EA: revert treatment of i8values

pandas/core/arrays/datetimelike.py

@@ -611,7 +611,7 @@ def _concat_same_type(cls, to_concat):
 
     def copy(self, deep=False):
         values = self.asi8.copy()
-        return type(self)(values, dtype=self.dtype, freq=self.freq)
+        return type(self)._simple_new(values, dtype=self.dtype, freq=self.freq)
 
     def _values_for_factorize(self):
         return self.asi8, iNaT

pandas/core/arrays/datetimes.py

@@ -236,83 +236,51 @@ class DatetimeArray(dtl.DatetimeLikeArrayMixin,
     _dtype = None  # type: Union[np.dtype, DatetimeTZDtype]
     _freq = None
 
-    def __init__(self, values, dtype=_NS_DTYPE, freq=None, copy=False):
-        if isinstance(values, (ABCSeries, ABCIndexClass)):
-            values = values._values
-
-        if isinstance(values, type(self)):
-            # validation
-            dtz = getattr(dtype, 'tz', None)
-            if dtz and values.tz is None:
-                dtype = DatetimeTZDtype(tz=dtype.tz)
-            elif dtz and values.tz:
-                if not timezones.tz_compare(dtz, values.tz):
-                    msg = (
-                        "Timezone of the array and 'dtype' do not match. "
-                        "'{}' != '{}'"
-                    )
-                    raise TypeError(msg.format(dtz, values.tz))
-            elif values.tz:
-                dtype = values.dtype
-            # freq = validate_values_freq(values, freq)
-            if freq is None:
-                freq = values.freq
-            values = values._data
+    def __init__(self, values, dtype=None, freq=None, copy=False):
+        if freq == "infer":
+            raise ValueError(
+                "Frequency inference not allowed in DatetimeArray.__init__. "
+                "Use 'pd.array()' instead.")
 
-        if not isinstance(values, np.ndarray):
-            msg = (
-                "Unexpected type '{}'. 'values' must be a DatetimeArray "
+        if not hasattr(values, "dtype"):
+            # e.g. list
+            raise ValueError(
+                "Unexpected type '{vals}'. 'values' must be a DatetimeArray "
                 "ndarray, or Series or Index containing one of those."
-            )
-            raise ValueError(msg.format(type(values).__name__))
+                .format(vals=type(values).__name__))
 
-        if values.dtype == 'i8':
-            # for compat with datetime/timedelta/period shared methods,
-            #  we can sometimes get here with int64 values.  These represent
-            #  nanosecond UTC (or tz-naive) unix timestamps
-            values = values.view(_NS_DTYPE)
-
-        if values.dtype != _NS_DTYPE:
-            msg = (
+        if values.dtype == np.bool_:
+            raise ValueError(
                 "The dtype of 'values' is incorrect. Must be 'datetime64[ns]'."
-                " Got {} instead."
-            )
-            raise ValueError(msg.format(values.dtype))
+                " Got {dtype} instead."  .format(dtype=values.dtype))
 
-        dtype = _validate_dt64_dtype(dtype)
-
-        if freq == "infer":
-            msg = (
-                "Frequency inference not allowed in DatetimeArray.__init__. "
-                "Use 'pd.array()' instead."
-            )
-            raise ValueError(msg)
-
-        if copy:
-            values = values.copy()
-        if freq:
-            freq = to_offset(freq)
-        if getattr(dtype, 'tz', None):
-            # https://github.com/pandas-dev/pandas/issues/18595
-            # Ensure that we have a standard timezone for pytz objects.
-            # Without this, things like adding an array of timedeltas and
-            # a  tz-aware Timestamp (with a tz specific to its datetime) will
-            # be incorrect(ish?) for the array as a whole
-            dtype = DatetimeTZDtype(tz=timezones.tz_standardize(dtype.tz))
-
-        self._data = values
-        self._dtype = dtype
-        self._freq = freq
+        arr = type(self)._from_sequence(values, dtype=dtype,
+                                        freq=freq, copy=copy)
+        self._data = arr._data
+        self._freq = arr._freq
+        self._dtype = arr._dtype
 
     @classmethod
-    def _simple_new(cls, values, freq=None, tz=None):
+    def _simple_new(cls, values, freq=None, tz=None, dtype=None):
         """
         we require the we have a dtype compat for the values
         if we are passed a non-dtype compat, then coerce using the constructor
         """
-        dtype = DatetimeTZDtype(tz=tz) if tz else _NS_DTYPE
-
-        return cls(values, freq=freq, dtype=dtype)
+        if tz is not None:
+            # TODO: get tz out of here altogether
+            assert dtype is None
+            tz = timezones.tz_standardize(tz)
+            dtype = DatetimeTZDtype(tz=tz)
+        elif dtype is None:
+            dtype = _NS_DTYPE
+
+        assert isinstance(values, np.ndarray), type(values)
+
+        result = object.__new__(cls)
+        result._data = values.view('datetime64[ns]')
+        result._freq = freq
+        result._dtype = dtype
+        return result
 
