ItemList::removeItem can remove multiple Items at once

[benjaminpick]

In writing #1034, I discovered another potential bug:

Imagine adding an item twice:

$item = (new Item)->setName('blue car');
$itemList->addItem( $item );
$itemList->addItem( (new Item)->setName('blue car') );
$itemList->removeItem($item);

How many Items are now in the $itemList? Yes, none at all. This is because array_diff does not compare by reference, but by JSON representation of the internal state.

Is this on purpose?
(The same issue exists with many other PaypalModels.)

[bluk]

This is known behavior in this convenience method. It should be rare that you have the same items or other objects with the same exact JSON representation in real world scenarios. If you must control the exact items, you can use the setItems or equivalent setter for the property.