BUG: Some offsets.apply cannot handle tz properly

doc/source/v0.14.1.txt

@@ -224,6 +224,8 @@ Bug Fixes
 
 
 
+- Bug in passing input with ``tzinfo`` to some offsets ``apply``, ``rollforward`` or ``rollback`` resets ``tzinfo`` or raises ``ValueError`` (:issue:`7465`)
+
 
 - BUG in ``resample`` raises ``ValueError`` when target contains ``NaT`` (:issue:`7227`)
 

pandas/tseries/offsets.py

@@ -48,13 +48,20 @@ def wrapper(self, other):
         elif isinstance(other, np.datetime64):
             other = as_timestamp(other)
 
+        tz = getattr(other, 'tzinfo', None)
         result = func(self, other)
 
         if self.normalize:
             result = tslib.normalize_date(result)
 
         if isinstance(other, Timestamp) and not isinstance(result, Timestamp):
             result = as_timestamp(result)
+
+        if tz is not None:
+            if isinstance(result, Timestamp) and result.tzinfo is None:
+                result = result.tz_localize(tz)
+            elif isinstance(result, datetime) and result.tzinfo is None:
+                result = tz.localize(result)
         return result
     return wrapper
 
@@ -570,6 +577,11 @@ def _to_dt64(dt, dtype='datetime64'):
         # > np.datetime64(dt.datetime(2013,5,1),dtype='datetime64[D]')
         # numpy.datetime64('2013-05-01T02:00:00.000000+0200')
         # Thus astype is needed to cast datetime to datetime64[D]
+
+        if getattr(dt, 'tzinfo', None) is not None:
+            i8 = tslib.pydt_to_i8(dt)
+            dt = tslib.tz_convert_single(i8, 'UTC', dt.tzinfo)
+            dt = Timestamp(dt)
         dt = np.datetime64(dt)
         if dt.dtype.name != dtype:
             dt = dt.astype(dtype)
@@ -966,13 +978,18 @@ def apply(self, other):
                 months = self.n + 1
 
         other = self.getOffsetOfMonth(as_datetime(other) + relativedelta(months=months, day=1))
-        other = datetime(other.year, other.month, other.day,
-                         base.hour, base.minute, base.second, base.microsecond)
+        other = datetime(other.year, other.month, other.day, base.hour,
+                         base.minute, base.second, base.microsecond)
+        if getattr(other, 'tzinfo', None) is not None:
+            other = other.tzinfo.localize(other)
         return other
 
     def getOffsetOfMonth(self, dt):
         w = Week(weekday=self.weekday)
+
         d = datetime(dt.year, dt.month, 1)
+        if getattr(dt, 'tzinfo', None) is not None:
+            d = dt.tzinfo.localize(d)
 
         d = w.rollforward(d)
 
@@ -985,6 +1002,8 @@ def onOffset(self, dt):
         if self.normalize and not _is_normalized(dt):
             return False
         d = datetime(dt.year, dt.month, dt.day)
+        if getattr(dt, 'tzinfo', None) is not None:
+            d = dt.tzinfo.localize(d)
         return d == self.getOffsetOfMonth(dt)
 
     @property
@@ -1056,6 +1075,8 @@ def apply(self, other):
     def getOffsetOfMonth(self, dt):
         m =  MonthEnd()
         d = datetime(dt.year, dt.month, 1, dt.hour, dt.minute, dt.second, dt.microsecond)
+        if getattr(dt, 'tzinfo', None) is not None:
+            d = dt.tzinfo.localize(d)
 
         eom = m.rollforward(d)
 
@@ -1134,6 +1155,10 @@ class BQuarterEnd(QuarterOffset):
     @apply_wraps
     def apply(self, other):
         n = self.n
+        base = other
+        other = datetime(other.year, other.month, other.day,
+                         other.hour, other.minute, other.second,
+                         other.microsecond)
 
         wkday, days_in_month = tslib.monthrange(other.year, other.month)
         lastBDay = days_in_month - max(((wkday + days_in_month - 1)
@@ -1149,7 +1174,8 @@ def apply(self, other):
             n = n + 1
 
         other = as_datetime(other) + relativedelta(months=monthsToGo + 3 * n, day=31)
-
+        if getattr(base, 'tzinfo', None) is not None:
+            other = base.tzinfo.localize(other)
         if other.weekday() > 4:
             other = other - BDay()
 
@@ -1216,6 +1242,8 @@ def apply(self, other):
         result = datetime(other.year, other.month, first,
                           other.hour, other.minute, other.second,
                           other.microsecond)
+        if getattr(other, 'tzinfo', None) is not None:
+            result = other.tzinfo.localize(result)
         return as_timestamp(result)
 
