previewsPendingExit top-level constant
What cux_ship exits with when a preview wait reaches its deadline with
assets still processing.
Not a failure, and not zero either. Apple documents ingestion as taking up to twenty-four hours, so a deadline says "not yet" rather than "wrong" — but a caller that branches on exit status, and never on text, cannot tell "not yet" from "finished" if both are 0. The first consumer branches that way deliberately, after a status escaped from four regular expressions matched against stdout.
4 rather than 2, which screenshots flatten --check uses for "there is work
to do", and rather than 3, which uploadCollisionExit holds. The meanings
are close enough that reusing 2 is tempting, and that is the argument
against it: a wrapper branching on 2 would conflate a tree that needs
flattening with an asset Apple has not finished, and the codes here are one
vocabulary rather than one per command.
Implementation
const previewsPendingExit = 4;