Revert "Merge branch 'main' into asv-benchmark-cron"

This reverts commit aeab4ca, reversing changes made to d1aeeda.
pydata · dcherian · Oct 24, 2021 · Sep 14, 2021 · Sep 14, 2021 · Sep 14, 2021
commit aad08ac8cc570eb3e4156d1d2525e2adb2699d8d
diff --git a/doc/conf.py b/doc/conf.py
@@ -260,8 +260,8 @@
 ogp_image = "https://xarray.pydata.org/en/stable/_static/dataset-diagram-logo.png"
 ogp_custom_meta_tags = [
     '<meta name="twitter:card" content="summary_large_image" />',
-    '<meta property="twitter:site" content="@xarray_dev" />',
-    '<meta name="image" property="og:image" content="https://xarray.pydata.org/en/stable/_static/dataset-diagram-logo.png" />',
+    '<meta property="twitter:site" content="@xarray_dev />',
+    '<meta name="image" property="og:image" content="https://xarray.pydata.org/en/stable/_static/dataset-diagram-logo.png">',
 ]
 
 # Redirects for pages that were moved to new locations

diff --git a/doc/whats-new.rst b/doc/whats-new.rst
@@ -26,15 +26,14 @@ New Features
   By `Pushkar Kopparla <https://github.com/pkopparla>`_.
 - Xarray now does a better job rendering variable names that are long LaTeX sequences when plotting (:issue:`5681`, :pull:`5682`).
   By `Tomas Chor <https://github.com/tomchor>`_.
-- Add an option to disable the use of ``bottleneck`` (:pull:`5560`)
+- Add a option to disable the use of ``bottleneck`` (:pull:`5560`)
   By `Justus Magin <https://github.com/keewis>`_.
 - Added ``**kwargs`` argument to :py:meth:`open_rasterio` to access overviews (:issue:`3269`).
   By `Pushkar Kopparla <https://github.com/pkopparla>`_.
 - Added ``storage_options`` argument to :py:meth:`to_zarr` (:issue:`5601`).
   By `Ray Bell <https://github.com/raybellwaves>`_, `Zachary Blackwood <https://github.com/blackary>`_ and
   `Nathan Lis <https://github.com/wxman22>`_.
-- Histogram plots are set with a title displaying the scalar coords if any, similarly to the other plots (:issue:`5791`, :pull:`5792`).
-  By `Maxime Liquet <https://github.com/maximlt>`_.
+
 
 Breaking changes
 ~~~~~~~~~~~~~~~~
@@ -59,9 +58,6 @@ Deprecations
 
 Bug fixes
 ~~~~~~~~~
-- Fixed performance bug where ``cftime`` import attempted within various core operations if ``cftime`` not
-  installed (:pull:`5640`).
-  By `Luke Sewell <https://github.com/lusewell>`_
 
 - Numbers are properly formatted in a plot's title (:issue:`5788`, :pull:`5789`).
   By `Maxime Liquet <https://github.com/maximlt>`_.
@@ -88,10 +84,6 @@ Internal Changes
   By `Jimmy Westling <https://github.com/illviljan>`_.
 - Use isort's `float_to_top` config. (:pull:`5695`).
   By `Maximilian Roos <https://github.com/max-sixty>`_.
-- Refactor `xarray.core.duck_array_ops` to no longer special-case dispatching to
-  dask versions of functions when acting on dask arrays, instead relying numpy
-  and dask's adherence to NEP-18 to dispatch automatically. (:pull:`5571`)
-  By `Tom Nicholas <https://github.com/TomNicholas>`_.
 - Add an ASV benchmark CI and improve performance of the benchmarks (:pull:`5796`)
   By `Jimmy Westling <https://github.com/illviljan>`_.
 

diff --git a/xarray/coding/cftime_offsets.py b/xarray/coding/cftime_offsets.py
@@ -52,15 +52,12 @@
 from .cftimeindex import CFTimeIndex, _parse_iso8601_with_reso
 from .times import format_cftime_datetime
 
