Bug #20674: Time zone conversion issue Time.at

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 3.2.2
• Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

[moustafasallam (Moustafa Sallam Mahmoud)]

Time.at converts the epoch time to the local time zone But there seems a weird case with Central Time (US & Canada)
where it convert it one hour earlier for example
take this timestamp 1728018000 when converted it to Central Time (US & Canada) with Time.at

=> Time.zone = "Central Time (US & Canada)"
=> "Central Time (US & Canada)"
=> Time.at(1728018000)
=> 2024-10-04 01:00:00 -0400

While using ActiveSupport::TimeZone

ActiveSupport::TimeZone['Central Time (US & Canada)'].at(1728018000)
=> Fri, 04 Oct 2024 00:00:00.000000000 CDT -05:00

so Time.at convert it to -4 while ActiveSupport::TimeZone convert it to -5

[moustafasallam (Moustafa Sallam Mahmoud)]

• ruby -v set to ruby 3.2.2

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)
• Status changed from Open to Rejected

Time.zone= method is not defined in Ruby itself, probably defined by ActiveSupport, I don't know from where it comes.

So Time.at is not affected by it at all, and -4 would have come from your "TZ" environment variable or system configuration.

[nobu (Nobuyoshi Nakada)]

• Status changed from Rejected to Third Party's Issue

require 'active_support'
require 'active_support/core_ext'

Time.zone = "Central Time (US & Canada)"
p Time.at(1728018000, in: Time.zone) #=> 2024-10-04 00:00:00 -0500

[nobu (Nobuyoshi Nakada)]

• Status changed from Third Party's Issue to Rejected