deprecate cftime_range() in favor of date_range(use_cftime=True) (#10024)

Co-authored-by: Maximilian Roos <[email protected]>
Co-authored-by: Kai Mühlbauer <[email protected]>
Co-authored-by: Spencer Clark <[email protected]>
Co-authored-by: maddogghoek <maddogghoek@penguin>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 6 people

Diff for: doc/contributing.rst

@@ -580,9 +580,9 @@ a user passes ``old_arg``, we would instead catch it:
 
     def func(new_arg, old_arg=None):
         if old_arg is not None:
-            from warnings import warn
+            from xarray.core.utils import emit_user_level_warning
 
-            warn(
+            emit_user_level_warning(
                 "`old_arg` has been deprecated, and in the future will raise an error."
                 "Please use `new_arg` from now on.",
                 DeprecationWarning,

Diff for: doc/user-guide/weather-climate.rst

@@ -98,13 +98,18 @@ coordinate with dates from a no-leap calendar and a
     ]
     da = xr.DataArray(np.arange(24), coords=[dates], dims=["time"], name="foo")
 
-Xarray also includes a :py:func:`~xarray.cftime_range` function, which enables
+Xarray also includes a :py:func:`~xarray.date_range` function, which enables
 creating a :py:class:`~xarray.CFTimeIndex` with regularly-spaced dates.  For
-instance, we can create the same dates and DataArray we created above using:
+instance, we can create the same dates and DataArray we created above using
+(note that ``use_cftime=True`` is not mandatory to return a
+:py:class:`~xarray.CFTimeIndex` for non-standard calendars, but can be nice
+to use to be explicit):
 
 .. ipython:: python
 
-    dates = xr.cftime_range(start="0001", periods=24, freq="MS", calendar="noleap")
+    dates = xr.date_range(
+        start="0001", periods=24, freq="MS", calendar="noleap", use_cftime=True
+    )
     da = xr.DataArray(np.arange(24), coords=[dates], dims=["time"], name="foo")
 
 Mirroring pandas' method with the same name, :py:meth:`~xarray.infer_freq` allows one to
@@ -138,7 +143,9 @@ use ``pandas`` when possible, i.e. when the calendar is ``standard``/``gregorian
 
 .. ipython:: python
 
-    dates = xr.cftime_range(start="2001", periods=24, freq="MS", calendar="noleap")
+    dates = xr.date_range(
+        start="2001", periods=24, freq="MS", calendar="noleap", use_cftime=True
+    )
     da_nl = xr.DataArray(np.arange(24), coords=[dates], dims=["time"], name="foo")
     da_std = da.convert_calendar("standard", use_cftime=True)
 

Diff for: doc/whats-new.rst

@@ -38,6 +38,9 @@ Breaking changes
 
 Deprecations
 ~~~~~~~~~~~~
+- Deprecate :py:func:`~xarray.cftime_range` in favor of :py:func:`~xarray.date_range` with ``use_cftime=True``
+  (:issue:`9886`, :pull:`10024`).
+  By `Josh Kihm <https://github.com/maddogghoek>`_.
 - Move from phony_dims=None to phony_dims="access" for h5netcdf-backend(:issue:`10049`, :pull:`10058`)
   By `Kai Mühlbauer <https://github.com/kmuehlbauer>`_.