BUG: freq after sort values differs between arm Mac and ubuntu

[phofl]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

pdf = pd.DataFrame({"z": 1})
pdf.z.sort_values()


2020-12-31    1
2021-01-01    1
2021-01-02    1
2021-01-03    1
2021-01-04    1
             ..
2021-04-05    1
2021-04-06    1
2021-04-07    1
2021-04-08    1
2021-04-09    1
Freq: D, Name: z, Length: 100, dtype: int64

Issue Description

This preserves the freq on ubuntu but loses it on Mac

Expected Behavior

don't know, consistency above everything else

I can't test the nightlies on ubuntu right now, that's why it's only 2.2.2

Installed Versions

INSTALLED VERSIONS

commit : d9cdd2e
python : 3.12.4.final.0
python-bits : 64
OS : Darwin
OS-release : 23.3.0
Version : Darwin Kernel Version 23.3.0: Wed Dec 20 21:33:31 PST 2023; root:xnu-10002.81.5~7/RELEASE_ARM64_T8112
machine : arm64
processor : arm
byteorder : little
LC_ALL : None
LANG : None
LOCALE : None.UTF-8

pandas : 2.2.2
numpy : 2.0.0
pytz : 2024.1
dateutil : 2.9.0
setuptools : 70.1.0
pip : 24.0
Cython : None
pytest : 8.2.2
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.1.4
IPython : 8.25.0
pandas_datareader : None
adbc-driver-postgresql: None
adbc-driver-sqlite : None
bs4 : 4.12.3
bottleneck : None
dataframe-api-compat : None
fastparquet : None
fsspec : 2024.6.0
gcsfs : None
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : 16.1.0
pyreadstat : None
python-calamine : None
pyxlsb : None
s3fs : 2024.6.0
scipy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : 2024.6.0
xlrd : None
zstandard : None
tzdata : 2024.1
qtpy : None
pyqt5 : None
None

[phofl]

cc @jbrockmendel thoughts here?

[jbrockmendel]

I don't have an ubuntu env ATM, so speculating: sort_values go through nargsort which I suspect may have undefined behavior in non-unique cases.

BTW the example in the OP is not reproducible, needs an index passed to DataFrame.