The three recurrence arrays are read CONJUNCTIVELY by
AlternateScheduleSelector.GetScheduleForDate, so an empty set matches no date.
`?? []` on an omitted array therefore returned HTTP 200 while storing an
alternate-schedule or template item that could never apply, silently -- while the
read side (#823) already read a NULL column as the All*() sets.
Absent and explicitly-empty are two different requests and get two answers:
ABSENT (missing, or explicit null) normalizes to AlternateScheduleSelector.All*(),
the same symbols the read side substitutes; EXPLICIT [] is rejected with a 422
naming the consequence, via RecurrenceSetBounds called from both replace handlers.
The rejection lives in the handlers, not the controller, because
api.ffmpeg-profile-numeric-bounds' "accept an UNCHANGED bad value" rule binds
hardest here: both PUT paths are whole-list replaces, so rejecting a pre-existing
empty set would make every OTHER item in the list uneditable. That comparison
needs the stored row. The validated set is derived from `incoming`, so the
highest-Index catch-all -- whose recurrence the handler discards -- is excluded by
construction.
Verified: full ErsatzTV.Tests suite green; three mutation proofs with disjoint
reddened sets; live-E2E against a real instance confirmed an OMITTED property
round-trips as unrestricted (the Newtonsoft missing-property chain unit tests
cannot reach), an explicit [] returns the 422, and [] on the catch-all is accepted.
Cross-family cold review BLOCKED the first implementation with 3 findings, all real
and all fixed; re-review returned MERGEABLE.
Follow-up #894 filed: the SPA can still build the empty state the server rejects.
fixes#880
Decisions-Edit: yes
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
