Fixes timezone drop when encoding it in msgpack

doc/source/whatsnew/v0.24.2.rst

@@ -52,6 +52,7 @@ Bug Fixes
 **I/O**
 
 - Bug in reading a HDF5 table-format ``DataFrame`` created in Python 2, in Python 3 (:issue:`24925`)
+- Bug in retaining timezone in :meth:`read_msgpack` when saving and loading the :class"`DataFrame` from ``msgpack``. (:issue:`25148`)
 - Bug in reading a JSON with ``orient='table'`` generated by :meth:`DataFrame.to_json` with ``index=False`` (:issue:`25170`)
 - Bug where float indexes could have misaligned values when printing (:issue:`25061`)
 -

pandas/io/packers.py

@@ -43,8 +43,10 @@
 from textwrap import dedent
 import warnings
 
+import dateutil
 from dateutil.parser import parse
 import numpy as np
+from pytz import FixedOffset, _FixedOffset
 
 import pandas.compat as compat
 from pandas.compat import u, u_safe
@@ -387,10 +389,19 @@ def encode(obj):
                     u'compress': compressor}
         elif isinstance(obj, DatetimeIndex):
             tz = getattr(obj, 'tz', None)
-
+            tztype = None
             # store tz info and data as UTC
             if tz is not None:
-                tz = u(tz.zone)
+                if isinstance(tz, _FixedOffset):
+                    tz, tztype = u(str(tz._minutes)), u('fixedoffset')
+                elif isinstance(tz, dateutil.tz.tzutc):
+                    tz, tztype = u('UTC'), u('tzutc')
+                elif isinstance(tz, dateutil.tz.tzfile):
+                    tz, tztype = u(tz._filename), u('tzfile')
+                elif isinstance(tz, dateutil.tz.tzlocal):
+                    tz, tztype = u('local'), u('tzlocal')
+                else:
+                    tz, tztype = u(tz.zone), u('zone')
                 obj = obj.tz_convert('UTC')
             return {u'typ': u'datetime_index',
                     u'klass': u(obj.__class__.__name__),
@@ -399,6 +410,7 @@ def encode(obj):
                     u'data': convert(obj.asi8),
                     u'freq': u_safe(getattr(obj, 'freqstr', None)),
                     u'tz': tz,
+                    u'tztype': tztype,
                     u'compress': compressor}
         elif isinstance(obj, (IntervalIndex, IntervalArray)):
             if isinstance(obj, IntervalIndex):
@@ -609,7 +621,15 @@ def decode(obj):
         d = dict(name=obj[u'name'], freq=obj[u'freq'])
         result = DatetimeIndex(data, **d)
         tz = obj[u'tz']
-
+        tztype = obj['tztype'] if 'tztype' in obj.keys() else None
+        if tztype == u'fixedoffset':
+            tz = FixedOffset(int(tz))
+        elif tztype == u'tzfile':
+            tz = dateutil.tz.gettz(tz)
+        elif tztype == u'tzlocal':
+            tz = dateutil.tz.tzlocal()
+        elif tztype == u'tzutc':
+            tz = dateutil.tz.tzutc()
         # reverse tz conversion
         if tz is not None:
             result = result.tz_localize('UTC').tz_convert(tz)

pandas/tests/io/test_packers.py

@@ -393,6 +393,13 @@ def categorical_index(self):
         result = self.encode_decode(df)
         tm.assert_frame_equal(result, df)
 
+    def test_timezone_encode_decode(self, tz_aware_fixture):
+        tz = tz_aware_fixture
+        expected = date_range(start='2018-12-02 14:50:00',
+                              end='2018-12-03 03:11:00', freq='1min', tz=tz)
+        result = self.encode_decode(expected)
+        tm.assert_index_equal(result, expected)
+
 
 class TestSeries(TestPackers):