bpo-22005: Fixed unpickling instances of datetime classes pickled by Python 2. (GH-11017)

encoding='latin1' should be used for successful decoding.

5 files changed, 333 insertions, 95 deletions

diff --git a/Doc/library/pickle.rst b/Doc/library/pickle.rst
index 4f9d3596b6..5fe49a013b 100644
--- a/Doc/library/pickle.rst
+++ b/Doc/library/pickle.rst
@@ -243,6 +243,9 @@ process more convenient:
    *errors* tell pickle how to decode 8-bit string instances pickled by Python
    2; these default to 'ASCII' and 'strict', respectively.  The *encoding* can
    be 'bytes' to read these 8-bit string instances as bytes objects.
+   Using ``encoding='latin1'`` is required for unpickling NumPy arrays and
+   instances of :class:`~datetime.datetime`, :class:`~datetime.date` and
+   :class:`~datetime.time` pickled by Python 2.
 
 .. function:: loads(bytes_object, \*, fix_imports=True, encoding="ASCII", errors="strict")
 
@@ -260,6 +263,9 @@ process more convenient:
    *errors* tell pickle how to decode 8-bit string instances pickled by Python
    2; these default to 'ASCII' and 'strict', respectively.  The *encoding* can
    be 'bytes' to read these 8-bit string instances as bytes objects.
+   Using ``encoding='latin1'`` is required for unpickling NumPy arrays and
+   instances of :class:`~datetime.datetime`, :class:`~datetime.date` and
+   :class:`~datetime.time` pickled by Python 2.
 
 
 The :mod:`pickle` module defines three exceptions:
diff --git a/Lib/datetime.py b/Lib/datetime.py
index 292919fd79..4780b6df8f 100644
--- a/Lib/datetime.py
+++ b/Lib/datetime.py
@@ -808,9 +808,19 @@ class date:
 
         year, month, day (required, base 1)
         """
-        if month is None and isinstance(year, bytes) and len(year) == 4 and \
-                1 <= year[2] <= 12:
+        if (month is None and
+            isinstance(year, (bytes, str)) and len(year) == 4 and
+            1 <= ord(year[2:3]) <= 12):
             # Pickle support
+            if isinstance(year, str):
+                try:
+                    year = year.encode('latin1')
+                except UnicodeEncodeError:
+                    # More informative error message.
+                    raise ValueError(
+                        "Failed to encode latin1 string when unpickling "
+                        "a date object. "
+                        "pickle.load(data, encoding='latin1') is assumed.")
             self = object.__new__(cls)
             self.__setstate(year)
             self._hashcode = -1
@@ -1184,8 +1194,18 @@ class time:
         tzinfo (default to None)
         fold (keyword only, default to zero)
         """
-        if isinstance(hour, bytes) and len(hour) == 6 and hour[0]&0x7F < 24:
+        if (isinstance(hour, (bytes, str)) and len(hour) == 6 and
+            ord(hour[0:1])&0x7F < 24):
             # Pickle support
+            if isinstance(hour, str):
+                try:
+                    hour = hour.encode('latin1')
+                except UnicodeEncodeError:
+                    # More informative error message.
+                    raise ValueError(
+                        "Failed to encode latin1 string when unpickling "
+                        "a time object. "
+                        "pickle.load(data, encoding='latin1') is assumed.")
             self = object.__new__(cls)
             self.__setstate(hour, minute or None)
             self._hashcode = -1
@@ -1496,8 +1516,18 @@ class datetime(date):
 
     def __new__(cls, year, month=None, day=None, hour=0, minute=0, second=0,
                 microsecond=0, tzinfo=None, *, fold=0):
-        if isinstance(year, bytes) and len(year) == 10 and 1 <= year[2]&0x7F <= 12:
+        if (isinstance(year, (bytes, str)) and len(year) == 10 and
+            1 <= ord(year[2:3])&0x7F <= 12):
             # Pickle support
+            if isinstance(year, str):
+                try:
+                    year = bytes(year, 'latin1')
+                except UnicodeEncodeError:
+                    # More informative error message.
+                    raise ValueError(
+                        "Failed to encode latin1 string when unpickling "
+                        "a datetime object. "
+                        "pickle.load(data, encoding='latin1') is assumed.")
             self = object.__new__(cls)
             self.__setstate(year, month)
             self._hashcode = -1
diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
index 78b123f5b1..2f838c4455 100644
--- a/Lib/test/datetimetester.py
+++ b/Lib/test/datetimetester.py
@@ -38,6 +38,7 @@ import _testcapi
 import _strptime
 #
 
