ENA-121 Cancelling a csv import deletes all items in the list

[unyxium]

Expected Behavior

When importing a .csv file to a list, a browser prompt allows the user to select which column to use from the file. Pressing cancel should cancel the operation and not make any changes to the project.

Actual Behavior

Pressing cancel causes all items currently in the list to get deleted.

Steps to Reproduce

In a list which already contains items, right click its monitor on the stage and click import. Select a .csv file stored on your computer and import it. The browser should have a prompt box show so that a column of the file can be imported. Press cancel. All items in the list have now been deleted even though the .csv file has not been imported.

Operating System and Browser

Windows 10, occurs on both Chrome and Edge

[BryceLTaylor]

I was able to confirm this behavior on Mac Chrome. It may be worth mentioning that if your .csv file only has one column that box does not appear so you can't see this behavior. If you cancel out of importing without selecting a csv file at all, then your old data will remain.

[Chessing234]

Opened #10080 for this. Root cause is that a cancelled prompt returns null, so parseInt(null, 10) is NaN and every row[NaN - 1] is undefined — the filter then drops them all and the list gets overwritten with an empty array. The fix bails out when the prompt is cancelled. And good catch @BryceLTaylor — single-column files skip the prompt entirely, so they're unaffected.