-try:
-    import cftime
-except ImportError:
-    cftime = None
-
 
 def get_date_type(calendar):
     """Return the cftime date type for a given calendar name."""
-    if cftime is None:
+    try:
+        import cftime
+    except ImportError:
         raise ImportError("cftime is required for dates with non-standard calendars")
     else:
         calendars = {
@@ -102,8 +99,7 @@ def __add__(self, other):
         return self.__apply__(other)
 
     def __sub__(self, other):
-        if cftime is None:
-            raise ModuleNotFoundError("No module named 'cftime'")
+        import cftime
 
         if isinstance(other, cftime.datetime):
             raise TypeError("Cannot subtract a cftime.datetime from a time offset.")
@@ -225,8 +221,7 @@ def _adjust_n_years(other, n, month, reference_day):
 
 def _shift_month(date, months, day_option="start"):
     """Shift the date to a month start or end a given number of months away."""
-    if cftime is None:
-        raise ModuleNotFoundError("No module named 'cftime'")
+    import cftime
 
     delta_year = (date.month + months) // 12
     month = (date.month + months) % 12
@@ -383,8 +378,7 @@ def onOffset(self, date):
         return mod_month == 0 and date.day == self._get_offset_day(date)
 
     def __sub__(self, other):
-        if cftime is None:
-            raise ModuleNotFoundError("No module named 'cftime'")
+        import cftime
 
         if isinstance(other, cftime.datetime):
             raise TypeError("Cannot subtract cftime.datetime from offset.")
@@ -469,8 +463,7 @@ def __apply__(self, other):
         return _shift_month(other, months, self._day_option)
 
     def __sub__(self, other):
-        if cftime is None:
-            raise ModuleNotFoundError("No module named 'cftime'")
+        import cftime
 
         if isinstance(other, cftime.datetime):
             raise TypeError("Cannot subtract cftime.datetime from offset.")
@@ -695,8 +688,7 @@ def to_offset(freq):
 
 
 def to_cftime_datetime(date_str_or_date, calendar=None):
-    if cftime is None:
-        raise ModuleNotFoundError("No module named 'cftime'")
+    import cftime
 
     if isinstance(date_str_or_date, str):
         if calendar is None:
@@ -732,8 +724,7 @@ def _maybe_normalize_date(date, normalize):
 def _generate_linear_range(start, end, periods):
     """Generate an equally-spaced sequence of cftime.datetime objects between
     and including two dates (whose length equals the number of periods)."""
-    if cftime is None:
-        raise ModuleNotFoundError("No module named 'cftime'")
+    import cftime
 
     total_seconds = (end - start).total_seconds()
     values = np.linspace(0.0, total_seconds, periods, endpoint=True)

diff --git a/xarray/coding/cftimeindex.py b/xarray/coding/cftimeindex.py
@@ -54,12 +54,6 @@
 from ..core.options import OPTIONS
 from .times import _STANDARD_CALENDARS, cftime_to_nptime, infer_calendar_name
 
-try:
-    import cftime
-except ImportError:
-    cftime = None
-
-
 # constants for cftimeindex.repr
 CFTIME_REPR_LENGTH = 19
 ITEMS_IN_REPR_MAX_ELSE_ELLIPSIS = 100
@@ -120,8 +114,7 @@ def parse_iso8601_like(datetime_string):
 
 
 def _parse_iso8601_with_reso(date_type, timestr):
-    if cftime is None:
-        raise ModuleNotFoundError("No module named 'cftime'")
+    import cftime
 
     default = date_type(1, 1, 1)
     result = parse_iso8601_like(timestr)
@@ -196,8 +189,7 @@ def _field_accessor(name, docstring=None, min_cftime_version="0.0"):
     """Adapted from pandas.tseries.index._field_accessor"""
 
     def f(self, min_cftime_version=min_cftime_version):
-        if cftime is None:
-            raise ModuleNotFoundError("No module named 'cftime'")
+        import cftime
 
         version = cftime.__version__
 
@@ -223,8 +215,7 @@ def get_date_type(self):
 
 
 def assert_all_valid_date_type(data):
-    if cftime is None:
-        raise ModuleNotFoundError("No module named 'cftime'")
+    import cftime
 
     if len(data) > 0:
         sample = data[0]

diff --git a/xarray/coding/times.py b/xarray/coding/times.py
@@ -22,11 +22,6 @@
     unpack_for_encoding,
 )
 
-try:
-    import cftime
-except ImportError:
-    cftime = None
-
 # standard calendars recognized by cftime
 _STANDARD_CALENDARS = {"standard", "gregorian", "proleptic_gregorian"}
 
