fix(colmi): preserve quarter-hour offset in activity buckets (up to ~75% step undercount)#87
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saksham2001 merged 2 commits intoJul 15, 2026
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The activity-history decoder built each bucket's timestamp as `hour = v[4]/4, minute = 0`, discarding the within-hour quarter (`v[4] % 4`). Daily step/distance totals are the sum of buckets keyed by their start epoch, so all four quarter-hour buckets of an hour collapsed onto HH:00 and overwrote each other — undercounting a normally-worn Colmi/R02 ring's steps and distance by up to ~75%. Set `minute = (v[4] % 4) * 15` so each quarter keeps a distinct epoch. Existing tests passed only because their captured buckets happened to use quarter indices that were exact multiples of 4 (one per hour); add a regression test with two same-hour quarters.
saksham2001
approved these changes
Jul 15, 2026
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Bug
ColmiDecoder.decodeActivityHistorybuilt each activity bucket's timestamp ashour = v[4] / 4, minute = 0, dropping the within-hour quarter (v[4] % 4).Daily step/distance totals are computed as the sum of buckets keyed by their start epoch (
ActivityService.applyActivityBucketupserts bystartEpoch). So all four quarter-hour buckets of a given hour collapsed ontoHH:00:00and overwrote each other — only the last-written quarter survived. A normally-worn Colmi/R02 ring that's active in more than one quarter of an hour has its steps and distance undercounted by up to ~75%.Fix
Set
minute = (v[4] % 4) * 15so each quarter-hour bucket keeps a distinct timestamp/epoch. (v[4]is the quarter-of-day index 0…95 →hour = q/4,minute = (q%4)*15.)Why tests didn't catch it
The existing
ColmiDecoderTestshad no coverage for the activity-history bucket path, and the captured fixtures elsewhere used quarter indices that were exact multiples of 4 (one bucket per hour), so no collision occurred. AddedtestActivityHistoryPreservesQuarterHourOffset— two same-hour quarters (6 → 01:30, 7 → 01:45) must decode to distinct timestamps. FullColmiDecoderTestssuite green.Found via a code audit; connected-ring, all Colmi/R02-family users.