mpl_connect silently does nothing when passed an invalid event type string

[dstansby]

Bug report

If fig.canvas.mpl_connect is passed an invalid event type string, it silently does nothing. I think there should at least be a warning (maybe an error?)

Code for reproduction

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
def onclick(event):
    print('Event!')
cid = fig.canvas.mpl_connect('invalid_event_string', onclick)
plt.show()

Actual outcome

Clicking around or doing or trying to trigger onclick() does nothing.

Expected outcome

I would expect a warning if 'invalid_event_string' isn't one of the strings listed at http://matplotlib.org/devdocs/api/backend_bases_api.html?highlight=mpl_connect#matplotlib.backend_bases.FigureCanvasBase.mpl_connect

Matplotlib version

• Matplotlib Version: master installed from source using pip

[WeatherGod]

Adding a warning might be noisier than useful as events get connected and disconnected all the time. We should see if we are regularly firing events after disconnects or not. But I can see how this could be useful for debugging.

…

On Jul 4, 2017 11:32 AM, "David Stansby" ***@***.***> wrote: Bug report If fig.canvas.mpl_connect is passed an invalid event type string, it silently does nothing. I think there should at least be a warning (maybe an error?) *Code for reproduction* import matplotlib.pyplot as plt fig, ax = plt.subplots()def onclick(event): print('Event!') cid = fig.canvas.mpl_connect('invalid_event_string', onclick) plt.show() *Actual outcome* Clicking around or doing or trying to trigger onclick() does nothing. *Expected outcome* I would expect a warning if 'invalid_event_string' isn't one of the strings listed at http://matplotlib.org/devdocs/ api/backend_bases_api.html?highlight=mpl_connect#matplotlib.backend_bases. FigureCanvasBase.mpl_connect *Matplotlib version* - Matplotlib Version: master installed from source using pip — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#8839>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AARy-JNEYD1iLc19seb4BxF2Op2fEgu_ks5sKlsMgaJpZM4ONfXo> .

[tacaswell]

The callback registries do not know what keys they are going to get (which I think is a feature!), but adding an optional set of expected keys to the registry init + warning or error on invalid keys is a reasonable idea.

[WeatherGod]

No, I was thinking more along the lines of issuing a warning for unknown events on the emit call. Although, now that I think of it, that wouldn't help for connecting to built-in events.

…

On Jul 5, 2017 4:03 PM, "Thomas A Caswell" ***@***.***> wrote: The callback registries do not know what keys they are going to get (which I think is a feature!), but adding an optional set of expected keys to the registry init + warning or error on invalid keys is a reasonable idea. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#8839 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AARy-HgcXt7ANz0Pgj2RSB75Q-EQMJnmks5sK-wkgaJpZM4ONfXo> .