remove function duplicate the list

[mdouaihy]

Describe the bug
The feel expression remove([1,2,3], 0) returns [1,2,3,1,2,3].

This bug is due to the below code

  private def removeFunction = builtinFunction(
    params = List("list", "position"),
    invoke = { case List(ValList(list), ValNumber(position)) =>
      ValList(
        list.take(listIndex(list, position.intValue)) ++ list.drop(listIndex(list, position.intValue + 1)
        )
      )
    }
  )

The goal of this code is to

• take the first n elements list.take(listIndex(list, position.intValue))
• drop the n+1 elements list.drop(listIndex(list, position.intValue + 1)
• concatenate the resuls

The problem is

• when n is equal to 0, listIndex(list, position.intValue) returns 3 and listIndex(list, position.intValue + 1) is returning 0.
• The take part is taking the whole list
• The drop part is taking the whole list
• The concatenate is duplicating the list.

where ``````

To Reproduce
Execute the feel expression remove([1,2,3], 0)

Expected behavior
Returns null since position 0 is an invalid argument.

Environment

• FEEL engine version: latest version,

[saig0]

@mdouaihy thank you for reporting. 👍

I can confirm the bug in the version 1.19.0. ✅

[saig0]

I adjusted the expected behavior. If the position is 0, the function should return null.

@mdouaihy suggested returning the original list. According to the DMN specification, zero is an invalid argument. Returning null aligns with other functions.