BUG: UnboundLocalError when calling pd.option_context with an invalid key on the main branch #62724
Description
Pandas version checks
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I have checked that this issue has not already been reported.
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I have confirmed this bug exists on the latest version of pandas.
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I have confirmed this bug exists on the main branch of pandas.
Reproducible Example
import pandas as pd with pd.option_context("invalid", True): passIssue Description
Traceback (most recent call last): File ~/miniforge3/envs/dev/lib/python3.13/site-packages/pandas/_config/config.py:507 in option_context undo = tuple((pat, get_option(pat)) for pat, val in ops) File ~/miniforge3/envs/dev/lib/python3.13/site-packages/pandas/_config/config.py:507 in <genexpr> undo = tuple((pat, get_option(pat)) for pat, val in ops) File ~/miniforge3/envs/dev/lib/python3.13/site-packages/pandas/_config/config.py:185 in get_option key = _get_single_key(pat) File ~/miniforge3/envs/dev/lib/python3.13/site-packages/pandas/_config/config.py:129 in _get_single_key raise OptionError(f"No such keys(s): {pat!r}") OptionError: No such keys(s): 'invalid' During handling of the above exception, another exception occurred: Traceback (most recent call last): Cell In[3], line 1 with pd.option_context("invalid", True): File ~/miniforge3/envs/dev/lib/python3.13/contextlib.py:141 in __enter__ return next(self.gen) File ~/miniforge3/envs/dev/lib/python3.13/site-packages/pandas/_config/config.py:512 in option_context for pat, val in undo: UnboundLocalError: cannot access local variable 'undo' where it is not associated with a valueExpected Behavior
In the latest stable release (2.3.3) one would get an OptionError instead:
Traceback (most recent call last): Cell In[3], line 1 with pd.option_context("invalid", True): File ~/miniforge3/envs/tmp/lib/python3.14/site-packages/pandas/_config/config.py:480 in __enter__ self.undo = [(pat, _get_option(pat)) for pat, val in self.ops] File ~/miniforge3/envs/tmp/lib/python3.14/site-packages/pandas/_config/config.py:146 in _get_option key = _get_single_key(pat, silent) File ~/miniforge3/envs/tmp/lib/python3.14/site-packages/pandas/_config/config.py:132 in _get_single_key raise OptionError(f"No such keys(s): {repr(pat)}") OptionError: "No such keys(s): 'invalid'"Installed Versions
INSTALLED VERSIONS
commit : 531c0e3
python : 3.13.7
python-bits : 64
OS : Darwin
OS-release : 24.6.0
Version : Darwin Kernel Version 24.6.0: Mon Jul 14 11:30:40 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T8132
machine : arm64
processor : arm
byteorder : little
LC_ALL : None
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8
pandas : 3.0.0.dev0+2551.g531c0e3689
numpy : 2.3.3
dateutil : 2.9.0.post0
pip : 25.2
Cython : 3.1.4
sphinx : None
IPython : 9.6.0
adbc-driver-postgresql: None
adbc-driver-sqlite : None
bs4 : 4.14.2
bottleneck : None
fastparquet : None
fsspec : None
html5lib : None
hypothesis : None
gcsfs : None
jinja2 : 3.1.6
lxml.etree : None
matplotlib : 3.10.6
numba : None
numexpr : None
odfpy : None
openpyxl : None
psycopg2 : None
pymysql : None
pyarrow : None
pyiceberg : None
pyreadstat : None
pytest : 8.4.2
python-calamine : None
pytz : 2025.2
pyxlsb : None
s3fs : None
scipy : 1.16.2
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlsxwriter : None
zstandard : 0.25.0
qtpy : None
pyqt5 : None