Value needs to be an array when setting value for a multiple select.

So the error is correct.

yes, but I did this PR for single select. when single select the value can be a Array too.

I'm not sure what you mean. When using a single select the value should be scalar (not an array). Are you saying you want to support setting an array for a single select?

yes, I want the support of array for a single select, because my single select option value is an array.

That sounds like an interesting use case and not one I expected. Could you share your example use case?

Internally we don't expect arrays and it might break in places so I'll need to check that.