+pickle_loads = {pickle.loads, pickle._loads}
 
 pickle_choices = [(pickle, pickle, proto)
                   for proto in range(pickle.HIGHEST_PROTOCOL + 1)]
@@ -1434,6 +1435,19 @@ class TestDate(HarmlessMixedComparison, unittest.TestCase):
             self.assertEqual(orig, derived)
         self.assertEqual(orig.__reduce__(), orig.__reduce_ex__(2))
 
+    def test_compat_unpickle(self):
+        tests = [
+            b"cdatetime\ndate\n(S'\\x07\\xdf\\x0b\\x1b'\ntR.",
+            b'cdatetime\ndate\n(U\x04\x07\xdf\x0b\x1btR.',
+            b'\x80\x02cdatetime\ndate\nU\x04\x07\xdf\x0b\x1b\x85R.',
+        ]
+        args = 2015, 11, 27
+        expected = self.theclass(*args)
+        for data in tests:
+            for loads in pickle_loads:
+                derived = loads(data, encoding='latin1')
+                self.assertEqual(derived, expected)
+
     def test_compare(self):
         t1 = self.theclass(2, 3, 4)
         t2 = self.theclass(2, 3, 4)
@@ -2098,6 +2112,24 @@ class TestDateTime(TestDate):
             derived = unpickler.loads(green)
             self.assertEqual(orig, derived)
 
+    def test_compat_unpickle(self):
+        tests = [
+            b'cdatetime\ndatetime\n('
+            b"S'\\x07\\xdf\\x0b\\x1b\\x14;\\x01\\x00\\x10\\x00'\ntR.",
+
+            b'cdatetime\ndatetime\n('
+            b'U\n\x07\xdf\x0b\x1b\x14;\x01\x00\x10\x00tR.',
+
+            b'\x80\x02cdatetime\ndatetime\n'
+            b'U\n\x07\xdf\x0b\x1b\x14;\x01\x00\x10\x00\x85R.',
+        ]
+        args = 2015, 11, 27, 20, 59, 1, 64**2
+        expected = self.theclass(*args)
+        for data in tests:
+            for loads in pickle_loads:
+                derived = loads(data, encoding='latin1')
+                self.assertEqual(derived, expected)
+
     def test_more_compare(self):
         # The test_compare() inherited from TestDate covers the error cases.
         # We just want to test lexicographic ordering on the members datetime
@@ -3069,6 +3101,19 @@ class TestTime(HarmlessMixedComparison, unittest.TestCase):
             derived = unpickler.loads(green)
             self.assertEqual(orig, derived)
 
+    def test_compat_unpickle(self):
+        tests = [
+            b"cdatetime\ntime\n(S'\\x14;\\x10\\x00\\x10\\x00'\ntR.",
+            b'cdatetime\ntime\n(U\x06\x14;\x10\x00\x10\x00tR.',
+            b'\x80\x02cdatetime\ntime\nU\x06\x14;\x10\x00\x10\x00\x85R.',
+        ]
+        args = 20, 59, 16, 64**2
+        expected = self.theclass(*args)
+        for data in tests:
+            for loads in pickle_loads:
+                derived = loads(data, encoding='latin1')
+                self.assertEqual(derived, expected)
+
     def test_bool(self):
         # time is always True.
         cls = self.theclass
@@ -3441,6 +3486,40 @@ class TestTimeTZ(TestTime, TZInfoBase, unittest.TestCase):
             self.assertEqual(derived.tzname(), 'cookie')
         self.assertEqual(orig.__reduce__(), orig.__reduce_ex__(2))
 
