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Description
Bug summary
I've got a class Charts that uses self.fig.canvas.mpl_connect('key_press_event', self.sendEvent) to handle keypresses, which works fine. But recently I tried changing my class to subclass dict, and – oddly – this seems to confuse Matplotlib. I get the error:
File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/helipad/visualize.py", line 72, in launch
self.fig.canvas.mpl_connect('key_press_event', self.sendEvent)
File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/matplotlib/backend_bases.py", line 2476, in mpl_connect
return self.callbacks.connect(s, func)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/matplotlib/cbook/__init__.py", line 228, in connect
if proxy in self._func_cid_map[signal]:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: unhashable type: 'Charts'
Which is weird because I'm not passing Charts at all.
Looking at MPL's code, it looks like the _weak_or_strong_ref function is getting a reference to Charts back out of the method I passed as a callback, putting it in the proxy variable, and hashing it, which subclassing dict prevents it from doing.
Code for reproduction
import matplotlib.pyplot as plt
class ThisWorks:
def __init__(self):
self.fig, plots = plt.subplots(1)
self.fig.canvas.mpl_connect('key_press_event', self.sendEvent)
self.keyListeners = {}
def sendEvent(self, event):
if event.name=='key_press_event' and event.key in self.keyListeners:
for f in self.keyListeners[event.key]: f(self.model, event)
class ThisDoesntWork(ThisWorks, dict): pass
x = ThisDoesntWork()Actual outcome
Traceback (most recent call last):
File "/Users/charwick/Desktop/example.py", line 15, in <module>
x = ThisDoesntWork()
^^^^^^^^^^^^^^^^
File "example.py", line 6, in __init__
self.fig.canvas.mpl_connect('key_press_event', self.sendEvent)
File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/matplotlib/backend_bases.py", line 2476, in mpl_connect
return self.callbacks.connect(s, func)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/matplotlib/cbook/__init__.py", line 227, in connect
if proxy in self._func_cid_map[signal]:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: unhashable type: 'ThisDoesntWork'
Expected outcome
Code above doesn't actually do anything, but it shouldn't generate an error.
Additional information
No response
Operating system
MacOS 13.3.1
Matplotlib Version
3.7.1
Matplotlib Backend
No response
Python version
3.11.3
Jupyter version
No response
Installation
pip
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