Two faults, both introduced by the tick feed, both visible as a huge bar that
flattened the price scale.
A LEVEL_ONE_FUTURES update arrived carrying LAST_PRICE: 0. The parser rejected
None, but 0 is not None, so a minute opened at zero — o=0.0 h=7777.25 l=0.0 —
and provisional_higher carried that low into 5m, 15m, 30m, 1h and the daily bar.
Non-positive prices are treated as absent now, so the last real price carries
forward and the update still counts as the trade it is.
Separately, store.put replaced a bar only when it matched the tail. That was
sufficient while one closed bar arrived per minute, but ticks open the next
minute before CHART_FUTURES delivers the previous one, so the exchange's own bar
stopped matching the tail and was silently dropped — leaving the tick-built
approximation, with its partial volume, in place permanently. put now searches
back a bounded number of buckets for the one it belongs to, and refuses to let a
provisional bar overwrite a settled one.
Tests cover all three invariants: a zero price parses as a trade with no price,
a late closed bar replaces its bucket and keeps the exchange's volume, and a
tick cannot overwrite a settled bar.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