+    def test_compat_unpickle(self):
+        tests = [
+            b"cdatetime\ntime\n(S'\\x05\\x06\\x07\\x01\\xe2@'\n"
+            b"ctest.datetimetester\nPicklableFixedOffset\n(tR"
+            b"(dS'_FixedOffset__offset'\ncdatetime\ntimedelta\n"
+            b"(I-1\nI68400\nI0\ntRs"
+            b"S'_FixedOffset__dstoffset'\nNs"
+            b"S'_FixedOffset__name'\nS'cookie'\nsbtR.",
+
+            b'cdatetime\ntime\n(U\x06\x05\x06\x07\x01\xe2@'
+            b'ctest.datetimetester\nPicklableFixedOffset\n)R'
+            b'}(U\x14_FixedOffset__offsetcdatetime\ntimedelta\n'
+            b'(J\xff\xff\xff\xffJ0\x0b\x01\x00K\x00tR'
+            b'U\x17_FixedOffset__dstoffsetN'
+            b'U\x12_FixedOffset__nameU\x06cookieubtR.',
+
+            b'\x80\x02cdatetime\ntime\nU\x06\x05\x06\x07\x01\xe2@'
+            b'ctest.datetimetester\nPicklableFixedOffset\n)R'
+            b'}(U\x14_FixedOffset__offsetcdatetime\ntimedelta\n'
+            b'J\xff\xff\xff\xffJ0\x0b\x01\x00K\x00\x87R'
+            b'U\x17_FixedOffset__dstoffsetN'
+            b'U\x12_FixedOffset__nameU\x06cookieub\x86R.',
+        ]
+
+        tinfo = PicklableFixedOffset(-300, 'cookie')
+        expected = self.theclass(5, 6, 7, 123456, tzinfo=tinfo)
+        for data in tests:
+            for loads in pickle_loads:
+                derived = loads(data, encoding='latin1')
+                self.assertEqual(derived, expected, repr(data))
+                self.assertIsInstance(derived.tzinfo, PicklableFixedOffset)
+                self.assertEqual(derived.utcoffset(), timedelta(minutes=-300))
+                self.assertEqual(derived.tzname(), 'cookie')
+
     def test_more_bool(self):
         # time is always True.
         cls = self.theclass
@@ -3789,6 +3868,43 @@ class TestDateTimeTZ(TestDateTime, TZInfoBase, unittest.TestCase):
             self.assertEqual(derived.tzname(), 'cookie')
         self.assertEqual(orig.__reduce__(), orig.__reduce_ex__(2))
 
+    def test_compat_unpickle(self):
+        tests = [
+            b'cdatetime\ndatetime\n'
+            b"(S'\\x07\\xdf\\x0b\\x1b\\x14;\\x01\\x01\\xe2@'\n"
+            b'ctest.datetimetester\nPicklableFixedOffset\n(tR'
+            b"(dS'_FixedOffset__offset'\ncdatetime\ntimedelta\n"
+            b'(I-1\nI68400\nI0\ntRs'
+            b"S'_FixedOffset__dstoffset'\nNs"
+            b"S'_FixedOffset__name'\nS'cookie'\nsbtR.",
+
+            b'cdatetime\ndatetime\n'
+            b'(U\n\x07\xdf\x0b\x1b\x14;\x01\x01\xe2@'
+            b'ctest.datetimetester\nPicklableFixedOffset\n)R'
+            b'}(U\x14_FixedOffset__offsetcdatetime\ntimedelta\n'
+            b'(J\xff\xff\xff\xffJ0\x0b\x01\x00K\x00tR'
+            b'U\x17_FixedOffset__dstoffsetN'
+            b'U\x12_FixedOffset__nameU\x06cookieubtR.',
+
+            b'\x80\x02cdatetime\ndatetime\n'
+            b'U\n\x07\xdf\x0b\x1b\x14;\x01\x01\xe2@'
+            b'ctest.datetimetester\nPicklableFixedOffset\n)R'
+            b'}(U\x14_FixedOffset__offsetcdatetime\ntimedelta\n'
+            b'J\xff\xff\xff\xffJ0\x0b\x01\x00K\x00\x87R'
+            b'U\x17_FixedOffset__dstoffsetN'
+            b'U\x12_FixedOffset__nameU\x06cookieub\x86R.',
+        ]
+        args = 2015, 11, 27, 20, 59, 1, 123456
+        tinfo = PicklableFixedOffset(-300, 'cookie')
+        expected = self.theclass(*args, **{'tzinfo': tinfo})
+        for data in tests:
+            for loads in pickle_loads:
+                derived = loads(data, encoding='latin1')
+                self.assertEqual(derived, expected)
+                self.assertIsInstance(derived.tzinfo, PicklableFixedOffset)
+                self.assertEqual(derived.utcoffset(), timedelta(minutes=-300))
+                self.assertEqual(derived.tzname(), 'cookie')
+
     def test_extreme_hashes(self):
         # If an attempt is made to hash these via subtracting the offset
         # then hashing a datetime object, OverflowError results.  The
diff --git a/Misc/NEWS.d/next/Library/2017-10-12-22-39-55.bpo-22005.lGP-sc.rst b/Misc/NEWS.d/next/Library/2017-10-12-22-39-55.bpo-22005.lGP-sc.rst
new file mode 100644
index 0000000000..951098d0a7
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-10-12-22-39-55.bpo-22005.lGP-sc.rst
@@ -0,0 +1,3 @@
+Implemented unpickling instances of :class:`~datetime.datetime`,
+:class:`~datetime.date` and :class:`~datetime.time` pickled by Python 2.
+``encoding='latin1'`` should be used for successful decoding.
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index eb9c35d02d..87a88be609 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -2789,30 +2789,59 @@ static PyGetSetDef date_getset[] = {
 static char *date_kws[] = {"year", "month", "day", NULL};
 
