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[Bug]: matplotlib simple example fails in Python 3.14 #30370
Description
Bug summary
Using the simplest Pyplot example as a minimal test case on Python 3.14 gives a RecursionError: maximum recursion depth exceeded in path.py.
Code for reproduction
import matplotlib.pyplot as plt
plt.plot([1, 2, 3, 4])
plt.ylabel('some numbers')
plt.show()Actual outcome
... trails way back ...
File "/home/bje/source/nemo/myenv/lib/python3.14/site-packages/matplotlib/path.py", line 285, in __deepcopy__
p = copy.deepcopy(super(), memo)
File "/usr/lib/python3.14/copy.py", line 157, in deepcopy
y = _reconstruct(x, memo, *rv)
File "/usr/lib/python3.14/copy.py", line 234, in _reconstruct
y = func(*args)
File "/usr/lib/python3.14/copy.py", line 233, in <genexpr>
args = (deepcopy(arg, memo) for arg in args)
~~~~~~~~^^^^^^^^^^^
File "/usr/lib/python3.14/copy.py", line 138, in deepcopy
y = copier(memo)
File "/home/bje/source/nemo/myenv/lib/python3.14/site-packages/matplotlib/path.py", line 285, in __deepcopy__
p = copy.deepcopy(super(), memo)
RecursionError: maximum recursion depth exceededExpected outcome
The simple example should Just Work.
Additional information
No response
Operating system
Ubuntu 24.04
Matplotlib Version
3.10.3
Matplotlib Backend
WxAgg
Python version
Python 3.14.0rc1
Jupyter version
No response
Installation
pip
Activity
story645 commentedon Jul 30, 2025
I think this is supposed to be fixed by #30198, which should be in the next release (which is in the works so should be out soon(ish)).
bje- commentedon Jul 30, 2025
Yes, thanks, I see it's fixed in the nightly build.