From f68b2bf995ce2fa31bae10c163694b1bc63a0057 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Sat, 20 Feb 2021 09:57:45 -0800
Subject: [PATCH 1/2] REF: share _maybe_coerce_values

---
 pandas/core/internals/blocks.py | 68 ++++++++++-----------------------
 1 file changed, 20 insertions(+), 48 deletions(-)

diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index 1377928f71915..d341ce4906ab1 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -17,7 +17,6 @@
 
 from pandas._libs import (
     Interval,
-    NaT,
     Period,
     Timestamp,
     algos as libalgos,
@@ -44,6 +43,7 @@
     maybe_downcast_numeric,
     maybe_downcast_to_dtype,
     maybe_upcast,
+    sanitize_to_nanoseconds,
     soft_convert_objects,
 )
 from pandas.core.dtypes.common import (
@@ -71,6 +71,7 @@
 from pandas.core.dtypes.missing import (
     is_valid_na_for_dtype,
     isna,
+    na_value_for_dtype,
 )
 
 import pandas.core.algorithms as algos
@@ -98,7 +99,10 @@
 )
 from pandas.core.base import PandasObject
 import pandas.core.common as com
-from pandas.core.construction import extract_array
+from pandas.core.construction import (
+    ensure_wrapped_if_datetimelike,
+    extract_array,
+)
 from pandas.core.indexers import (
     check_setitem_lengths,
     is_empty_indexer,
@@ -2081,7 +2085,6 @@ def fillna(
 class DatetimeLikeBlockMixin(NDArrayBackedExtensionBlock):
     """Mixin class for DatetimeBlock, DatetimeTZBlock, and TimedeltaBlock."""
 
-    _dtype: np.dtype
     _holder: Type[Union[DatetimeArray, TimedeltaArray]]
 
     @classmethod
@@ -2098,25 +2101,26 @@ def _maybe_coerce_values(cls, values):
         Returns
         -------
         values : ndarray[datetime64ns/timedelta64ns]
-
-        Overridden by DatetimeTZBlock.
         """
-        if values.dtype != cls._dtype:
-            # non-nano we will convert to nano
-            if values.dtype.kind != cls._dtype.kind:
-                # caller is responsible for ensuring td64/dt64 dtype
-                raise TypeError(values.dtype)  # pragma: no cover
-
-            values = cls._holder._from_sequence(values)._data
-
-        if isinstance(values, cls._holder):
+        values = extract_array(values, extract_numpy=True)
+        if isinstance(values, np.ndarray):
+            values = sanitize_to_nanoseconds(values)
+        elif isinstance(values.dtype, np.dtype):
+            # i.e. not datetime64tz
             values = values._data
 
-        assert isinstance(values, np.ndarray), type(values)
         return values
 
     def array_values(self):
-        return self._holder._simple_new(self.values)
+        return ensure_wrapped_if_datetimelike(self.values)
+
+    @property
+    def _holder(self):
+        return type(self.array_values())
+
+    @property
+    def fill_value(self):
+        return na_value_for_dtype(self.dtype)
 
     def to_native_types(self, na_rep="NaT", **kwargs):
         """ convert to our native types format """
@@ -2129,9 +2133,6 @@ def to_native_types(self, na_rep="NaT", **kwargs):
 class DatetimeBlock(DatetimeLikeBlockMixin):
     __slots__ = ()
     is_datetime = True
-    fill_value = np.datetime64("NaT", "ns")
-    _dtype = fill_value.dtype
-    _holder = DatetimeArray
 
     @property
     def _can_hold_na(self):
@@ -2154,42 +2155,16 @@ class DatetimeTZBlock(ExtensionBlock, DatetimeBlock):
     __slots__ = ()
     is_extension = True
 
-    _holder = DatetimeArray
-
     internal_values = Block.internal_values
     _can_hold_element = DatetimeBlock._can_hold_element
     to_native_types = DatetimeBlock.to_native_types
     diff = DatetimeBlock.diff
-    fill_value = NaT
     where = DatetimeBlock.where
     putmask = DatetimeLikeBlockMixin.putmask
     fillna = DatetimeLikeBlockMixin.fillna
 
     array_values = ExtensionBlock.array_values
 
-    @classmethod
-    def _maybe_coerce_values(cls, values):
-        """
-        Input validation for values passed to __init__. Ensure that
-        we have datetime64TZ, coercing if necessary.
-
-        Parameters
-        ----------
-        values : array-like
-            Must be convertible to datetime64
-
-        Returns
-        -------
-        values : DatetimeArray
-        """
-        if not isinstance(values, cls._holder):
-            values = cls._holder(values)
-
-        if values.tz is None:
-            raise ValueError("cannot create a DatetimeTZBlock without a tz")
-
-        return values
-
     @property
     def is_view(self) -> bool:
         """ return a boolean if I am possibly a view """
@@ -2207,9 +2182,6 @@ class TimeDeltaBlock(DatetimeLikeBlockMixin):
     __slots__ = ()
     _can_hold_na = True
     is_numeric = False
-    _holder = TimedeltaArray
-    fill_value = np.timedelta64("NaT", "ns")
-    _dtype = fill_value.dtype
 
 
 class ObjectBlock(Block):

From 44cc274a4135c46f2c46924bfef92f7a7fda1f63 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Sat, 20 Feb 2021 11:22:49 -0800
Subject: [PATCH 2/2] mypy fixup

---
 pandas/core/internals/blocks.py | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index d341ce4906ab1..ef6b7e524a962 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -95,7 +95,6 @@
     DatetimeArray,
     ExtensionArray,
     PandasArray,
-    TimedeltaArray,
 )
 from pandas.core.base import PandasObject
 import pandas.core.common as com
@@ -2085,8 +2084,6 @@ def fillna(
 class DatetimeLikeBlockMixin(NDArrayBackedExtensionBlock):
     """Mixin class for DatetimeBlock, DatetimeTZBlock, and TimedeltaBlock."""
 
-    _holder: Type[Union[DatetimeArray, TimedeltaArray]]
-
     @classmethod
     def _maybe_coerce_values(cls, values):
         """