Write A Keyed Record And Its Producer Mapping
What It Does
Producer mapping translates external identity into a destination and revision decision. The domain write and mapping share a transaction, with a known gap for simultaneous first deliveries of one key.
The Flow
When Something Fails
A refused item commits neither its domain change nor its mapping. Existing-key guards preserve intervening edits under reject. First-key concurrency can still create an additional destination, so stable producer identity is weaker than the library commentary promises.
Open Design Questions
Producer identity needs a first-key concurrency safeguard before the stronger mapping guarantee can be accepted.