 static PyObject *
+date_from_pickle(PyTypeObject *type, PyObject *state)
+{
+    PyDateTime_Date *me;
+
+    me = (PyDateTime_Date *) (type->tp_alloc(type, 0));
+    if (me != NULL) {
+        const char *pdata = PyBytes_AS_STRING(state);
+        memcpy(me->data, pdata, _PyDateTime_DATE_DATASIZE);
+        me->hashcode = -1;
+    }
+    return (PyObject *)me;
+}
+
+static PyObject *
 date_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 {
     PyObject *self = NULL;
-    PyObject *state;
     int year;
     int month;
     int day;
 
     /* Check for invocation from pickle with __getstate__ state */
-    if (PyTuple_GET_SIZE(args) == 1) {
-        state = PyTuple_GET_ITEM(args, 0);
-        if (PyBytes_Check(state) &&
-            PyBytes_GET_SIZE(state) == _PyDateTime_DATE_DATASIZE &&
-            MONTH_IS_SANE(PyBytes_AS_STRING(state)[2]))
-        {
-            PyDateTime_Date *me;
-
-            me = (PyDateTime_Date *) (type->tp_alloc(type, 0));
-            if (me != NULL) {
-                char *pdata = PyBytes_AS_STRING(state);
-                memcpy(me->data, pdata, _PyDateTime_DATE_DATASIZE);
-                me->hashcode = -1;
+    if (PyTuple_GET_SIZE(args) >= 1) {
+        PyObject *state = PyTuple_GET_ITEM(args, 0);
+        if (PyBytes_Check(state)) {
+            if (PyBytes_GET_SIZE(state) == _PyDateTime_DATE_DATASIZE &&
+                MONTH_IS_SANE(PyBytes_AS_STRING(state)[2]))
+            {
+                return date_from_pickle(type, state);
+            }
+        }
+        else if (PyUnicode_Check(state)) {
+            if (PyUnicode_READY(state)) {
+                return NULL;
+            }
+            if (PyUnicode_GET_LENGTH(state) == _PyDateTime_DATE_DATASIZE &&
+                MONTH_IS_SANE(PyUnicode_READ_CHAR(state, 2)))
+            {
+                state = PyUnicode_AsLatin1String(state);
+                if (state == NULL) {
+                    if (PyErr_ExceptionMatches(PyExc_UnicodeEncodeError)) {
+                        /* More informative error message. */
+                        PyErr_SetString(PyExc_ValueError,
+                            "Failed to encode latin1 string when unpickling "
+                            "a date object. "
+                            "pickle.load(data, encoding='latin1') is assumed.");
+                    }
+                    return NULL;
+                }
+                self = date_from_pickle(type, state);
+                Py_DECREF(state);
+                return self;
             }
-            return (PyObject *)me;
         }
     }
 
@@ -3902,10 +3931,42 @@ static char *time_kws[] = {"hour", "minute", "second", "microsecond",
                            "tzinfo", "fold", NULL};
 
 static PyObject *
+time_from_pickle(PyTypeObject *type, PyObject *state, PyObject *tzinfo)
+{
+    PyDateTime_Time *me;
+    char aware = (char)(tzinfo != Py_None);
+
+    if (aware && check_tzinfo_subclass(tzinfo) < 0) {
+        PyErr_SetString(PyExc_TypeError, "bad tzinfo state arg");
+        return NULL;
+    }
+
+    me = (PyDateTime_Time *) (type->tp_alloc(type, aware));
+    if (me != NULL) {
+        const char *pdata = PyBytes_AS_STRING(state);
+
+        memcpy(me->data, pdata, _PyDateTime_TIME_DATASIZE);
+        me->hashcode = -1;
+        me->hastzinfo = aware;
+        if (aware) {
+            Py_INCREF(tzinfo);
+            me->tzinfo = tzinfo;
+        }
+        if (pdata[0] & (1 << 7)) {
+            me->data[0] -= 128;
+            me->fold = 1;
+        }
+        else {
+            me->fold = 0;
+        }
+    }
+    return (PyObject *)me;
+}
+
+static PyObject *
 time_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 {
     PyObject *self = NULL;
-    PyObject *state;
     int hour = 0;
     int minute = 0;
     int second = 0;
@@ -3914,47 +3975,42 @@ time_new(PyTypeObject *type, PyObject *args, PyObject *kw)
     int fold = 0;
 
