How to correctly handle orphaned data in a __resolveReference

[jaspertandy]

I have a federated schema where you can message someone about an item on a site. On a long enough timeline, it may be that one of the items becomes unavailable and, thus, would return null in __resolveReference. However, the messages service would still hold a reference to it.

In my messages resolver:

  item: ({ itemId }) => (itemId ? { id: itemId } : null),

In my Item resolver:

  __resolveReference: ({ id }, { loaders: { itemById } }) => itemById.load(id),

All things being well, this runs fine. However, if my item resolver in messages returns { id: 'item that has now been deleted' } and __resolveReference now returns null, this causes an error if I was trying to query any mandatory fields on the returned Item (i.e. title is required).

I would expect that returning null from __resolveReference would override the { id: 'item that has now been deleted' } but it seems to be merging with that and then causing me problems!

So would you expect in this instance, rather than my __resolveReference returning null, should it return a representation that is like { id: 'item that has now been deleted', title: 'No longer available' } or is there something I can do essentially where my item resolver and __resolveReference are merged, in order to say "if __resolveReference is null, return null for everything"?

Sorry if this is something that's been asked before - I've searched around a lot but I feel like I'm not using the correct terms because I feel like it's a fairly common usecase! Thank you in advance.