     @classmethod
     def _from_sequence(cls, data, dtype=None, copy=False,

pandas/core/frame.py

@@ -4377,7 +4377,8 @@ def _maybe_casted_values(index, labels=None):
                             values, mask, np.nan)
 
                     if issubclass(values_type, DatetimeLikeArray):
-                        values = values_type(values, dtype=values_dtype)
+                        values = values_type._simple_new(values,
+                                                         dtype=values_dtype)
 
             return values
 

pandas/core/indexes/datetimes.py

@@ -316,18 +316,18 @@ def _simple_new(cls, values, name=None, freq=None, tz=None, dtype=None):
                 tz = validate_tz_from_dtype(dtype, tz)
                 dtype = DatetimeTZDtype(tz=tz)
             elif dtype is None:
-                dtype = _NS_DTYPE
+                dtype = values.dtype
 
             values = DatetimeArray(values, freq=freq, dtype=dtype)
             tz = values.tz
             freq = values.freq
             values = values._data
+        else:
+            tz = tz or getattr(dtype, 'tz', None)
 
         # DatetimeArray._simple_new will accept either i8 or M8[ns] dtypes
-        if isinstance(values, DatetimeIndex):
-            values = values._data
+        assert isinstance(values, np.ndarray)
         dtarr = DatetimeArray._simple_new(values, freq=freq, tz=tz)
-        assert isinstance(dtarr, DatetimeArray)
 
         result = object.__new__(cls)
         result._data = dtarr

pandas/core/internals/blocks.py

@@ -3078,7 +3078,7 @@ def make_block(values, placement, klass=None, ndim=None, dtype=None,
     elif klass is DatetimeTZBlock and not is_datetime64tz_dtype(values):
         # TODO: This is no longer hit internally; does it need to be retained
         #  for e.g. pyarrow?
-        values = DatetimeArray(values, dtype)
+        values = DatetimeArray(values.view('i8'), dtype)
 
     return klass(values, ndim=ndim, placement=placement)
 

pandas/io/packers.py

@@ -656,7 +656,9 @@ def create_block(b):
             if is_datetime64tz_dtype(b[u'dtype']):
                 assert isinstance(values, np.ndarray), type(values)
                 assert values.dtype == 'M8[ns]', values.dtype
-                values = DatetimeArray(values, dtype=b[u'dtype'])
+                # These values are interpreted as unix timestamps, so we
+                #  view as i8
+                values = DatetimeArray(values.view('i8'), dtype=b[u'dtype'])
 
             return make_block(values=values,
                               klass=getattr(internals, b[u'klass']),

pandas/tests/arrays/test_datetimelike.py

@@ -340,7 +340,7 @@ def test_from_array_keeps_base(self):
         arr = np.array(['2000-01-01', '2000-01-02'], dtype='M8[ns]')
         dta = DatetimeArray(arr)
 
-        assert dta._data is arr
+        assert dta._data.base is arr
         dta = DatetimeArray(arr[:0])
         assert dta._data.base is arr
 

