BUG: matplotlib 3.4.0 -- Scatter with colormap and legend gives TypeError: object of type 'NoneType' has no len() #19779
Description
Bug report
Bug summary
With matplotlib 3.4.0, scatter plot with colormap and legend gives TypeError: object of type 'NoneType' has no len().
Code for reproduction
import matplotlib.pyplot as plt
y = [1, 2, 3, 4, 5]
plt.scatter(y, y, label='Y', lw=0, s=8, c=y, cmap='viridis')
plt.legend()
plt.show()Actual outcome
Traceback (most recent call last):
File ".../matplotlib/backends/backend_qt5.py", line 475, in _draw_idle
self.draw()
File ".../matplotlib/backends/backend_agg.py", line 406, in draw
self.figure.draw(self.renderer)
File ".../matplotlib/artist.py", line 74, in draw_wrapper
result = draw(artist, renderer, *args, **kwargs)
File ".../matplotlib/artist.py", line 51, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File ".../matplotlib/figure.py", line 2734, in draw
mimage._draw_list_compositing_images(
File ".../matplotlib/image.py", line 132, in _draw_list_compositing_images
a.draw(renderer)
File ".../matplotlib/artist.py", line 51, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File ".../matplotlib/_api/deprecation.py", line 431, in wrapper
return func(*inner_args, **inner_kwargs)
File ".../matplotlib/axes/_base.py", line 2925, in draw
mimage._draw_list_compositing_images(renderer, self, artists)
File ".../matplotlib/image.py", line 132, in _draw_list_compositing_images
a.draw(renderer)
File ".../matplotlib/artist.py", line 51, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File ".../matplotlib/legend.py", line 614, in draw
self._legend_box.draw(renderer)
File ".../matplotlib/offsetbox.py", line 368, in draw
c.draw(renderer)
File ".../matplotlib/offsetbox.py", line 368, in draw
c.draw(renderer)
File ".../matplotlib/offsetbox.py", line 368, in draw
c.draw(renderer)
[Previous line repeated 1 more time]
File ".../matplotlib/offsetbox.py", line 694, in draw
c.draw(renderer)
File ".../matplotlib/artist.py", line 51, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File ".../matplotlib/collections.py", line 1009, in draw
super().draw(renderer)
File ".../matplotlib/artist.py", line 51, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File ".../matplotlib/collections.py", line 380, in draw
len(facecolors) == 1 and len(edgecolors) == 1 and
TypeError: object of type 'NoneType' has no len()
Expected outcome
With matplotlib 3.3.4, I get this (no warning or error):
Matplotlib version
- Operating system: Red Hat Enterprise Linux Server release 7.9 (Maipo)
- Matplotlib version (
import matplotlib; print(matplotlib.__version__)): 3.4.0 - Matplotlib backend (
print(matplotlib.get_backend())): Qt5Agg - Python version: 3.8.3
- Jupyter version (if applicable): N/A
- Other libraries: Not sure what else you need, just let me know.