Merge branch 'main' into groupby-save-codes-new

* main:
  Preserve `base` and `loffset` arguments in `resample` (pydata#7444)
  ignore the `pkg_resources` deprecation warning (pydata#7594)
  Update contains_cftime_datetimes to avoid loading entire variable array (pydata#7494)
  Support first, last with dask arrays (pydata#7562)
  update the docs environment (pydata#7442)
  Add xCDAT to list of Xarray related projects (pydata#7579)
  [pre-commit.ci] pre-commit autoupdate (pydata#7565)
  fix nczarr when libnetcdf>4.8.1 (pydata#7575)
  use numpys SupportsDtype (pydata#7521)

Author: dcherian

.pre-commit-config.yaml

@@ -16,7 +16,7 @@ repos:
         files: ^xarray/
   - repo: https://github.com/charliermarsh/ruff-pre-commit
     # Ruff version.
-    rev: 'v0.0.248'
+    rev: 'v0.0.253'
     hooks:
       - id: ruff
         args: ["--fix"]

ci/requirements/doc.yml

@@ -4,7 +4,7 @@ channels:
   - conda-forge
   - nodefaults
 dependencies:
-  - python=3.9
+  - python=3.10
   - bottleneck
   - cartopy
   - cfgrib>=0.9
@@ -23,18 +23,17 @@ dependencies:
   - pandas>=1.4
   - pooch
   - pip
-  - pydata-sphinx-theme>=0.4.3
   - pyproj
   - rasterio>=1.1
   - scipy!=1.10.0
   - seaborn
   - setuptools
   - sparse
   - sphinx-autosummary-accessors
-  - sphinx-book-theme >= 0.0.38
+  - sphinx-book-theme >= 0.3.0
   - sphinx-copybutton
   - sphinx-design
-  - sphinx!=4.4.0
+  - sphinx>=5.0
   - zarr>=2.10
   - pip:
       - sphinxext-rediraffe

doc/conf.py

@@ -97,8 +97,8 @@
 
 
 extlinks = {
-    "issue": ("https://github.com/pydata/xarray/issues/%s", "GH"),
-    "pull": ("https://github.com/pydata/xarray/pull/%s", "PR"),
+    "issue": ("https://github.com/pydata/xarray/issues/%s", "GH%s"),
+    "pull": ("https://github.com/pydata/xarray/pull/%s", "PR%s"),
 }
 
 # sphinx-copybutton configurations
@@ -244,12 +244,11 @@
     use_repository_button=True,
     use_issues_button=True,
     home_page_in_toc=False,
-    extra_navbar="",
-    navbar_footer_text="",
     extra_footer="""<p>Xarray is a fiscally sponsored project of <a href="https://numfocus.org">NumFOCUS</a>,
     a nonprofit dedicated to supporting the open-source scientific computing community.<br>
     Theme by the <a href="https://ebp.jupyterbook.org">Executable Book Project</a></p>""",
     twitter_url="https://twitter.com/xarray_devs",
+    icon_links=[],  # workaround for pydata/pydata-sphinx-theme#1220
 )
 
 

doc/ecosystem.rst

@@ -45,6 +45,7 @@ Geosciences
 - `xarray-spatial <https://xarray-spatial.org/>`_: Numba-accelerated raster-based spatial processing tools (NDVI, curvature, zonal-statistics, proximity, hillshading, viewshed, etc.)
 - `xarray-topo <https://xarray-topo.readthedocs.io/>`_: xarray extension for topographic analysis and modelling.
 - `xbpch <https://github.com/darothen/xbpch>`_: xarray interface for bpch files.
+- `xCDAT <https://xcdat.readthedocs.io/>`_: An extension of xarray for climate data analysis on structured grids.
 - `xclim <https://xclim.readthedocs.io/>`_: A library for calculating climate science indices with unit handling built from xarray and dask.
 - `xESMF <https://pangeo-xesmf.readthedocs.io/>`_: Universal regridder for geospatial data.
 - `xgcm <https://xgcm.readthedocs.io/>`_: Extends the xarray data model to understand finite volume grid cells (common in General Circulation Models) and provides interpolation and difference operations for such grids.

doc/user-guide/interpolation.rst

@@ -50,7 +50,7 @@ array-like, which gives the interpolated result as an array.
     # interpolation
     da.interp(time=[2.5, 3.5])
 
-To interpolate data with a :py:doc:`numpy.datetime64 <reference/arrays.datetime>` coordinate you can pass a string.
+To interpolate data with a :py:doc:`numpy.datetime64 <numpy:reference/arrays.datetime>` coordinate you can pass a string.
 
