The persistent mood-rollup writer bucketed on the UTC truncation of
`mood_logged_at` and ignored the canonical per-row `MoodEntry.date`
label. Every coverage-miss fallback keys on `entry.date`, so the rollup
tier disagreed with the fallback and with the day the user logged the
mood: a late-evening or after-midnight local mood landed on the wrong
calendar day, and the label shifted the moment the boot backfill flipped
a user from the live fallback onto the rollup tier.
Key every bucket off the stored `date` label instead — DAY, WEEK, MONTH
and YEAR — with `bucket_start` set to that label's UTC-midnight instant.
The rollup is now byte-identical to the live `entry.date` fallback and
timezone-independent by construction: DST correctness stays where it
already lives, in `moodDateKey` at write time. No consumer changes, no
schema change; every rollup reader already formats `bucket_start` as a
UTC day label.
Migration 0269 empties `mood_entry_rollups` so the boot-time
full-backfill worker re-mints every user's buckets under the corrected
keying; the worker now deletes-then-refolds so it is self-cleaning
against any row left by an older instance. While the table is empty,
reads fall back to the live `date`-keyed walk, which was already
correct, so there is no window where a wrong day is shown.
The dashboard snapshot and the /api/mood/analytics route each carried a
hand-copied rollup read, coverage fallback, and daily summarize of the
same numbers. Two reads of one metric is the seam where the dashboard
tile and the insights mood sparkline can drift apart.
Extract buildMoodDailySeries as the single mood engine and route both
callers through it, so the same mood number reads identically on the
dashboard, the insights surface, and the iOS client.
Marc-André Bombeck