pub fn validate_next(
log: &[EventEnvelope],
candidate: &EventEnvelope,
) -> Result<(), ValidationError>Expand description
Decides whether candidate is the one legal next event to append to log.
log is assumed well formed (the guard’s own invariant: it is either empty
or a prefix built by appending only validated events). The check reads the
log’s tail, not its whole history, so it is cheap to run on every append.
§Errors
A ValidationError naming the first rule the candidate breaks. See the
variants for the full list; the module docs explain how each maps to a
cursor rule.