An external id is half of every ingest dedup key — (userId, source,
externalId), (userId, externalSource, externalId), (userId, type,
source, externalId). Re-posting the same triple is idempotent and
returns the existing row, which holds only while the id is stable
across client launches. A client that serialised an opaque platform
object with its default object description sent a per-allocation
memory address instead, so no sweep ever matched its own earlier row
and each one minted a fresh record: a live instance grew 23 phantom
medications in a day, none of which could collect a dose, because the
dose side resolved through the same rotating string.
Add one shared classifier for identifiers that provably cannot be an
identity — an angle-bracketed object description carrying a hex
pointer, a bare 0x address, and a blank value — and wire it at every
surface that accepts a client-supplied externalId.
Single-entry creates refuse through the schema, so the client gets the
standard 422 multi-issue envelope with a message naming the shape it
sent and what to send instead. Batch and bulk surfaces classify per
entry and report the offending row as skipped with reason
unstable_external_id, leaving the rest of the payload to land: one bad
row must not stop a sync. Every refusal carries pinned wide-event meta
(count, shape, surface) and never the id itself.
A structural guard freezes both routes into the floor: a request-side
externalId declaration either applies the field check or carries a
marker naming the file that checks it per entry, and the guard verifies
that file really does. The backup-restore payload is the one exemption,
with its reason recorded — it replays ids the server itself wrote.
The sleep source-discrepancy annotation now reaches the surfaces: SleepNight
carries the MAIN session's annotation (naps never cross-compare), the analytics
slim slice / dashboard snapshot / iOS summary thread it additively, and the
dashboard sleep tile renders the shared discreet marker (extracted from the
sleep panel — one implementation, two surfaces). Served totals unchanged,
pinned by tests.
Apple Health medications groundwork (server side of the medication-import
request): IntakeSource gains APPLE_HEALTH; medications accept an external
mirror identity (source-exclusive by policy) and dose imports carry the HK
dose-event UUID — both idempotent per stable key, with the concurrent-create
race resolved to the winner. Migration 0239, additive only. Entries without
the new fields behave byte-identically.
Hardening: doctor-report aggregation + PDF charts compute ranges with loops
instead of spread calls — a report over a sample-dense year cannot overflow
the call stack (the class fixed for the Google Health full sync).
muhdusama