This invariant to check that the metadata has not been cleared when calling cleanUpRange may not be valid. It seems that it would be possible to hit this invariant with this existing use of cleanUpRange, in the case where the collection gets dropped and a refresh occurs after the migration completes but before cleanUpRange is called here. It will also be possible to hit this invariant with the addition of new code in the resumable range deleter project.

We should verify whether this should truly be an invariant and:

• If so, fix the existing bugs around usages of cleanUpRange
• If not, change the invariant to an error or otherwise handle this case appropriately.