ensure removal of font cache on version upgrade

[ghost]

I just re-installed matplotlib on Linux VERSION="14.04.1 LTS, Trusty Tahr". Importing matplotlib suddendly became really slow, ~3 seconds. Reason being afm.py. (details at: http://stackoverflow.com/questions/26421364/extremely-slow-import-of-matplotlib-afm).

Matplotlib version is 1.4.0.

[jenshnielsen]

I think this is related to the generation of font cache. This should normally only happen at the first import of matplotlib unless you delete 'fontList.cache' in your matplotlib configuration dir i.e. probably ~/.matplotlib

[tacaswell]

I can't reproduce this, even if I delete my font cache.

[g2p]

I had this problem, with time python -c 'import matplotlib.font_manager' taking at least five seconds. I had some broken .afm files and fontList.cache was never generated; I had to add a print statement to find which files were involved, because the files are all opened before any parsing begins.

[naskomit]

I had the same problem. I figured out, that this happens when you upgrade matplotlib to a newer version. The cache file is not compatible with the new version, but apparently is not recreated. Instead font list is created each time on the fly. The solution is to delete the matplotlib cache directory (in my case ~/.cache/matplotlib

[Zaharid]

I can confirm this. I was able to resolve the problem by removing the matplotlib cache, as suggested here:

http://stackoverflow.com/questions/26421364/extremely-slow-import-of-matplotlib-afm

[wxgeo]

Same issue for me (matplotlib 1.4.2 on Ubuntu 15.10), and removing matplotlib cache works well too.

rm -r ~/.cache/matplotlib/

Thanks for the tip, importing matplotlib was so painfully slow !