[Python-Dev] TZ-aware local time (original) (raw)

Alexander Belopolsky alexander.belopolsky at gmail.com
Wed Jun 6 00:33:28 CEST 2012

On Tue, Jun 5, 2012 at 6:07 PM, Guido van Rossum <guido at python.org> wrote:

I've also been arguing against "local time" tzinfo Why? I don't see your argumentation against such a tzinfo in the bug

See http://bugs.python.org/issue9063 .

The problem is again the DST ambiguity. One day a year, datetime(y, m, d, 1, 30, tzinfo=Local) represents two different times and another day it represents no valid time. Many applications can ignore this problem but stdlib should not.

The documentation example (fixed in issue 9063) addresses the ambiguity by defaulting to standard time, but it does this at a cost of having no way to spell "the other hour."

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