REGR: Regression in DatetimeIndex iteration with a Fixed/Local offset timezone (GH8890)

doc/source/whatsnew/v0.15.2.txt

@@ -118,6 +118,7 @@ Bug Fixes
      s.loc['c':'a':-1]
 
 - Report a ``TypeError`` when invalid/no paramaters are passed in a groupby (:issue:`8015`)
+- Regression in DatetimeIndex iteration with a Fixed/Local offset timezone (:issue:`8890`)
 - Bug in packaging pandas with ``py2app/cx_Freeze`` (:issue:`8602`, :issue:`8831`)
 - Bug in ``groupby`` signatures that didn't include \*args or \*\*kwargs (:issue:`8733`).
 - ``io.data.Options`` now raises ``RemoteDataError`` when no expiry dates are available from Yahoo and when it receives no data from Yahoo (:issue:`8761`), (:issue:`8783`).

pandas/tseries/tests/test_timeseries.py

@@ -2313,6 +2313,27 @@ def test_map(self):
         exp = [f(x) for x in rng]
         self.assert_numpy_array_equal(result, exp)
 
+
+    def test_iteration_preserves_tz(self):
+
+        tm._skip_if_no_dateutil()
+
+        # GH 8890
+        import dateutil
+        index = date_range("2012-01-01", periods=3, freq='H', tz='US/Eastern')
+
+        for i, ts in enumerate(index):
+            result = ts
+            expected = index[i]
+            self.assertEqual(result, expected)
+
+        index = date_range("2012-01-01", periods=3, freq='H', tz=dateutil.tz.tzoffset(None, -28800))
+
+        for i, ts in enumerate(index):
+            result = ts
+            expected = index[i]
+            self.assertEqual(result, expected)
+
     def test_misc_coverage(self):
         rng = date_range('1/1/2000', periods=5)
         result = rng.groupby(rng.day)

pandas/tslib.pyx

@@ -122,7 +122,9 @@ def ints_to_pydatetime(ndarray[int64_t] arr, tz=None, offset=None, box=False):
                 else:
                     pandas_datetime_to_datetimestruct(value, PANDAS_FR_ns, &dts)
                     dt = func_create(value, dts, tz, offset)
-                    result[i] = dt + tz.utcoffset(dt)
+                    if not box:
+                        dt = dt + tz.utcoffset(dt)
+                    result[i] = dt
         else:
             trans = _get_transitions(tz)
             deltas = _get_deltas(tz)