Ref T13519. This is a little fuzzy, but I think the workflow here is:
- View an intradiff, generating an ephemeral comparison changeset with no changeset ID. This produces a state key of "*".
- Apply "hidden" state changes to the changeset.
- View some other intradiff and/or diff view.
- The code attempts to use "*" as a changset ID?
I'm not entirely sure this is accurate; this was observed in production and I couldn't get a clean reproduction case locally.
Optimistically, try making changeset IDs explicit rather than relying on state keys to be "usually changeset-ID-like".