# swegym / pandas-dev__pandas-53736 - taskset: [swegym](https://harnessreport.com/tasks/swegym.md) - difficulty: hard - category: debugging - language: - runnable from the site: no - agent timeout: 3000s ## Results by harness _none yet_ ## Instruction ``` BUG: resampling empty series loses time zone from dtype ### Pandas version checks - [X] I have checked that this issue has not already been reported. - [X] I have confirmed this bug exists on the [latest version](https://pandas.pydata.org/docs/whatsnew/index.html) of pandas. - [ ] I have confirmed this bug exists on the [main branch](https://pandas.pydata.org/docs/dev/getting_started/install.html#installing-the-development-version-of-pandas) of pandas. ### Reproducible Example ```python df = pd.DataFrame({ 'ts': [], 'values': [] }).astype({'ts': 'datetime64[ns, Atlantic/Faroe]'}) df.resample('2MS', on='ts', closed='left', label='left', origin='start')['values'].sum().index ``` ### Issue Description this prints ```python DatetimeIndex([], dtype='datetime64[ns]', name='ts', freq='2MS') ``` ### Expected Behavior ``` DatetimeIndex([], dtype='datetime64[ns, Atlantic/Faroe]', name='ts', freq='2MS') ``` note that this works fine if the series isn't empty ```python In [27]: df = pd.DataFrame({ ...: 'ts': [datetime(2020, 1, 1)], ...: 'values': [10] ...: }) ...: df['ts'] = df['ts'].dt.tz_localize('Atlantic/Faroe') ...: df.resample('2MS', on='ts', closed='left', label='left', origin='start')['values'].sum().index Out[27]: DatetimeIndex(['2020-01-01 00:00:00+00:00'], dtype='datetime64[ns, Atlantic/Faroe]', name='ts', freq='2MS') ``` ### Installed Versions <details> INSTALLED VERSIONS ------------------ commit : 965ceca9fd796940050d6fc817707bba1c4f9bff python : 3.10.6.final.0 python-bits : 64 OS : Linux OS-release : 5.10.102.1-microsoft-standard-WSL2 Version : #1 SMP Wed Mar 2 00:30:59 UTC 2022 machine : x86_64 processor : x86_64 byteorder : little LC_ALL : None LANG : en_GB.UTF-8 LOCALE : en_GB.UTF-8 pandas : 2.0.2 numpy : 1.24.3 pytz : 2023.3 dateutil : 2.8.2 setuptools : 67.6.1 pip : 23.0.1 Cython : None pytest : 7.3.1 hypothesis : None sphinx : None blosc : None feather : None xlsxwriter : None lxml.etree : None html5lib : None pymysql : None psycopg2 : None jinja2 : 3.1.2 IPython : 8.13.2 pandas_datareader: None bs4 : 4.12.2 bottleneck : None brotli : None fastparquet : None fsspec : None gcsfs : None matplotlib : 3.7.1 numba : None numexpr : None odfpy : None openpyxl : None pandas_gbq : None pyarrow : 12.0.0 pyreadstat : None pyxlsb : None s3fs : None scipy : None snappy : None sqlalchemy : None tables : None tabulate : None xarray : None xlrd : None zstandard : None tzdata : 2023.3 qtpy : None pyqt5 : None </details> ``` --- Harness Report runs agent harnesses from their GitHub repos on Harbor tasks and records every model call. Every page is also `.md` and `.json`; index: https://harnessreport.com/llms.txt · MCP: https://harnessreport.com/mcp