Static typing for popular accessors

.github/workflows/cache-pixi-lock.yml

@@ -29,7 +29,7 @@ jobs:
         with:
           path: |
             pixi.lock
-          key: ${{ steps.date.outputs.date }}_${{ inputs.pixi-version }}_${{hashFiles('pixi.toml')}}
+          key: ${{ steps.date.outputs.date }}_${{ inputs.pixi-version }}_${{hashFiles('pixi.toml', 'pyproject.toml')}}
       - uses: prefix-dev/[email protected]
         if: ${{ !steps.restore.outputs.cache-hit }}
         with:

doc/whats-new.rst

@@ -27,6 +27,12 @@ New Features
   brings improved alignment between h5netcdf and libnetcdf4 in the storage of
   complex numbers (:pull:`11068`). By `Mark Harfouche
   <https://github.com/hmaarrfk>`_.
+- Added typed properties for external accessor packages (hvplot, cf-xarray,
+  pint-xarray, rioxarray, xarray-plotly), enabling full IDE support including
+  autocompletion, parameter hints, and docstrings. For uninstalled packages,
+  ``hasattr()`` returns ``False`` to keep the namespace clean (:pull:`11079`).
+  By `Your Name <https://github.com/FBumann>`_.
+
 - :py:func:`set_options` now supports an ``arithmetic_compat`` option which determines how non-index coordinates
   of the same name are compared for potential conflicts when performing binary operations. The default for it is
   ``arithmetic_compat='minimal'`` which matches the existing behaviour.

pyproject.toml

@@ -138,6 +138,7 @@ module = [
   "bottleneck.*",
   "cartopy.*",
   "cf_units.*",
+  "cf_xarray.*",
   "cfgrib.*",
   "cftime.*",
   "cloudpickle.*",
@@ -146,6 +147,7 @@ module = [
   "fsspec.*",
   "h5netcdf.*",
   "h5py.*",
+  "hvplot.*",
   "iris.*",
   "mpl_toolkits.*",
   "nc_time_axis.*",
@@ -154,14 +156,17 @@ module = [
   "numcodecs.*",
   "opt_einsum.*",
   "pint.*",
+  "pint_xarray.*",
   "pooch.*",
   "pyarrow.*",
   "pydap.*",
+  "rioxarray.*",
   "scipy.*",
   "seaborn.*",
   "setuptools",
   "sparse.*",
   "toolz.*",
+  "xarray_plotly.*",
   "zarr.*",
   "numpy.exceptions.*", # remove once support for `numpy<2.0` has been dropped
   "array_api_strict.*",

xarray/accessors.py

@@ -0,0 +1,53 @@
+"""
+External accessor support for xarray.
+
+This module provides mixin classes with typed properties for external accessor
+packages, enabling full IDE support (autocompletion, parameter hints, docstrings)
+for packages like hvplot, cf-xarray, pint-xarray, rioxarray, and xarray-plotly.
+
+Properties are defined statically for IDE support
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, ClassVar
+
+if TYPE_CHECKING:
+    from cf_xarray.accessor import CFAccessor
+    from hvplot.xarray import hvPlotAccessor
+    from pint_xarray import PintDataArrayAccessor, PintDatasetAccessor
+    from rioxarray import RasterArray, RasterDataset
+    from xarray_plotly import DataArrayPlotlyAccessor, DatasetPlotlyAccessor
+
+
+class DataArrayExternalAccessorMixin:
+    """Mixin providing typed external accessor properties for DataArray."""
+
+    __slots__ = ()
+
+    hvplot: ClassVar[type[hvPlotAccessor]]
+    cf: ClassVar[type[CFAccessor]]
+    pint: ClassVar[type[PintDataArrayAccessor]]
+    rio: ClassVar[type[RasterArray]]
+    plotly: ClassVar[type[DataArrayPlotlyAccessor]]
+
+
+class DatasetExternalAccessorMixin:
+    """Mixin providing typed external accessor properties for Dataset."""
+
+    __slots__ = ()
+
+    hvplot: ClassVar[type[hvPlotAccessor]]
+    cf: ClassVar[type[CFAccessor]]
+    pint: ClassVar[type[PintDatasetAccessor]]
+    rio: ClassVar[type[RasterDataset]]
+    plotly: ClassVar[type[DatasetPlotlyAccessor]]
+
+
+class DataTreeExternalAccessorMixin:
+    """Mixin providing typed external accessor properties for DataTree."""
+
+    __slots__ = ()
+
+    hvplot: ClassVar[type[hvPlotAccessor]]
+    cf: ClassVar[type[CFAccessor]]

xarray/core/dataarray.py

@@ -19,6 +19,7 @@
 import numpy as np
 import pandas as pd
 
+from xarray.accessors import DataArrayExternalAccessorMixin
 from xarray.coding.calendar_ops import convert_calendar, interp_calendar
 from xarray.coding.cftimeindex import CFTimeIndex
 from xarray.computation import computation, ops
@@ -259,6 +260,7 @@ class DataArray(
     DataWithCoords,
     DataArrayArithmetic,
     DataArrayAggregations,
+    DataArrayExternalAccessorMixin,
 ):
     """N-dimensional array with labeled coordinates and dimensions.
 

xarray/core/dataset.py

@@ -29,6 +29,7 @@
 import numpy as np
 import pandas as pd
 
+from xarray.accessors import DatasetExternalAccessorMixin
 from xarray.coding.calendar_ops import convert_calendar, interp_calendar
 from xarray.coding.cftimeindex import CFTimeIndex, _parse_array_of_cftime_strings
 from xarray.compat.array_api_compat import to_like_array
@@ -197,6 +198,7 @@ class Dataset(
     DataWithCoords,
     DatasetAggregations,
     DatasetArithmetic,
+    DatasetExternalAccessorMixin,
     Mapping[Hashable, "DataArray"],
 ):
     """A multi-dimensional, in memory, array database.

xarray/core/datatree.py

@@ -28,6 +28,7 @@
     overload,
 )
 
+from xarray.accessors import DataTreeExternalAccessorMixin
 from xarray.core import utils
 from xarray.core._aggregations import DataTreeAggregations
 from xarray.core._typed_ops import DataTreeOpsMixin
@@ -464,6 +465,7 @@ class DataTree(
     DataTreeAggregations,
     DataTreeOpsMixin,
     TreeAttrAccessMixin,
+    DataTreeExternalAccessorMixin,
     Mapping[str, "DataArray | DataTree"],
 ):
     """