     /* Check for invocation from pickle with __getstate__ state */
-    if (PyTuple_GET_SIZE(args) >= 1 &&
-        PyTuple_GET_SIZE(args) <= 2)
-    {
-        state = PyTuple_GET_ITEM(args, 0);
-        if (PyBytes_Check(state) &&
-            PyBytes_GET_SIZE(state) == _PyDateTime_TIME_DATASIZE &&
-            (0x7F & ((unsigned char) (PyBytes_AS_STRING(state)[0]))) < 24)
-        {
-            PyDateTime_Time *me;
-            char aware;
-
-            if (PyTuple_GET_SIZE(args) == 2) {
-                tzinfo = PyTuple_GET_ITEM(args, 1);
-                if (check_tzinfo_subclass(tzinfo) < 0) {
-                    PyErr_SetString(PyExc_TypeError, "bad "
-                        "tzinfo state arg");
-                    return NULL;
-                }
+    if (PyTuple_GET_SIZE(args) >= 1 && PyTuple_GET_SIZE(args) <= 2) {
+        PyObject *state = PyTuple_GET_ITEM(args, 0);
+        if (PyTuple_GET_SIZE(args) == 2) {
+            tzinfo = PyTuple_GET_ITEM(args, 1);
+        }
+        if (PyBytes_Check(state)) {
+            if (PyBytes_GET_SIZE(state) == _PyDateTime_TIME_DATASIZE &&
+                (0x7F & ((unsigned char) (PyBytes_AS_STRING(state)[0]))) < 24)
+            {
+                return time_from_pickle(type, state, tzinfo);
             }
-            aware = (char)(tzinfo != Py_None);
-            me = (PyDateTime_Time *) (type->tp_alloc(type, aware));
-            if (me != NULL) {
-                char *pdata = PyBytes_AS_STRING(state);
-
-                memcpy(me->data, pdata, _PyDateTime_TIME_DATASIZE);
-                me->hashcode = -1;
-                me->hastzinfo = aware;
-                if (aware) {
-                    Py_INCREF(tzinfo);
-                    me->tzinfo = tzinfo;
-                }
-                if (pdata[0] & (1 << 7)) {
-                    me->data[0] -= 128;
-                    me->fold = 1;
-                }
-                else {
-                    me->fold = 0;
+        }
+        else if (PyUnicode_Check(state)) {
+            if (PyUnicode_READY(state)) {
+                return NULL;
+            }
+            if (PyUnicode_GET_LENGTH(state) == _PyDateTime_TIME_DATASIZE &&
+                (0x7F & PyUnicode_READ_CHAR(state, 2)) < 24)
+            {
+                state = PyUnicode_AsLatin1String(state);
+                if (state == NULL) {
+                    if (PyErr_ExceptionMatches(PyExc_UnicodeEncodeError)) {
+                        /* More informative error message. */
+                        PyErr_SetString(PyExc_ValueError,
+                            "Failed to encode latin1 string when unpickling "
+                            "a time object. "
+                            "pickle.load(data, encoding='latin1') is assumed.");
+                    }
+                    return NULL;
                 }
+                self = time_from_pickle(type, state, tzinfo);
+                Py_DECREF(state);
+                return self;
             }
-            return (PyObject *)me;
         }
+        tzinfo = Py_None;
     }
 
     if (PyArg_ParseTupleAndKeywords(args, kw, "|iiiiO$i", time_kws,
@@ -4541,10 +4597,42 @@ static char *datetime_kws[] = {
 };
 