@@ -169,8 +164,8 @@ def _decode_cf_datetime_dtype(data, units, calendar, use_cftime):
 
 
 def _decode_datetime_with_cftime(num_dates, units, calendar):
-    if cftime is None:
-        raise ModuleNotFoundError("No module named 'cftime'")
+    import cftime
+
     return np.asarray(
         cftime.num2date(num_dates, units, calendar, only_use_cftime_datetimes=True)
     )
@@ -419,8 +414,7 @@ def _encode_datetime_with_cftime(dates, units, calendar):
     This method is more flexible than xarray's parsing using datetime64[ns]
     arrays but also slower because it loops over each element.
     """
-    if cftime is None:
-        raise ModuleNotFoundError("No module named 'cftime'")
+    import cftime
 
     if np.issubdtype(dates.dtype, np.datetime64):
         # numpy's broken datetime conversion only works for us precision

diff --git a/xarray/core/combine.py b/xarray/core/combine.py
@@ -1,7 +1,6 @@
 import itertools
 import warnings
 from collections import Counter
-from typing import Iterable, Sequence, Union
 
 import pandas as pd
 
@@ -370,23 +369,16 @@ def _nested_combine(
     return combined
 
 
-# Define type for arbitrarily-nested list of lists recursively
-# Currently mypy cannot handle this but other linters can (https://stackoverflow.com/a/53845083/3154101)
-DATASET_HYPERCUBE = Union[Dataset, Iterable["DATASET_HYPERCUBE"]]  # type: ignore
-
-
 def combine_nested(
-    datasets: DATASET_HYPERCUBE,
-    concat_dim: Union[
-        str, DataArray, None, Sequence[Union[str, "DataArray", pd.Index, None]]
-    ],
-    compat: str = "no_conflicts",
-    data_vars: str = "all",
-    coords: str = "different",
-    fill_value: object = dtypes.NA,
-    join: str = "outer",
-    combine_attrs: str = "drop",
-) -> Dataset:
+    datasets,
+    concat_dim,
+    compat="no_conflicts",
+    data_vars="all",
+    coords="different",
+    fill_value=dtypes.NA,
+    join="outer",
+    combine_attrs="drop",
+):
     """
     Explicitly combine an N-dimensional grid of datasets into one by using a
     succession of concat and merge operations along each dimension of the grid.
@@ -659,17 +651,16 @@ def _combine_single_variable_hypercube(
 
 # TODO remove empty list default param after version 0.21, see PR4696
 def combine_by_coords(
-    data_objects: Sequence[Union[Dataset, DataArray]] = [],
-    compat: str = "no_conflicts",
-    data_vars: str = "all",
-    coords: str = "different",
-    fill_value: object = dtypes.NA,
-    join: str = "outer",
-    combine_attrs: str = "no_conflicts",
-    datasets: Sequence[Dataset] = None,
-) -> Union[Dataset, DataArray]:
+    data_objects=[],
+    compat="no_conflicts",
+    data_vars="all",
+    coords="different",
+    fill_value=dtypes.NA,
+    join="outer",
+    combine_attrs="no_conflicts",
+    datasets=None,
+):
     """
-
     Attempt to auto-magically combine the given datasets (or data arrays)
     into one by using dimension coordinates.
 
@@ -764,7 +755,7 @@ def combine_by_coords(
 
     Returns
     -------
-    combined : xarray.Dataset or xarray.DataArray
+    combined : xarray.Dataset
 
     See also
     --------

diff --git a/xarray/core/common.py b/xarray/core/common.py
@@ -31,11 +31,6 @@
 from .rolling_exp import RollingExp
 from .utils import Frozen, either_dict_or_kwargs, is_scalar
 
-try:
-    import cftime
-except ImportError:
-    cftime = None
-
 # Used as a sentinel value to indicate a all dimensions
 ALL_DIMS = ...
 
@@ -1825,7 +1820,9 @@ def is_np_timedelta_like(dtype: DTypeLike) -> bool:
 
 def _contains_cftime_datetimes(array) -> bool:
     """Check if an array contains cftime.datetime objects"""
-    if cftime is None:
+    try:
+        from cftime import datetime as cftime_datetime
+    except ImportError:
         return False
     else:
         if array.dtype == np.dtype("O") and array.size > 0:
@@ -1834,7 +1831,7 @@ def _contains_cftime_datetimes(array) -> bool:
                 sample = sample.compute()
                 if isinstance(sample, np.ndarray):
                     sample = sample.item()
-            return isinstance(sample, cftime.datetime)
+            return isinstance(sample, cftime_datetime)
         else:
             return False