gnu: python-pandas-2: Fix test with new tzdata.

Fixes: guix/guix#1025

* gnu/packages/patches/python-pandas-2-no-pytz_datetime.patch: New patch.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/python-science.scm (python-pandas-2): Use it.

Change-Id: I0e3689c28f11a5f69362caf0e31890a5efe6febe
Signed-off-by: Andreas Enge <andreas@enge.fr>

gnu/local.mk

@@ -2173,6 +2173,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/python-memcached-syntax-warnings.patch	\
   %D%/packages/patches/python-mox3-python3.6-compat.patch	\
   %D%/packages/patches/python-packaging-test-arch.patch		\
+  %D%/packages/patches/python-pandas-2-no-pytz_datetime.patch		\
   %D%/packages/patches/python-property-cached-asyncio-3_11.patch	\
   %D%/packages/patches/python-pyan3-fix-absolute-path-bug.patch \
   %D%/packages/patches/python-pyan3-fix-positional-arguments.patch \

gnu/packages/patches/python-pandas-2-no-pytz_datetime.patch

@@ -0,0 +1,47 @@
+from https://salsa.debian.org/science-team/pandas/-/raw/main/debian/patches/no_pytz_datetime.patch
+
+Description: datetime does not work with non-constant pytz.timezone
+
+This has always been the case (and is explicitly warned about
+in the pytz documentation), but became a test fail when
+tzdata 2024b changed 'CET' and similar to aliases.
+
+Author: Rebecca N. Palmer <rebecca_palmer@zoho.com>
+Forwarded: no
+
+--- a/pandas/tests/arrays/test_array.py
++++ b/pandas/tests/arrays/test_array.py
+@@ -272,7 +272,8 @@ def test_array_copy():
+     assert tm.shares_memory(a, b)
+
+ 
+-cet = pytz.timezone("CET")
++cetfixed = pytz.timezone("Etc/GMT-1") # the wrong-looking sign is because Etc/* use posix convention, as described in the tzdata source
++cetwithdst = pytz.timezone("Europe/Brussels")
+
+ 
+ @pytest.mark.parametrize(
+@@ -313,11 +314,20 @@ cet = pytz.timezone("CET")
+         ),
+         (
+             [
+-                datetime.datetime(2000, 1, 1, tzinfo=cet),
+-                datetime.datetime(2001, 1, 1, tzinfo=cet),
++                datetime.datetime(2000, 1, 1, tzinfo=cetfixed),
++                datetime.datetime(2001, 1, 1, tzinfo=cetfixed),
+             ],
+             DatetimeArray._from_sequence(
+-                ["2000", "2001"], dtype=pd.DatetimeTZDtype(tz=cet, unit="ns")
++                ["2000", "2001"], dtype=pd.DatetimeTZDtype(tz=cetfixed, unit="ns")
++            ),
++        ),
++        (
++            [
++                cetwithdst.localize(datetime.datetime(2000, 1, 1)),
++                cetwithdst.localize(datetime.datetime(2001, 1, 1)),
++            ],
++            DatetimeArray._from_sequence(
++                ["2000", "2001"], dtype=pd.DatetimeTZDtype(tz=cetwithdst, unit="ns")
+             ),
+         ),
+         # timedelta

gnu/packages/python-science.scm

@@ -3167,7 +3167,8 @@ doing practical, real world data analysis in Python.")
              (commit (string-append "v" version))))
        (file-name (git-file-name name version))
        (sha256
-        (base32 "00f6jnplwg7iffnxdm4hpfls0ncbarc23933xq1rm5nk5g8dcldx"))))
+        (base32 "00f6jnplwg7iffnxdm4hpfls0ncbarc23933xq1rm5nk5g8dcldx"))
+       (patches (search-patches "python-pandas-2-no-pytz_datetime.patch"))))
     (build-system pyproject-build-system)
     (arguments
      (list