ModuleNotFoundError: No module named 'packaging' starting with 1.0.2 #237
Description
Since version 1.0.2, if pandas is installed, patsy should require packaging to be installed too because it now runs import packaging.version with no try/except around it.
Reproduction
❯ python3.10 -m venv venv
❯ source venv/bin/activate
❯ pip install patsy pandas
[...]
Successfully installed numpy-2.2.6 pandas-2.3.3 patsy-1.0.2 python-dateutil-2.9.0.post0 pytz-2025.2 six-1.17.0 tzdata-2025.2
[notice] A new release of pip is available: 23.0.1 -> 25.2
[notice] To update, run: pip install --upgrade pip
❯ python -c "import patsy"
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "venv/lib/python3.10/site-packages/patsy/__init__.py", line 87, in <module>
import patsy.highlevel
File "venv/lib/python3.10/site-packages/patsy/highlevel.py", line 18, in <module>
from patsy.design_info import DesignMatrix, DesignInfo
File "venv/lib/python3.10/site-packages/patsy/design_info.py", line 28, in <module>
from patsy.util import atleast_2d_column_default
File "venv/lib/python3.10/site-packages/patsy/util.py", line 46, in <module>
import packaging.version
ModuleNotFoundError: No module named 'packaging'Introduced in efa450f#diff-7824b5b016cfbc41ef1ae2359d3e8f72bb84840518a6074430a2a9a7a04110adR46-R57
Workaround
No such issue without pandas nor with patsy<1.0.2 as expected.