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Description
Bug summary
Creating an empty FancyArrow throws an exception:
>>> import matplotlib.pyplot as plt
>>> plt.arrow([], [], [], [])
matplotlib/axes/_axes.py", line 5509, in arrow
a = mpatches.FancyArrow(x, y, dx, dy, **kwargs)
matplotlib/patches.py", line 1459, in __init__
self._make_verts()
matplotlib/patches.py", line 1518, in _make_verts
if not length:
^^^^^^
ValueError: The truth value of an empty array is ambiguous. Use `array.size > 0` to check that an array is not empty.
That exception used to throw a numpy deprecation warning, but that deprecation has recently expired and now throws an exception.
That section appears to intend to properly handle zero-length input (matplotlib/patches.py", line 1518),
if not length:
self.verts = np.empty([0, 2]) # display nothing if emptyThe fix appears to be to change the if not length to if length.size == 0.
Code for reproduction
import matplotlib.pyplot as plt
plt.arrow([], [], [], [])Actual outcome
matplotlib/axes/_axes.py", line 5509, in arrow
a = mpatches.FancyArrow(x, y, dx, dy, **kwargs)
matplotlib/patches.py", line 1459, in __init__
self._make_verts()
matplotlib/patches.py", line 1518, in _make_verts
if not length:
^^^^^^
ValueError: The truth value of an empty array is ambiguous. Use `array.size > 0` to check that an array is not empty.
Expected outcome
Return a valid FancyArrow
Additional information
python version 3.12
matplotlib version: 3.10.3 (latest release)
numpy version: 2.2.6 (deprecation above expired in 2.2.0, released Dec 2024)
Operating system
No response
Matplotlib Version
3.10.3
Matplotlib Backend
No response
Python version
3.12.8
Jupyter version
No response
Installation
pip
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