@Piinks @chinmoy12c I created the PR to continue the discussion from #84816

I made Draggable.data non nullable and dummy fixed the lints for now. Should I do anything else or should I make the code support null?

@Piinks, thank you for the review. I'm okay to change the code to not make data a required T but a T?. That would also induce some breaking changes though.

For example

would become something like

widget.onAccept?.call(avatar.data as T?); 
widget.onAcceptWithDetails?.call(DragTargetDetails<T?>(data: avatar.data as T?, offset: avatar._lastOffset!)); 

which will force me to change the signature of onAccept and onAcceptWithDetails.

Also, I might need to change DragTargetDetails to make its field data nullable and non-required.

Are you fine with it or do you see a better approach?

The issue is that Draggable<T> accepts a nullable/non-required T? data:

So data can be null.

But DragTarget assumes data is never null and uses data! as T. For example in didDrop:

which throws a Null check operator used on a null value exception when data is actually null.

An alternative that could dodge breaking changes would be to do something like:

if (avatar.data != null) {
  widget.onAccept?.call(avatar.data! as T); 
  widget.onAcceptWithDetails?.call(DragTargetDetails<T>(data: avatar.data! as T, offset: avatar._lastOffset!));
}

It would not require us to change any function signature.

What do you think?

It would not require us to change any function signature.

That sounds reasonable to me. :) Thanks!

@Piinks What do you think of fix: Don't call .data! when it is null ?

(Sorry I forced pushed, it was simpler than reverting my changes that were conflicting with main)

@Piinks is there something else I should do on this PR or does it look good to you ?

is there something else I should do on this PR or does it look good to you ?

This is still marked as a draft, can you mark it ready for review? :)

@Piinks Do you have any more feedback on this PR?