 static PyObject *
+datetime_from_pickle(PyTypeObject *type, PyObject *state, PyObject *tzinfo)
+{
+    PyDateTime_DateTime *me;
+    char aware = (char)(tzinfo != Py_None);
+
+    if (aware && check_tzinfo_subclass(tzinfo) < 0) {
+        PyErr_SetString(PyExc_TypeError, "bad tzinfo state arg");
+        return NULL;
+    }
+
+    me = (PyDateTime_DateTime *) (type->tp_alloc(type , aware));
+    if (me != NULL) {
+        const char *pdata = PyBytes_AS_STRING(state);
+
+        memcpy(me->data, pdata, _PyDateTime_DATETIME_DATASIZE);
+        me->hashcode = -1;
+        me->hastzinfo = aware;
+        if (aware) {
+            Py_INCREF(tzinfo);
+            me->tzinfo = tzinfo;
+        }
+        if (pdata[2] & (1 << 7)) {
+            me->data[2] -= 128;
+            me->fold = 1;
+        }
+        else {
+            me->fold = 0;
+        }
+    }
+    return (PyObject *)me;
+}
+
+static PyObject *
 datetime_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 {
     PyObject *self = NULL;
-    PyObject *state;
     int year;
     int month;
     int day;
@@ -4556,47 +4644,42 @@ datetime_new(PyTypeObject *type, PyObject *args, PyObject *kw)
     PyObject *tzinfo = Py_None;
 
     /* Check for invocation from pickle with __getstate__ state */
-    if (PyTuple_GET_SIZE(args) >= 1 &&
-        PyTuple_GET_SIZE(args) <= 2)
-    {
-        state = PyTuple_GET_ITEM(args, 0);
-        if (PyBytes_Check(state) &&
-            PyBytes_GET_SIZE(state) == _PyDateTime_DATETIME_DATASIZE &&
-            MONTH_IS_SANE(PyBytes_AS_STRING(state)[2] & 0x7F))
-        {
-            PyDateTime_DateTime *me;
-            char aware;
-
-            if (PyTuple_GET_SIZE(args) == 2) {
-                tzinfo = PyTuple_GET_ITEM(args, 1);
-                if (check_tzinfo_subclass(tzinfo) < 0) {
-                    PyErr_SetString(PyExc_TypeError, "bad "
-                        "tzinfo state arg");
-                    return NULL;
-                }
+    if (PyTuple_GET_SIZE(args) >= 1 && PyTuple_GET_SIZE(args) <= 2) {
+        PyObject *state = PyTuple_GET_ITEM(args, 0);
+        if (PyTuple_GET_SIZE(args) == 2) {
+            tzinfo = PyTuple_GET_ITEM(args, 1);
+        }
+        if (PyBytes_Check(state)) {
+            if (PyBytes_GET_SIZE(state) == _PyDateTime_DATETIME_DATASIZE &&
+                MONTH_IS_SANE(PyBytes_AS_STRING(state)[2] & 0x7F))
+            {
+                return datetime_from_pickle(type, state, tzinfo);
             }
-            aware = (char)(tzinfo != Py_None);
-            me = (PyDateTime_DateTime *) (type->tp_alloc(type , aware));
-            if (me != NULL) {
-                char *pdata = PyBytes_AS_STRING(state);
-
-                memcpy(me->data, pdata, _PyDateTime_DATETIME_DATASIZE);
-                me->hashcode = -1;
-                me->hastzinfo = aware;
-                if (aware) {
-                    Py_INCREF(tzinfo);
-                    me->tzinfo = tzinfo;
-                }
-                if (pdata[2] & (1 << 7)) {
-                    me->data[2] -= 128;
-                    me->fold = 1;
-                }
-                else {
-                    me->fold = 0;
+        }
+        else if (PyUnicode_Check(state)) {
+            if (PyUnicode_READY(state)) {
+                return NULL;
+            }
+            if (PyUnicode_GET_LENGTH(state) == _PyDateTime_DATETIME_DATASIZE &&
+                MONTH_IS_SANE(PyUnicode_READ_CHAR(state, 2) & 0x7F))
+            {
+                state = PyUnicode_AsLatin1String(state);
+                if (state == NULL) {
+                    if (PyErr_ExceptionMatches(PyExc_UnicodeEncodeError)) {
+                        /* More informative error message. */
+                        PyErr_SetString(PyExc_ValueError,
+                            "Failed to encode latin1 string when unpickling "
+                            "a datetime object. "
+                            "pickle.load(data, encoding='latin1') is assumed.");
+                    }
+                    return NULL;
                 }
+                self = datetime_from_pickle(type, state, tzinfo);
+                Py_DECREF(state);
+                return self;
             }
-            return (PyObject *)me;
         }
+        tzinfo = Py_None;
     }
 
     if (PyArg_ParseTupleAndKeywords(args, kw, "iii|iiiiO$i", datetime_kws,