versions/3.2.3/lib/ruby/gems/3.2.0/gems/et-orbi-1.2.11/lib/et-orbi/time.rb:82:in `initialize': Cannot determine timezone from "EEST" (ArgumentError)
(secs:1351382400.0,utc~:"2012-10-28 00:00:00.0",ltz~:"UTC")
(etz:nil,tnz:"EET",tziv:"2.0.6",tzidv:"1.2024.1",rv:"3.2.3",rp:"arm64-darwin23",win:false,rorv:"7.1.3.2",astz:[ActiveSupport::TimeZone, "Etc/UTC"],eov:"1.2.11",eotnz:#<TZInfo::DataTimezone: Etc/UTC>,eotnfz:"+0000",eotlzn:"Etc/UTC",eotnfZ:"UTC",
debian:nil,centos:nil,osx:"zoneinfo/Europe/Tallinn")
Try setting `ENV['TZ'] = 'Continent/City'` in your script (see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)

How to reproduce

The simplest piece of code that reproduces the issue:

require 'fugit'
Fugit::Cron.parse("*/1 * * * *").next_time(Time.parse("2012-10-28 03:00:00 EEST"))

Error and error backtrace (if any)

/Users/traf/.rbenv/versions/3.2.3/lib/ruby/gems/3.2.0/gems/et-orbi-1.2.11/lib/et-orbi/time.rb:82:in `initialize': Cannot determine timezone from "EEST" (ArgumentError)
(secs:1351382400.0,utc~:"2012-10-28 00:00:00.0",ltz~:"UTC")
(etz:nil,tnz:"EET",tziv:"2.0.6",tzidv:"1.2024.1",rv:"3.2.3",rp:"arm64-darwin23",win:false,rorv:"7.1.3.2",astz:[ActiveSupport::TimeZone, "Etc/UTC"],eov:"1.2.11",eotnz:#<TZInfo::DataTimezone: Etc/UTC>,eotnfz:"+0000",eotlzn:"Etc/UTC",eotnfZ:"UTC",
debian:nil,centos:nil,osx:"zoneinfo/Europe/Tallinn")
Try setting `ENV['TZ'] = 'Continent/City'` in your script (see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)

Expected behaviour

Not get error thrown

Given:

Fugit::Cron.parse("*/1 * * * *").next_time(Time.parse("2012-10-28 03:00:00 EEST")).to_t

Output: 2012-10-28 03:01:00 +0300 (+0300 signifies EEST)

Given:

Fugit::Cron.parse("*/1 * * * *").next_time(Time.parse("2012-10-28 03:59:00 EEST")).to_t

Output: 2012-10-28 03:00:00 +0200 (+0200 signifies EET)

Context

Darwin Dmitris-MacBook-Air.local 23.3.0 Darwin Kernel Version 23.3.0: Wed Dec 20 21:30:27 PST 2023; root:xnu-10002.81.5~7/RELEASE_ARM64_T8103 arm64
ruby 3.2.3 (2024-01-18 revision 52bb2ac0a6) [arm64-darwin23]
[:env_tz, nil]
(secs:1711380674.477833,utc~:"2024-03-25 15:31:14.4778330326080322",ltz~:"EET")
(etz:nil,tnz:"EET",tziv:"2.0.6",tzidv:"1.2024.1",rv:"3.2.3",rp:"arm64-darwin23",win:false,rorv:nil,astz:nil,eov:"1.2.11",eotnz:#<TZInfo::TimezoneProxy: Africa/Cairo>,eotnfz:"+0200",eotlzn:"Africa/Cairo",eotnfZ:"EET",debian:nil,centos:nil,osx:"zoneinfo/Europe/Tallinn")
[:fugit, "1.10.1"]
[:now, 2024-03-25 17:31:15.191495 +0200, :zone, "EET"]

The text was updated successfully, but these errors were encountered:

jmettraux · 2024-03-25T23:54:19Z

Hello,

as a preliminary remark, a reminder that Time.parse(str) does not care about time zones:

# ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-openbsd7.4]

require 'time'


ENV['TZ'] = 'Europe/Tallinn'

p Time.now
  # 2024-03-26 01:19:30.188064864 +0200

p Time.parse("2012-10-28 02:59:00 EEST")
p Time.parse("2012-10-28 02:59:00 Europe/Tallinn")
  # 2012-10-28 02:59:00 +0300
  # 2012-10-28 02:59:00 +0300

p Time.parse("2012-10-28 02:59:00 Some/Where")
p Time.parse("2012-10-28 02:59:00 XXX")
  # 2012-10-28 02:59:00 +0300
  # 2012-10-28 02:59:00 +0300