 .. ipython:: python
 

doc/user-guide/weather-climate.rst

@@ -233,7 +233,7 @@ For data indexed by a :py:class:`~xarray.CFTimeIndex` xarray currently supports:
 
 .. ipython:: python
 
-    da.resample(time="81T", closed="right", label="right", base=3).mean()
+    da.resample(time="81T", closed="right", label="right", offset="3T").mean()
 
 .. _Timestamp-valid range: https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#timestamp-limitations
 .. _ISO 8601 standard: https://en.wikipedia.org/wiki/ISO_8601

doc/whats-new.rst

@@ -25,13 +25,22 @@ New Features
 
 - Fix :py:meth:`xr.cov` and :py:meth:`xr.corr` now support complex valued arrays  (:issue:`7340`, :pull:`7392`).
   By `Michael Niklas <https://github.com/headtr1ck>`_.
+- Support dask arrays in ``first`` and ``last`` reductions.
+  By `Deepak Cherian <https://github.com/dcherian>`_.
 
 Breaking changes
 ~~~~~~~~~~~~~~~~
 
 
 Deprecations
 ~~~~~~~~~~~~
+- Following pandas, the ``base`` and ``loffset`` parameters of
+  :py:meth:`xr.DataArray.resample` and :py:meth:`xr.Dataset.resample` have been
+  deprecated and will be removed in a future version of xarray.  Using the
+  ``origin`` or ``offset`` parameters is recommended as a replacement for using
+  the ``base`` parameter and using time offset arithmetic is recommended as a
+  replacement for using the ``loffset`` parameter (:pull:`8459`).  By `Spencer
+  Clark <https://github.com/spencerkclark>`_.
 
 
 Bug fixes
@@ -42,6 +51,8 @@ Bug fixes
 - Fix matplotlib raising a UserWarning when plotting a scatter plot
   with an unfilled marker (:issue:`7313`, :pull:`7318`).
   By `Jimmy Westling <https://github.com/illviljan>`_.
+- Improved performance in ``open_dataset`` for datasets with large object arrays (:issue:`7484`, :pull:`7494`).
+  By `Alex Goodman <https://github.com/agoodm>`_ and `Deepak Cherian <https://github.com/dcherian>`_.
 
 Documentation
 ~~~~~~~~~~~~~

xarray/backends/zarr.py

@@ -207,7 +207,7 @@ def _get_zarr_dims_and_attrs(zarr_obj, dimension_key, try_nczarr):
                 "which are required for xarray to determine variable dimensions."
             ) from e
 
-    nc_attrs = [attr for attr in zarr_obj.attrs if attr.startswith("_NC")]
+    nc_attrs = [attr for attr in zarr_obj.attrs if attr.lower().startswith("_nc")]
     attributes = HiddenKeyDict(zarr_obj.attrs, [dimension_key] + nc_attrs)
     return dimensions, attributes
 
@@ -495,7 +495,7 @@ def get_attrs(self):
         return {
             k: v
             for k, v in self.zarr_group.attrs.asdict().items()
-            if not k.startswith("_NC")
+            if not k.lower().startswith("_nc")
         }
 
     def get_dimensions(self):

xarray/coding/calendar_ops.py

@@ -147,7 +147,7 @@ def convert_calendar(
     from xarray.core.dataarray import DataArray
 
     time = obj[dim]
-    if not _contains_datetime_like_objects(time):
+    if not _contains_datetime_like_objects(time.variable):
         raise ValueError(f"Coordinate {dim} must contain datetime objects.")
 
     use_cftime = _should_cftime_be_used(time, calendar, use_cftime)
@@ -319,8 +319,8 @@ def interp_calendar(source, target, dim="time"):
         target = DataArray(target, dims=(dim,), name=dim)
 
     if not _contains_datetime_like_objects(
-        source[dim]
-    ) or not _contains_datetime_like_objects(target):
+        source[dim].variable
+    ) or not _contains_datetime_like_objects(target.variable):
         raise ValueError(
             f"Both 'source.{dim}' and 'target' must contain datetime objects."
         )

xarray/coding/cftime_offsets.py

@@ -1267,7 +1267,7 @@ def date_range_like(source, calendar, use_cftime=None):
     if not isinstance(source, (pd.DatetimeIndex, CFTimeIndex)) and (
         isinstance(source, DataArray)
         and (source.ndim != 1)
-        or not _contains_datetime_like_objects(source)
+        or not _contains_datetime_like_objects(source.variable)
     ):
         raise ValueError(
             "'source' must be a 1D array of datetime objects for inferring its range."