Can document.objects contain non-TopLevel objects?

[jakebeal]

I just noticed that document.objects is of type List[Identified], rather than List[TopLevel] like I had expected it would be. Is there a case in which it can contain a non-TopLevel object? If so, what is it? If not, can we change it to List[TopLevel]?

[bbartley]

If I remember correctly, the object store temporarily contains Identified objects during loading of a document. The objects are first deserialized into this store as a flat list, and then subsequently structured into a tree.

Since the type hints are not enforced though, we could still change the type hint to indicate List[TopLevel]

[jakebeal]

I think they may go into document.orphans instead of document.objects in any case?

[tcmitchell]

Document.objects should ultimately contain only instances of TopLevel, so List[TopLevel] is likely a better type annotation. It may be the case, as @bbartley says, that some non-TopLevel objects are temporarily in Document.objects as the loading goes through its phases. These objects will end up in Document.orphans eventually, but early in the loading process we don't know they are orphans.

We should make this change to the type annotation and we should ensure that Document.objects always and only contains instances of TopLevel. This may require the use of an additional temporary list somewhere to avoid writing to Document.objects.