defaultValue for SelectArrayInput inside ArrayInput -> SimpleFormIterator -> FormDataConsumer is not applied

[ghost91-]

What you were expecting:
When using a SelectArrayInput inside ArrayInput -> SimpleFormIterator -> FormDataConsumer, when removing an element from the ArrayInput (either by clicking the "Remove" button or the "Clear the list" button), and then adding a new element, the defaultValue for the SelectArrayInput is used for the new element.

What happened instead:
When doing the above, the SelectArrayInput of the new element is empty.

The underlying reason seems to be that the property for the SelectArrayInput is being set to null instead of removing it from the record, for some reason. SelectArrayInput has some special handling to ensure that the value always is an array, but it simply falls back to the empty array in this case. We ran into this problem with a custom component that works similar to SelectArrayInput, but didn't catch this, so our component actually crashed, because it received "" as value, instead of an array (the null seems to be converted to "" by the useInput hook).

Steps to reproduce:

• Open https://stackblitz.com/edit/github-5j4apk
• Got to the comment list and edit the single existing comment
• Click the "Remove" button for the single existing item in the ArrayInput labeled "Items".
• Click the "Add" button
• Observe that nothing is selected in the "data" SelectArrayInput (while it should have "Foo" selected).

Environment

• React-admin version: 4.13.0
• React version: 17/18
• Browser: Firefox/Chromium

[djhi]

Reproduced, thanks

[ghost91-]

Thanks for fixing this so quickly! I'm always amazed with how quickly you react to bug reports! Big props to you!