REF: add Resolution to tslibs.__init__, rename _resolution->_resolution_obj (pandas-dev#34518)

Author: jbrockmendel

pandas/_libs/tslibs/__init__.py

@@ -8,6 +8,7 @@
     "OutOfBoundsDatetime",
     "IncompatibleFrequency",
     "Period",
+    "Resolution",
     "Timedelta",
     "delta_to_nanoseconds",
     "ints_to_pytimedelta",
@@ -20,6 +21,7 @@
 from .nattype import NaT, NaTType, iNaT, is_null_datetimelike, nat_strings
 from .np_datetime import OutOfBoundsDatetime
 from .period import IncompatibleFrequency, Period
+from .resolution import Resolution
 from .timedeltas import Timedelta, delta_to_nanoseconds, ints_to_pytimedelta
 from .timestamps import Timestamp
 from .tzconversion import tz_convert_single

pandas/core/arrays/datetimelike.py

@@ -5,9 +5,16 @@
 
 import numpy as np
 
-from pandas._libs import NaT, NaTType, Period, Timestamp, algos, iNaT, lib
-from pandas._libs.tslibs.resolution import Resolution
-from pandas._libs.tslibs.timedeltas import delta_to_nanoseconds
+from pandas._libs import algos, lib
+from pandas._libs.tslibs import (
+    NaT,
+    NaTType,
+    Period,
+    Resolution,
+    Timestamp,
+    delta_to_nanoseconds,
+    iNaT,
+)
 from pandas._libs.tslibs.timestamps import (
     RoundTo,
     integer_op_not_supported,
@@ -1103,7 +1110,7 @@ def inferred_freq(self):
             return None
 
     @property  # NB: override with cache_readonly in immutable subclasses
-    def _resolution(self) -> Optional[Resolution]:
+    def _resolution_obj(self) -> Optional[Resolution]:
         try:
             return Resolution.get_reso_from_freq(self.freqstr)
         except KeyError:
@@ -1114,12 +1121,12 @@ def resolution(self) -> str:
         """
         Returns day, hour, minute, second, millisecond or microsecond
         """
-        if self._resolution is None:
+        if self._resolution_obj is None:
             if is_period_dtype(self.dtype):
                 # somewhere in the past it was decided we default to day
                 return "day"
             # otherwise we fall through and will raise
-        return Resolution.get_str(self._resolution)
+        return Resolution.get_str(self._resolution_obj)
 
     @classmethod
     def _validate_frequency(cls, index, freq, **kwargs):

pandas/core/arrays/datetimes.py

@@ -537,7 +537,7 @@ def is_normalized(self):
         return conversion.is_date_array_normalized(self.asi8, self.tz)
 
     @property  # NB: override with cache_readonly in immutable subclasses
-    def _resolution(self) -> libresolution.Resolution:
+    def _resolution_obj(self) -> libresolution.Resolution:
         return libresolution.get_resolution(self.asi8, self.tz)
 
     # ----------------------------------------------------------------

pandas/core/indexes/datetimelike.py

@@ -7,7 +7,7 @@
 import numpy as np
 
 from pandas._libs import NaT, Timedelta, iNaT, join as libjoin, lib
-from pandas._libs.tslibs import timezones
+from pandas._libs.tslibs import Resolution, timezones
 from pandas._libs.tslibs.parsing import DateParseError
 from pandas._typing import Label
 from pandas.compat.numpy import function as nv
@@ -78,7 +78,7 @@ def wrapper(left, right):
 
 
 @inherit_names(
-    ["inferred_freq", "_isnan", "_resolution", "resolution"],
+    ["inferred_freq", "_isnan", "_resolution_obj", "resolution"],
     DatetimeLikeArrayMixin,
     cache=True,
 )
@@ -93,7 +93,7 @@ class DatetimeIndexOpsMixin(ExtensionIndex):
     _data: Union[DatetimeArray, TimedeltaArray, PeriodArray]
     freq: Optional[DateOffset]
     freqstr: Optional[str]
-    _resolution: int
+    _resolution_obj: Resolution
     _bool_ops: List[str] = []
     _field_ops: List[str] = []
 

pandas/core/indexes/datetimes.py

@@ -6,7 +6,7 @@
 import numpy as np
 
 from pandas._libs import NaT, Period, Timestamp, index as libindex, lib, tslib
-from pandas._libs.tslibs import fields, parsing, resolution as libresolution, timezones
+from pandas._libs.tslibs import Resolution, fields, parsing, timezones
 from pandas._libs.tslibs.frequencies import get_freq_group
 from pandas._libs.tslibs.offsets import prefix_mapping
 from pandas._typing import DtypeObj, Label
@@ -72,7 +72,9 @@ def _new_DatetimeIndex(cls, d):
     DatetimeArray,
     wrap=True,
 )
-@inherit_names(["_timezone", "is_normalized", "_resolution"], DatetimeArray, cache=True)
+@inherit_names(
+    ["_timezone", "is_normalized", "_resolution_obj"], DatetimeArray, cache=True
+)
 @inherit_names(
     [
         "_bool_ops",
@@ -525,7 +527,7 @@ def _validate_partial_date_slice(self, reso: str):
         if (
             self.is_monotonic
             and reso in ["day", "hour", "minute", "second"]
-            and self._resolution >= libresolution.Resolution.from_attrname(reso)
+            and self._resolution_obj >= Resolution.from_attrname(reso)
         ):
             # These resolution/monotonicity validations came from GH3931,
             # GH3452 and GH2369.

pandas/tests/tslibs/test_api.py

@@ -33,6 +33,7 @@ def test_namespace():
         "OutOfBoundsDatetime",
         "Period",
         "IncompatibleFrequency",
+        "Resolution",
         "Timedelta",
         "Timestamp",
         "delta_to_nanoseconds",