"Treat missing/null values as 0" Does not work for line charts with datetime scale x-axis

[orenpai]

Issue Summary

When creating a line chart with a datetime based x-axis, from a table with missing dates ("holes"), the line chart continues as if no data was present, even though the option "Treat missing/null values as 0" is turned on. In contrast, bar charts work as expected - in which the bar is nonexistent (effectively size 0) on those missing dates.

Steps to Reproduce

You can use this csv data as an example, or use the attached CSV. Incoming_Users_2020_03_09.csv.txt

dt,installs 06/02/2020,1 10/02/2020,8 11/02/2020,5 12/02/2020,1

(Please note European date format, switch month and day if necessary)

Create a chart visualization (x-axis is dt, y axis is installs); Make sure the "Treat missing/null values as 0" checkbox is selected. In the x-axis settings make sure the scale is Datetime (default). Notice how the chart line continues straight in all dates between 06/02 and 10/02, as if they value continued to be "1" for these dates (even though indeed no marker is present when you hover the chart with the mouse cursor). Switch to bar chart - all bars in the same dates show a value of 0 (no bar). Notice how unchecking and checking the checkbox "Treat missing/null values as 0" does not alter either of these charts.

Screenshots attached

The expected behavior is that when the checkbox is checked, the line chart would go to 0 on the dates that are not available in the table, similar to how the bar chart looks. For the bar chart, if the checkbox is unchecked, I would expect the same bar value to be kept, similar to how the line chart is.

• Redash Version: 8.0.0+b32245 (a16f551e)
• Browser/OS: Chrome Version 80.0.3987.122 (Official Build) (64-bit)
• How did you install Redash: AWS ami-0b97435028ca44fcc

[brad-natelborg]

Agreed - was just looking into this same problem.