Stacked area chart shows gaps when null values present

[vylc]

Chart has weird gaps when there are null values in the dataset. Expectation is that areas with null values are shaded a darker color to represent null or are not rendered (go to 0)

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• I have checked the superset logs for python stacktraces and included it here as text if there are any.
• I have reproduced the issue with at least the latest released version of superset.
• I have checked the issue tracker for the same issue and I haven't found one similar.

Superset version

Expected results

Actual results

Steps to reproduce

[mistercrunch]

I think the solution for this is around when we'll move away from nvd3. Unless we expose an option to replace nulls with zeroes that addresses this.

[kristw]

@conglei Is this one fixed by your bug bash?

[conglei]

@kristw. This is a separate issue. This is a bug introduced by nvd3

[ghost]

This issue was moved by kristw to apache-superset/superset-ui-plugins#54.