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Re: Help needed for pandas bug: Could anybody verify the suspicion that tzdata might have some influence?

At second thought it might not be a bug in python-tz, but some
undefined behavior that results from the pandas use of tz._utcoffset: 

>   tz = pytz.timezone('Asia/Tokyo')
>   dt = datetime.datetime(2011,1,1)
>   In[76]:  tz.utcoffset(dt)
>   Out[76]: datetime.timedelta(0, 32400)
>   In [77]: tz._utcoffset
>   Out[77]: datetime.timedelta(0, 33540)

In the first case tz.utcoffset has a reference date, and can select the
 proper time offset, i.e. in 2011 this is 09:00, but tz._utcoffset
doesn't know which year it refers to, and hence, it picks one offset,
in this case the first on the list that has the additional 19 minutes

I do also not understand why the test fails only now though, and why
pandas picks one code path to define the test case, and another to
create the expected value.


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