Bug #12259: DateTime.parse does not take into account the system timezone

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin13]
• Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN

[sonots (Naotoshi Seo)]

DateTime.parse does not take into account the system timezone although Time.parse does take into account the system timezone.

irb(main):002:0> DateTime.parse('2011-10-10 10:00:00')
=> #<DateTime: 2011-10-10T10:00:00+00:00 ((2455845j,36000s,0n),+0s,2299161j)>
irb(main):005:0> Time.parse('2011-10-10 10:00:00')
=> 2011-10-10 10:00:00 +0900

Are there any reasons that DateTime.parse behaves like this?
Can this behavior be changed, or do we have to keep this behavior for lower version compatibility?

[sonots (Naotoshi Seo)]

• Subject changed from DateTime.parse does not take into account system time to DateTime.parse does not take into account the system timezone

[jeremyevans0 (Jeremy Evans)]

I do not think this is a bug. DateTime has always defaulted to UTC, not just in DateTime.parse:

DateTime.new.zone
# => "+00:00"

DateTime.strptime('2009', '%Y').zone
# => "+00:00"

DateTime.jd(2458000)
# => "+00:00"

To switch to defaulting to local time for compatibility with Time would be a huge break to backwards compatibility, and I don't think such a change is worthwhile. I think DateTime mostly exists for backwards compatibility, since starting in Ruby 2.6, Time can handle timezones (timezone handling was the last major advantage of DateTime over Time).

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Rejected