Function compare_entries 

pub fn compare_entries(
    doc: &mut AutoCommit,
    entries: &[HistoryEntryId],
) -> Result<HistoryComparison, CompareError>

Compare the dependency frontier immediately before the selected changes to the frontier after every selected change. Concurrent changes outside the selection are excluded. Pending edits are neither committed nor included.

Errors

Returns CompareError::EmptySelection for an empty selection, CompareError::UnknownEntry for an unknown entry, or CompareError::Materialize when Automerge cannot build either snapshot.