OFI features at bar t were computed over [close(bar_t), close(bar_{t+1}))
— bar t+1's formation period — so 31 of 32 OFI dims at the policy's
input for bar t carried next-bar microstructure data. Per audit
`docs/lookahead-bias-audit-2026-04-28.md` §3, this is a DEFINITE leak
contaminating both training inputs and validation backtest.
Fix: shift the window backward to (close(bar_{t-1}), close(bar_t)] so
OFI at bar t uses only data accumulated during bar t's own formation.
Mirrors the correct `log_bar_duration` convention at
precompute_features.rs:567-575 (audit's smoking-gun citation).
Per feedback_no_partial_refactor, both write sites migrated in lockstep:
- crates/ml/examples/precompute_features.rs:441-475 (precompute path)
- crates/ml/src/trainers/dqn/data_loading.rs:396-448 (DBN fallback)
FXCACHE_VERSION bumped 6 → 7. PVC auto-regen via schema-hash check on
next deploy. Local regen:
./target/release/examples/precompute_features \
--data-dir test_data/futures-baseline \
--mbp10-data-dir test_data/futures-baseline-mbp10 \
--trades-data-dir test_data/futures-baseline-trades \
--output-dir test_data/feature-cache \
--symbol ES.FUT --data-source mbp10 --yes
Regression test added: tests/ofi_features_test.rs::
test_ofi_window_alignment_uses_formation_interval validates the new
partition_point predicates against a synthetic 5-bar dataset, including
an explicit anti-regression assertion that bar t+1 snapshots are NEVER
picked up for bar t.
dqn-wire-up-audit.md updated to reflect new contract for
`trainers/dqn/data_loading.rs`. Audit report
`docs/lookahead-bias-audit-2026-04-28.md` checked in alongside the fix.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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