 
@@ -1242,6 +1270,10 @@ def isAnchored(self):
     @apply_wraps
     def apply(self, other):
         n = self.n
+        base = other
+        other = datetime(other.year, other.month, other.day,
+                         other.hour, other.minute, other.second,
+                         other.microsecond)
         other = as_datetime(other)
 
         wkday, days_in_month = tslib.monthrange(other.year, other.month)
@@ -1254,7 +1286,8 @@ def apply(self, other):
             n = n - 1
 
         other = other + relativedelta(months=monthsToGo + 3 * n, day=31)
-
+        if getattr(base, 'tzinfo', None) is not None:
+            other = base.tzinfo.localize(other)
         return as_timestamp(other)
 
     def onOffset(self, dt):
@@ -1589,6 +1622,10 @@ def apply(self, other):
                         datetime(other.year, self.startingMonth, 1))
         next_year = self.get_year_end(
                         datetime(other.year + 1, self.startingMonth, 1))
+        if getattr(other, 'tzinfo', None) is not None:
+            prev_year = other.tzinfo.localize(prev_year)
+            cur_year = other.tzinfo.localize(cur_year)
+            next_year = other.tzinfo.localize(next_year)
 
         if n > 0:
             if other == prev_year:
@@ -1647,7 +1684,9 @@ def get_year_end(self, dt):
             return self._get_year_end_last(dt)
 
     def get_target_month_end(self, dt):
-        target_month = datetime(year=dt.year, month=self.startingMonth, day=1)
+        target_month = datetime(dt.year, self.startingMonth, 1)
+        if getattr(dt, 'tzinfo', None) is not None:
+            target_month = dt.tzinfo.localize(target_month)
         next_month_first_of = target_month + relativedelta(months=+1)
         return next_month_first_of + relativedelta(days=-1)
 
@@ -1665,7 +1704,9 @@ def _get_year_end_nearest(self, dt):
                 return backward
 
     def _get_year_end_last(self, dt):
-        current_year = datetime(year=dt.year, month=self.startingMonth, day=1)
+        current_year = datetime(dt.year, self.startingMonth, 1)
+        if getattr(dt, 'tzinfo', None) is not None:
+            current_year = dt.tzinfo.localize(current_year)
         return current_year + self._offset_lwom
 
     @property
@@ -1878,13 +1919,14 @@ class Easter(DateOffset):
     '''
     def __init__(self, n=1, **kwds):
         super(Easter, self).__init__(n, **kwds)
-        
+
     @apply_wraps
     def apply(self, other):
-
         currentEaster = easter(other.year)
         currentEaster = datetime(currentEaster.year, currentEaster.month, currentEaster.day)
-
+        if getattr(other, 'tzinfo', None) is not None:
+            currentEaster = other.tzinfo.localize(currentEaster)
+
         # NOTE: easter returns a datetime.date so we have to convert to type of other
         if self.n >= 0:
             if other >= currentEaster:
@@ -1905,6 +1947,7 @@ def onOffset(self, dt):
         if self.normalize and not _is_normalized(dt):
             return False
         return date(dt.year, dt.month, dt.day) == easter(dt.year)
+
 #----------------------------------------------------------------------
 # Ticks
 

pandas/tseries/tests/test_offsets.py

@@ -185,6 +185,8 @@ def setUp(self):
                           'Milli': Timestamp('2011-01-01 09:00:00.001000'),
                           'Micro': Timestamp('2011-01-01 09:00:00.000001'),
                           'Nano': Timestamp(np.datetime64('2011-01-01T09:00:00.000000001Z'))}
+
+        self.timezones = ['UTC', 'Asia/Tokyo', 'US/Eastern']
 
     def test_return_type(self):
         for offset in self.offset_types:
@@ -214,6 +216,24 @@ def _check_offsetfunc_works(self, offset, funcname, dt, expected,
         self.assert_(isinstance(result, Timestamp))
         self.assertEqual(result, expected)
 
+        if isinstance(dt, np.datetime64):
+            # test tz when input is datetime or Timestamp
+            return
+
+        tm._skip_if_no_pytz()
+        import pytz
+        for tz in self.timezones:
+            expected_localize = expected.tz_localize(tz)
+
+            dt_tz = pytz.timezone(tz).localize(dt)
+            result = func(dt_tz)
+            self.assert_(isinstance(result, datetime))
+            self.assertEqual(result, expected_localize)
+
+            result = func(Timestamp(dt, tz=tz))
+            self.assert_(isinstance(result, datetime))
+            self.assertEqual(result, expected_localize)
+
     def _check_nanofunc_works(self, offset, funcname, dt, expected):
         offset = self._get_offset(offset)
         func = getattr(offset, funcname)
@@ -334,9 +354,7 @@ def test_rollback(self):
                                                  dt, expected, normalize=True)
 
     def test_onOffset(self):
-
         for offset in self.offset_types:
-
             dt = self.expecteds[offset.__name__]
             offset_s = self._get_offset(offset)
             self.assert_(offset_s.onOffset(dt))

pandas/tseries/tests/test_timeseries.py

@@ -309,13 +309,6 @@ def test_recreate_from_data(self):
             idx = DatetimeIndex(org, freq=f)
             self.assertTrue(idx.equals(org))
 
-        # unbale to create tz-aware 'A' and 'C' freq
-        if _np_version_under1p7:
-            freqs = ['M', 'Q', 'D', 'B', 'T', 'S', 'L', 'U', 'H']
-        else:
-            freqs = ['M', 'Q', 'D', 'B', 'T', 'S', 'L', 'U', 'H', 'N']
-
-        for f in freqs:
             org = DatetimeIndex(start='2001/02/01 09:00', freq=f, tz='US/Pacific', periods=1)
             idx = DatetimeIndex(org, freq=f, tz='US/Pacific')
             self.assertTrue(idx.equals(org))

pandas/util/testing.py

@@ -209,6 +209,12 @@ def setUpClass(cls):
     cls.setUpClass = setUpClass
     return cls
 
+def _skip_if_no_pytz():
+    try:
+        import pytz
+    except ImportError:
+        import nose
+        raise nose.SkipTest("pytz not installed")
 
 #------------------------------------------------------------------------------
 # locale utilities