Histogram visualizer breaks when histogram does not have x_min and x_max information

[vicha-w]

Hi,

MLP frontend redesign has been live for a few hours, but I already noticed a bug on the visualizer with the following error log:

TypeError at /visualize/316218/941/num_clusters_ontrack_PXBarrel/
unsupported operand type(s) for +: 'NoneType' and 'int'

This error is caused by some histograms not having x_bin attribute. This attribute is required in this line: https://github.com/CMSTrackerDPG/MLplayground/blob/master/visualize_histogram/views.py#L62 Furthermore, those histograms also do not have x_min and x_max attributes, which is required in the plotting as well. I have checked the DB in production, and found that these histograms amount to 268 136 out of 447 754 1D histograms, more than half of the histograms in 1D lumisection database.

For the reference, here is an example link that breaks the backend: https://ml4dqm-playground.web.cern.ch/visualize/316218/941/chargeInner_PXLayer_1/

Upon further investigation, I found that these histograms are parsed from three 2018 CSV files, all parsed on 30 Sep 2022. The exact addresses for these files are as follows:

/eos/project/c/cmsml4dc/ML_2020/UL2018_Data/DF2018A_1D_Complete/ZeroBias_2018A_DataFrame_1D_1.csv
/eos/project/c/cmsml4dc/ML_2020/UL2018_Data/DF2018A_1D_Complete/ZeroBias_2018A_DataFrame_1D_10.csv
/eos/project/c/cmsml4dc/ML_2020/UL2018_Data/DF2018A_1D_Complete/ZeroBias_2018A_DataFrame_1D_11.csv

According to histogram file manager, these three files are the only ones that are parsed out of all files in 2018A era. For now, I will re-parse the file using the manager and see if this issue is fixed.

Thanks,
Vichayanun