ENV['TZ'] = 'Asia/Tokyo'

p Time.now
  # 2024-03-26 08:19:30.18919636 +0900

p Time.parse("2012-10-28 02:59:00 EEST")
p Time.parse("2012-10-28 02:59:00 Europe/Tallinn")
  # 2012-10-28 02:59:00 +0900
  # 2012-10-28 02:59:00 +0900

p Time.parse("2012-10-28 02:59:00 Some/Where")
p Time.parse("2012-10-28 02:59:00 XXX")
  # 2012-10-28 02:59:00 +0900
  # 2012-10-28 02:59:00 +0900

floraison/fugit#97

jmettraux · 2024-03-26T00:26:18Z

Tinkering:

# ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-openbsd7.4]

require 'fugit'

ENV['TZ'] = 'Europe/Tallinn'
  # approximating OP's situation...


p Fugit::Cron.parse("*/1 * * * *")
  .next_time(Time.parse("2012-10-28 02:59:00 EEST")).to_t
    # => 2012-10-28 03:00:00 +0300  ## because ENV TZ is Europe/Tallinn
p Fugit::Cron.parse("*/1 * * * *")
  .next_time(Fugit.parse("2012-10-28 02:59:00 EEST")).to_t
    # => 2012-10-28 10:00:00 +0200  ## off
p Fugit::Cron.parse("*/1 * * * *")
  .next_time(Fugit.parse("2012-10-28 02:59:00 Europe/Tallin")).to_t
    # => 2012-10-28 03:00:00 +0300 ## OK

##

#p Fugit::Cron.parse("*/1 * * * *")
#  .next_time(Time.parse("2012-10-28 02:59:00 EEST") + 1.minute)
#p Fugit::Cron.parse("*/1 * * * *")
#  .next_time(Time.parse("2012-10-28 02:59:00 EEST") + 60)
#p Fugit::Cron.parse("*/1 * * * *")
#  .next_time(Fugit.parse("2012-10-28 02:59:00 EEST") + 60).to_t
p Fugit::Cron.parse("*/1 * * * *")
  .next_time(Fugit.parse("2012-10-28 02:59:00 Europe/Tallin") + 60).to_t
    # => 2012-10-28 03:01:00 +0300
#/Users/traf/.rbenv/versions/3.2.3/lib/ruby/gems/3.2.0/gems/et-orbi-1.2.11/lib/et-orbi/time.rb:82
#   :in `initialize': Cannot determine timezone from "EEST" (ArgumentError)

##

#p Fugit::Cron.parse("*/1 * * * *")
#  .next_time(Time.parse("2012-10-28 03:00:00 EEST")).to_t
p Fugit::Cron.parse("*/1 * * * *")
  .next_time(Fugit.parse("2012-10-28 03:00:00 EEST")).to_t
    # => 2012-10-28 10:01:00 +0200
p Fugit::Cron.parse("*/1 * * * *")
  .next_time(Fugit.parse("2012-10-28 03:00:00 Europe/Tallinn")).to_t
    # => ~/.gem/ruby/3.2.2/gems/et-orbi-1.2.11/lib/et-orbi/make.rb:65
    #      :in `make_time': Cannot turn nil to a ::EtOrbi::EoTime instance
    #      (ArgumentError)
	#      from ~/w/fugit/lib/fugit/cron.rb:247:in `next_time'
p Fugit.parse("2012-10-28 03:00:00 Europe/Tallinn")
  # => nil
p EtOrbi.parse("2012-10-28 03:00:00 Europe/Tallinn")
  # => ~/.gem/ruby/3.2.2/gems/tzinfo-2.0.6/lib/tzinfo/timezone.rb:525:in `period_for_local':
  #         2012-10-28 03:00:00 is an ambiguous local time. (TZInfo::AmbiguousTime)
  # from ~/.gem/ruby/3.2.2/gems/tzinfo-2.0.6/lib/tzinfo/timezone.rb:652:in `block in local_to_utc'
  # from ~/.gem/ruby/3.2.2/gems/tzinfo-2.0.6/lib/tzinfo/timestamp.rb:144:in `for'
  # from ~/.gem/ruby/3.2.2/gems/tzinfo-2.0.6/lib/tzinfo/timezone.rb:648:in `local_to_utc'
  # from ~/.gem/ruby/3.2.2/gems/et-orbi-1.2.11/lib/et-orbi/make.rb:46:in `parse'
p (Fugit.parse("2012-10-28 02:59:00 Europe/Tallinn") + 60).to_t
  # => 2012-10-28 03:00:00 +0300

