Forum: Ruby-core DateTime.strptime() doesn't work correctly for '%s %z'

B11f10c4cd9d53970e7be20caa43f940?d=identicon&s=25 unknown (Guest)
on 2014-05-04 12:12
(Received via mailing list)
Issue #9794 has been updated by Akira Tanaka.

tadayoshi funaba wrote:
> Akira Tanaka wrote:
> > tadayoshi funaba wrote:
> > もしかして、DateTime.strptime に与えるフォーマットに時刻 (時間軸上の点) を同定するのに関係しない要素は与えるべきでない、
> > と感じるという話でしょうか。
> 極端な話、単に読み飛ばすだけでも意味があると思ってます。


ここで興味の対象は "%s %z" がなぜいけないのか、という点です。

私の思ったのは、もし、ふなばさんが DateTime.strptime に与えるフォーマットに時刻 (時間軸上の点) を
フォーマットに "%s %z" を与えるのは %z がまさに関係しない要素なので、



Bug #9794: DateTime.strptime() doesn't work correctly for '%s %z'

* Author: Felipe Contreras
* Status: Rejected
* Priority: Low
* Assignee: tadayoshi funaba
* Category: ext
* Target version:
* ruby -v: 2.1.1p76
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
Time.strptime() works correctly:

    Time.strptime('0 +0100', '%s %z').strftime('%s %z')
    => "0 +0100"

But DateTime.strptime() doesn't:

    DateTime.strptime('0 +0100', '%s %z').strftime('%s %z')
    => "0 +0000"

In Rubinious it does work correctly:

    DateTime.strptime('0 +0100', '%s %z').strftime('%s %z')
    => "0 +0100"

This make the RubySL date space fail:

    DateTime#strptime parses seconds and timezone correctly FAILED
    Expected "1970-01-01T00:00:00+00:00"
     to equal "1970-01-01T01:00:00+01:00"

In addition, both C and perl preserver the offset correctly when doing
'%s %z'.

So it's very clear DateTime.strptime() has to be fixed.

Patch attached.

0001-datetime-fix-strptime-s-z.patch (1.94 KB)
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