Re: [Datetime-SIG] Equality of tzinfo objects

On Thu, Nov 3, 2016, at 14:24, Alexander Belopolsky wrote:
On Thu, Nov 3, 2016 at 2:09 PM, Paul G <paul@ganssle.io> wrote:
I don't understand why it must be the case that something is considered an "inter-zone" comparison whenever `t.tzinfo is not s.tzinfo`. What is the objection to using `t.tzinfo != s.tzinfo` as the criterion? In general these will be equivalent, but using __eq__ allows time zone providers to determine what is considered an "inter-zone" comparison.
This was probably the case of premature optimization. I cannot think of any valid reason, but datetime comparisons have always compared tzinfos using "is" rather than "==" operator. We can probably still make a change, but it should be implemented and thoroughly tested first. Please open a bug report.
I don't think this really goes far enough. Sure, it allows for times in America/New_York and US/Eastern to be compared, but doesn't allow for times from America/Indiana/Indianapolis - which should be considered the same time zone after 2007, and mechanisms should be provided for a sufficiently sophisticated pytz implementation to determine this - to be compared. So if I understand correctly the purpose of comparing the timezones at all is for ambiguous times, i.e. those near the DST fall-back transition - and other interzone comparisons are allowed? Wasn't resolving this supposed to be the purpose of the fold bit - how do ambiguous times still exist at all?
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