From c77bfe531ae1bb0d01e81c38f73cfabc0d48c34c Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Mon, 6 Jan 2020 11:07:33 -0800
Subject: [PATCH 1/2] REF: share _validate_fill_value

---
 pandas/core/arrays/datetimelike.py | 12 +++++++++++-
 pandas/core/arrays/datetimes.py    | 15 ---------------
 pandas/core/arrays/period.py       | 13 +------------
 pandas/core/arrays/timedeltas.py   | 11 -----------
 4 files changed, 12 insertions(+), 39 deletions(-)

diff --git a/pandas/core/arrays/datetimelike.py b/pandas/core/arrays/datetimelike.py
index b9a6daf7c630a..9e5900469b731 100644
--- a/pandas/core/arrays/datetimelike.py
+++ b/pandas/core/arrays/datetimelike.py
@@ -591,7 +591,17 @@ def _validate_fill_value(self, fill_value):
         ------
         ValueError
         """
-        raise AbstractMethodError(self)
+        if isna(fill_value):
+            fill_value = iNaT
+        elif isinstance(fill_value, self._recognized_scalars):
+            self._check_compatible_with(fill_value)
+            fill_value = self._scalar_type(fill_value)
+            fill_value = self._unbox_scalar(fill_value)
+        else:
+            raise ValueError(
+                f"'fill_value' should be a {self._scalar_type}. " "Got '{fill_value}'."
+            )
+        return fill_value
 
     def take(self, indices, allow_fill=False, fill_value=None):
         if allow_fill:
diff --git a/pandas/core/arrays/datetimes.py b/pandas/core/arrays/datetimes.py
index 06d280a3dc25b..267780219c74e 100644
--- a/pandas/core/arrays/datetimes.py
+++ b/pandas/core/arrays/datetimes.py
@@ -20,7 +20,6 @@
 )
 import pandas.compat as compat
 from pandas.errors import PerformanceWarning
-from pandas.util._decorators import Appender
 
 from pandas.core.dtypes.common import (
     _INT64_DTYPE,
@@ -700,20 +699,6 @@ def astype(self, dtype, copy=True):
             return self.to_period(freq=dtype.freq)
         return dtl.DatetimeLikeArrayMixin.astype(self, dtype, copy)
 
-    # ----------------------------------------------------------------
-    # ExtensionArray Interface
-
-    @Appender(dtl.DatetimeLikeArrayMixin._validate_fill_value.__doc__)
-    def _validate_fill_value(self, fill_value):
-        if isna(fill_value):
-            fill_value = iNaT
-        elif isinstance(fill_value, (datetime, np.datetime64)):
-            self._assert_tzawareness_compat(fill_value)
-            fill_value = Timestamp(fill_value).value
-        else:
-            raise ValueError(f"'fill_value' should be a Timestamp. Got '{fill_value}'.")
-        return fill_value
-
     # -----------------------------------------------------------------
     # Rendering Methods
 
diff --git a/pandas/core/arrays/period.py b/pandas/core/arrays/period.py
index e7e1c84b1c070..2b92d6f1cdbe3 100644
--- a/pandas/core/arrays/period.py
+++ b/pandas/core/arrays/period.py
@@ -21,7 +21,7 @@
 )
 from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
 import pandas.compat as compat
-from pandas.util._decorators import Appender, cache_readonly
+from pandas.util._decorators import cache_readonly
 
 from pandas.core.dtypes.common import (
     _TD_DTYPE,
@@ -505,17 +505,6 @@ def to_timestamp(self, freq=None, how="start"):
     # --------------------------------------------------------------------
     # Array-like / EA-Interface Methods
 
-    @Appender(dtl.DatetimeLikeArrayMixin._validate_fill_value.__doc__)
-    def _validate_fill_value(self, fill_value):
-        if isna(fill_value):
-            fill_value = iNaT
-        elif isinstance(fill_value, Period):
-            self._check_compatible_with(fill_value)
-            fill_value = fill_value.ordinal
-        else:
-            raise ValueError(f"'fill_value' should be a Period. Got '{fill_value}'.")
-        return fill_value
-
     def _values_for_argsort(self):
         return self._data
 
diff --git a/pandas/core/arrays/timedeltas.py b/pandas/core/arrays/timedeltas.py
index ddf3af538874e..616f7b63ab25c 100644
--- a/pandas/core/arrays/timedeltas.py
+++ b/pandas/core/arrays/timedeltas.py
@@ -13,7 +13,6 @@
 )
 import pandas.compat as compat
 from pandas.compat.numpy import function as nv
-from pandas.util._decorators import Appender
 
 from pandas.core.dtypes.common import (
     _NS_DTYPE,
@@ -367,16 +366,6 @@ def _maybe_clear_freq(self):
     # ----------------------------------------------------------------
     # Array-Like / EA-Interface Methods
 
-    @Appender(dtl.DatetimeLikeArrayMixin._validate_fill_value.__doc__)
-    def _validate_fill_value(self, fill_value):
-        if isna(fill_value):
-            fill_value = iNaT
-        elif isinstance(fill_value, (timedelta, np.timedelta64, Tick)):
-            fill_value = Timedelta(fill_value).value
-        else:
-            raise ValueError(f"'fill_value' should be a Timedelta. Got '{fill_value}'.")
-        return fill_value
-
     def astype(self, dtype, copy=True):
         # We handle
         #   --> timedelta64[ns]

From 5afe957a4b3786a1aeb2ba2abc790fa6d8e4fc68 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Mon, 6 Jan 2020 11:08:56 -0800
Subject: [PATCH 2/2] post-black fixup

---
 pandas/core/arrays/datetimelike.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/arrays/datetimelike.py b/pandas/core/arrays/datetimelike.py
index 9e5900469b731..b0985332092ae 100644
--- a/pandas/core/arrays/datetimelike.py
+++ b/pandas/core/arrays/datetimelike.py
@@ -599,7 +599,7 @@ def _validate_fill_value(self, fill_value):
             fill_value = self._unbox_scalar(fill_value)
         else:
             raise ValueError(
-                f"'fill_value' should be a {self._scalar_type}. " "Got '{fill_value}'."
+                f"'fill_value' should be a {self._scalar_type}. Got '{fill_value}'."
             )
         return fill_value