pandas/tests/arrays/test_datetimes.py

@@ -16,7 +16,68 @@
 
 
 class TestDatetimeArrayConstructor(object):
+
+    @pytest.mark.parametrize('tz', [None, 'Asia/Singapore'])
+    def test_constructor_equivalence(self, tz):
+        # GH#24623 check that DatetimeArray.__init__ behavior matches:
+        #   Timestamp.__new__             for int64
+        #   DatetimeArray._from_sequence  for int64, datetime64[ns]
+        #   DatetimeArray._simple_new     for int64
+        #   DatetimeIndex.__new__         for int64, datetime64[ns]
+        #   DatetimeIndex._simple_new     for int64, datetime64[ns]
+        #
+        # and that DatetimeArray._simple_new behaves like
+        #  DatetimeIndex._simple_new for both int64 and datetime64[ns] inputs
+        arr = np.random.randint(-10**9, 10**9, size=5, dtype=np.int64)
+        dti = pd.date_range('1960-01-01', periods=1, tz=tz)
+
+        v1 = DatetimeArray._simple_new(arr.view('i8'), dtype=dti.dtype)
+        v2 = DatetimeArray(arr.view('i8'), dtype=dti.dtype)
+        v3 = DatetimeArray._from_sequence(arr.view('i8'), dtype=dti.dtype)
+        v4 = pd.DatetimeIndex._simple_new(arr.view('i8'), tz=dti.tz)
+        v5 = pd.DatetimeIndex(arr.view('i8'), tz=dti.tz)
+        v6 = pd.to_datetime(arr, utc=True).tz_convert(dti.tz)
+
+        # when dealing with _simple_new, i8 and M8[ns] are interchangeable
+        v7 = DatetimeArray._simple_new(arr.view('M8[ns]'), dtype=dti.dtype)
+        v8 = pd.DatetimeIndex._simple_new(arr.view('M8[ns]'), dtype=dti.dtype)
+
+        tm.assert_datetime_array_equal(v1, v2)
+        tm.assert_datetime_array_equal(v1, v3)
+        tm.assert_datetime_array_equal(v1, v4._data)
+        tm.assert_datetime_array_equal(v1, v5._data)
+        tm.assert_datetime_array_equal(v1, v6._data)
+        tm.assert_datetime_array_equal(v1, v7)
+        tm.assert_datetime_array_equal(v1, v8._data)
+
+        expected = [pd.Timestamp(i8, tz=dti.tz) for i8 in arr]
+        assert list(v1) == expected
+
+        # The guarantees for datetime64 data are fewer
+        dt64arr = arr.view('datetime64[ns]')
+        v1 = DatetimeArray(dt64arr, dtype=dti.dtype)
+        v2 = DatetimeArray._from_sequence(dt64arr, dtype=dti.dtype)
+        v3 = DatetimeArray._from_sequence(dt64arr, tz=dti.tz)
+        v4 = pd.DatetimeIndex(dt64arr, dtype=dti.dtype)
+        v5 = pd.DatetimeIndex(dt64arr, tz=dti.tz)
+
+        tm.assert_datetime_array_equal(v1, v2)
+        tm.assert_datetime_array_equal(v1, v3)
+        tm.assert_datetime_array_equal(v1, v4._data)
+        tm.assert_datetime_array_equal(v1, v5._data)
+
+    def test_freq_validation(self):
+        # GH#24623 check that invalid instances cannot be created with the
+        #  public constructor
+        arr = pd.array(np.arange(5, dtype=np.int64)) * 3600 * 10**9
+
+        msg = ("Inferred frequency H from passed values does not "
+               "conform to passed frequency W-SUN")
+        with pytest.raises(ValueError, match=msg):
+            DatetimeArray(arr, freq="W")
+
     def test_from_pandas_array(self):
+        # GH#24623, GH#24615
         arr = pd.array(np.arange(5, dtype=np.int64)) * 3600 * 10**9
 
         result = DatetimeArray._from_sequence(arr, freq='infer')
@@ -28,7 +89,8 @@ def test_mismatched_timezone_raises(self):
         arr = DatetimeArray(np.array(['2000-01-01T06:00:00'], dtype='M8[ns]'),
                             dtype=DatetimeTZDtype(tz='US/Central'))
         dtype = DatetimeTZDtype(tz='US/Eastern')
-        with pytest.raises(TypeError, match='Timezone of the array'):
+        with pytest.raises(TypeError,
+                           match='data is already tz-aware US/Central'):
             DatetimeArray(arr, dtype=dtype)
 
     def test_non_array_raises(self):
@@ -51,10 +113,11 @@ def test_freq_infer_raises(self):
     def test_copy(self):
         data = np.array([1, 2, 3], dtype='M8[ns]')
         arr = DatetimeArray(data, copy=False)
-        assert arr._data is data
+        assert arr._data.base is data
 
         arr = DatetimeArray(data, copy=True)
         assert arr._data is not data
+        assert arr._data.base is not data
 
 
 class TestDatetimeArrayComparisons(object):

pandas/tests/test_base.py

@@ -1241,7 +1241,7 @@ def test_numpy_array_all_dtypes(any_numpy_dtype):
     # tz-aware Datetime
     (DatetimeArray(np.array(['2000-01-01T12:00:00',
                              '2000-01-02T12:00:00'],
-                            dtype='M8[ns]'),
+                            dtype='M8[ns]').view('i8'),
                    dtype=DatetimeTZDtype(tz="US/Central")),
      '_data'),
 ])
@@ -1255,7 +1255,7 @@ def test_array(array, attr, box):
         array = getattr(array, attr)
         result = getattr(result, attr)
 
-    assert result is array
+    assert result is array or result.base is array.base
 
 
 def test_array_multiindex_raises():
@@ -1282,7 +1282,7 @@ def test_array_multiindex_raises():
     # tz-aware stays tz`-aware
     (DatetimeArray(np.array(['2000-01-01T06:00:00',
                              '2000-01-02T06:00:00'],
-                            dtype='M8[ns]'),
+                            dtype='M8[ns]').view('i8'),
                    dtype=DatetimeTZDtype(tz='US/Central')),
      np.array([pd.Timestamp('2000-01-01', tz='US/Central'),
                pd.Timestamp('2000-01-02', tz='US/Central')])),