adjust the deprecation policy for python (#7793)

* extend the policy interval for python to 30 months

* extend the hard-coded list of python release dates

* changelog

Author: keewis

ci/min_deps_check.py

@@ -29,7 +29,7 @@
     "pytest-timeout",
 }
 
-POLICY_MONTHS = {"python": 24, "numpy": 18}
+POLICY_MONTHS = {"python": 30, "numpy": 18}
 POLICY_MONTHS_DEFAULT = 12
 POLICY_OVERRIDE: dict[str, tuple[int, int]] = {}
 errors = []
@@ -109,6 +109,9 @@ def metadata(entry):
                 (3, 6): datetime(2016, 12, 23),
                 (3, 7): datetime(2018, 6, 27),
                 (3, 8): datetime(2019, 10, 14),
+                (3, 9): datetime(2020, 10, 5),
+                (3, 10): datetime(2021, 10, 4),
+                (3, 11): datetime(2022, 10, 24),
             }
         )
 

doc/getting-started-guide/installing.rst

@@ -86,7 +86,7 @@ Minimum dependency versions
 Xarray adopts a rolling policy regarding the minimum supported version of its
 dependencies:
 
-- **Python:** 24 months
+- **Python:** 30 months
   (`NEP-29 <https://numpy.org/neps/nep-0029-deprecation_policy.html>`_)
 - **numpy:** 18 months
   (`NEP-29 <https://numpy.org/neps/nep-0029-deprecation_policy.html>`_)

doc/whats-new.rst

@@ -31,7 +31,8 @@ New Features
 
 Breaking changes
 ~~~~~~~~~~~~~~~~
-
+- adjust the deprecation policy for python to once again align with NEP-29 (:issue:`7765`, :pull:`7793`)
+  By `Justus Magin <https://github.com/keewis>`_.
 
 Deprecations
 ~~~~~~~~~~~~