##

#p Fugit::Cron.parse("*/1 * * * *")
#  .next_time(Time.parse("2012-10-28 02:59:00 Europe/Tallinn") + 1.minute)
#p Fugit::Cron.parse("*/1 * * * *")
#  .next_time(Time.parse("2012-10-28 02:59:00 Europe/Tallinn") + 60)
p Fugit::Cron.parse("*/1 * * * *")
  .next_time(Fugit.parse("2012-10-28 02:59:00 Europe/Tallinn") + 60).to_t
    # => 2012-10-28 03:01:00 +0300

jmettraux · 2024-03-26T00:44:21Z

Further tinkering:

This works:

require 'fugit'

ENV['TZ'] = 'Europe/Tallinn'

#c = Fugit.parse_cron('*/1 * * * *') # equivalent to
c = Fugit.parse_cron('* * * * *')

t = Fugit.parse('2012-10-28 02:59:00 Europe/Tallinn')

70.times do |i|
  puts "%2d - %s" % [ i, t ? t.to_t.inspect : 'nil' ]
  t = c.next_time(t)
end

It transitions smoothly:

...
58 - 2012-10-28 03:57:00 +0300
59 - 2012-10-28 03:58:00 +0300
60 - 2012-10-28 03:59:00 +0300
61 - 2012-10-28 03:00:00 +0200
62 - 2012-10-28 03:01:00 +0200
63 - 2012-10-28 03:02:00 +0200
...

But making it start at '2012-10-28 03:00:00 Europe/Tallinn' instead of '2012-10-28 02:59:00 Europe/Tallinn' has nil for t and it fails immediately. Fugit.parse('2023-10-28 03:00:00') (in Europe/Tallinn) also returns nil.

I need to find a way in fugit or et-orbi to return the right time when parsing an ambiguous timezone.

I will go on investigating tonight after work. Thanks for reporting that.

trafium · 2024-03-26T08:11:07Z

Thanks @jmettraux, I was unaware of that weird behaviour of Time.parse with time zones. Still trying to grasp what is going on exactly though.

But keeping that in mind, I found out that I can use Time.find_zone!("Europe/Tallinn").parse("2012-10-28 02:59:00") which gives me ActiveSupport::TimeWithZone and it does not break in Fugit that way.

Time.find_zone!("Europe/Tallinn").parse("2012-10-28 02:59:00") + 1.minute
#=> Sun, 28 Oct 2012 03:00:00.000000000 EEST +03:00
(Time.find_zone!("Europe/Tallinn").parse("2012-10-28 02:59:00") + 1.minute).zone
#=> "EEST"
(Time.find_zone!("Europe/Tallinn").parse("2012-10-28 02:59:00") + 1.minute).dst?
#=> true
(Time.find_zone!("Europe/Tallinn").parse("2012-10-28 02:59:00") + 1.minute) == (Time.parse("2012-10-28 02:59:00 Europe/Tallinn") + 1.minute)
#=> true
(Time.find_zone!("Europe/Tallinn").parse("2012-10-28 02:59:00") + 1.minute).zone == (Time.parse("2012-10-28 02:59:00 Europe/Tallinn") + 1.minute).zone
#=> true
(Time.find_zone!("Europe/Tallinn").parse("2012-10-28 02:59:00") + 1.minute).dst? == (Time.parse("2012-10-28 02:59:00 Europe/Tallinn") + 1.minute).dst?
#=> true
Fugit::Cron.parse("*/1 * * * *").next_time(Time.find_zone!("Europe/Tallinn").parse("2012-10-28 02:59:00") + 1.minute).to_t
#=> 2012-10-28 03:01:00 +0300
Fugit::Cron.parse("*/1 * * * *").next_time(Time.find_zone!("Europe/Tallinn").parse("2012-10-28 03:59:00")).to_s
#=> "2012-10-28 03:00:00 +0200"

jmettraux self-assigned this Mar 25, 2024

jmettraux added a commit to floraison/et-orbi that referenced this issue Mar 26, 2024

Simplify ambiguous tz spec

c994a51

floraison/fugit#97

jmettraux mentioned this issue Apr 2, 2024

Cron inconsistent behaviour with union vs intersection #98

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#next_time breaks on DST end #97

#next_time breaks on DST end #97

trafium commented Mar 25, 2024 •

edited

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jmettraux commented Mar 25, 2024

jmettraux commented Mar 26, 2024

jmettraux commented Mar 26, 2024

trafium commented Mar 26, 2024

#next_time breaks on DST end #97

#next_time breaks on DST end #97

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trafium commented Mar 25, 2024 • edited Loading

Issue description

How to reproduce

Error and error backtrace (if any)

Expected behaviour

Context

jmettraux commented Mar 25, 2024

jmettraux commented Mar 26, 2024

jmettraux commented Mar 26, 2024

trafium commented Mar 26, 2024

trafium commented Mar 25, 2024 •

edited

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