[BUG] Unable to remove last element in settings list

Unable to remove last element in settings list

Request Type

Bug

Work Environment

Problem Description

Disclaimer: I can't test 3.1.0-1 since the migration of my DB fails, but this problem does not seem to have been reported.

It is not possible to remove the last item in a settings list (i.e. an item with "multi": true):

This is not only a UI bug, since this propagates down to e.g. Cortex Analyzers. One would expect to receive a empty list (or at least a None for the list itself) if no items are configured. Instead, Cortex creates a list with a None object in position 0 ([None]).

Steps to Reproduce

1. Create a Analyzer config JSON with multi = true and required = false
2. Create an instance of the config in Cortex
3. Try to remove the last item of the configuration
4. If you run it in debug or print it out, you will see a list that contains a None element

Possible Solutions

1. Let users remove the last element in a list via the UI
2. If no element are present, return an actual empty list
3. If an empty string is present in a multi input field, actually pass it on as empty string, not as None (i.e. [""] instead of [None])

Start with the settings list behavior for configurations marked multi=true and required=false, then trace how an empty configuration is passed to Cortex Analyzers. Reproduce the final-item removal case from the listed steps and verify that no configured items produce an empty list rather than [None].