zeekayandClaude Opus 4.8 2a164daa61 fix(dex): exact-integer ZAP wire + ledger-in-root — kill cross-arch/restart execRoot forks, silent money desync, and ceil/floor strand ...

Consensus-correctness fix for the native DEX settlement VM. Root cause of the
launch-blocking forks: order size/price were IEEE-754 float64 on the ZAP wire, so
every validator re-derived the settlement integer via uint64(float)/int64(float*1e8),
whose out-of-range result is implementation-defined per the Go spec and DIFFERS BY
CPU ARCHITECTURE (arm64 saturates to 2^64-1; amd64 wraps to 2^63). Two honest
validators on different archs then derived different reserves/balances/fills from the
SAME ordered block.

F1/F3/F5 — exact-integer size/price end to end:
- pkg/zapwire: Place/Submit/Fill carry price as uint64 fixed-point (×1e8 = PriceInt)
  and size as uint64 atomic base units. No float64 on the wire. Removed PutFloat64/
  Float64. Decode is exact bytes->uint64 (deterministic on every arch).
- pkg/dchain/execute: decode the exact integers, set the authoritative PriceUnits/
  SizeUnits lane; the float Price/Size become derived projections only (never a
  source of a consensus value). Reject price==0/size==0/price>maxPriceUnits.
- pkg/dex/persist: the DEXOrder/DEXTrade row stores the EXACT PriceInt (in
  DEXPrice.Integer) and EXACT base units (Quantity/Remaining); RowToOrder restores
  the integer lane verbatim (identity — no float round-trip) and Filled=Qty-Remaining.
  Removed floatToFixedQty/fixedQtyToFloat/floatToFixedPrice (the non-idempotent
  round(size*1e8)/Q64.64 encoding that clamped at ~1.845e11 and forked on restart).
- pkg/dex matcher: cross and level-key on the exact integer PriceUnits.
- pkg/dchain/settle: orderLock/floorsToZeroLock take exact integers; removed
  sizeToUnits/priceToInt float conversions and the dead restoreIntegerLane.

F2 — commit the custody ledger into the execution root:
- state.ComposeRoot/ExecutionRoot gain a ledgerRoot term (Merkle over balance:/
  locked:/orderasset: rows). Validators can no longer finalize agreeing on the book
  while holding different money.

F4 — release the ceil-lock/floor-charge residual on full fill:
- decrementMakerReserves now closes a fully-filled maker's reserve and returns the
  ceil(size*price)-floor residual to the owner (a filled order can never be
  cancelled), through the same unlock path a cancel uses. No more permanently
  frozen quote.

PROVEN: the two-phase cross-arch harness (arm64 build / amd64 Rosetta verify) now
derives byte-identical execRoots AND byte-identical custody ledgers for the
identical block (uint64(1e20) still differs at the language level — 0xffff.. vs
0x8000.. — but the exact-integer wire freezes the value in the bytes so no
per-validator float->int conversion remains). Red guards flipped to assert the fix;
conservation/byzantine/batch-parity/KAT/e2e all green (go test ./... -count=1),
go vet clean.

OUT OF SCOPE (flagged, NOT fixed here): redteam_unbacked_deposit_test documents a
SEPARATE critical finding (F9) — dex_deposit credits an arbitrary self-signed amount
with no C-side backing proof, exposed on the public RPC. That needs an access-control/
custody-model decision, not a mechanical fix, and is left for a follow-up.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

2026-07-02 09:42:54 -07:00

..

dexbench

fix(dex): exact-integer ZAP wire + ledger-in-root — kill cross-arch/restart execRoot forks, silent money desync, and ceil/floor strand

2026-07-02 09:42:54 -07:00

dexd

refactor(dex): fold pkg/lx into pkg/dex — one matcher, one package

2026-07-02 00:57:08 -07:00