pandas 0.21.0 Timestamp compatibility issue with matplotlib

Question

I just updated pandas from 0.17.1 to 0.21.0 to take advantage of some new functionalities, and ran into compatibility issue with matplotlib (which I also updated to latest 2

Answer 1

After opening an issue on pandas github, I learned that this was indeed a known issue between pandas and matplotlib regarding auto-registration of unit converter. In fact it was listed on what's new page which I had failed to see before, along with the proper way to register the converters:

from pandas.tseries import converter
converter.register() 

This is also done the first time a member plot method is called on a Series or DataFrame which explains what I observed above.

It appears to have been done with the intention that matplotlib is supposed to implement some basic support for pandas datetime, but indeed a deprecation warning of some sort could be useful for such a break. However until matplotlib actually implements such support (or some sort of lazy registration mechanism), practically I'm always putting those two lines at the pandas import. So I'm not sure why pandas would want to disable the automatic registration on import before things are ready on the matplotlib side.