claude
8688a60ded
The single-file ledger had grown to 2968 lines / ~42k tokens, mixing current design law with accreted history: 59 cycle-stamped realization blocks, 18 [HISTORY] passages, 22 supersession markers, and the C10 / C22 / C24 reframe sagas layered several supersessions deep. A code-grounding audit (31 agents, adversarially verified) confirmed 11 defects stated as current truth: stale crate homes from the C28 #288 roster split (cost nodes, PositionManagement, PositionEvent, Session), the renamed InputSpec->PortSpec, the pre-#241 project model in C16 and the open-threads section, a stale HarnessKind retirement deferral in C24, and three C28-internal inconsistencies. New shape, per the ailang precedent: - INDEX.md stays the sole addressable entry point: foundation, external components, a C-id-keyed contract map (one line per contract), and only the genuinely open architectural threads. - contracts/cNN-<slug>.md carries each contract's current truth only: Guarantee / Forbids / Why with ratified refinements integrated, plus a code-anchored Current state. All confirmed defects are fixed here; crate anchors were re-verified against the tree. - contracts/cNN-<slug>.history.md (18 sidecars) and INDEX.history.md preserve every superseded block verbatim, stamps and issue refs intact, under a frozen-record banner. Nothing was deleted: superseded design intent remains an addressable working-tree artifact, off the per-cycle audit walk. - Ledger discipline is now stated in INDEX.md: live files are edited in place at cycle close, superseded text moves verbatim to the sidecar, and a supersession marker in a live file is itself an audit finding. Every contract file was verified against its old text by an independent zero-loss pass (statement-by-statement) plus a code-accuracy spot check; C-ids and contract titles are unchanged, so existing C-id citations in code, tests, and issues resolve as before.
37 lines
1.6 KiB
Markdown
37 lines
1.6 KiB
Markdown
# C2 — Causality / no look-ahead
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**Guarantee.** A node sees only the past. Input history is a read-only window
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that ends at the current cursor; a resampler emits a bar only once it is
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complete.
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**Forbids.** Any node access to data with `timestamp > now`; emitting a partial
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/ still-forming bar.
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**Why.** Look-ahead is the cardinal backtester bug — a fast backtester that
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leaks the future is worse than none. Making the future *physically absent* from
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what a node receives beats merely discouraging it.
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## Current state
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A node's `eval` receives `Ctx::new(&inputs, ts)` (`crates/aura-engine/src/harness.rs`):
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the input windows are read-only slices whose head (`window[0]`) is the value
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pushed at or before the current `cycle_id`. The engine forwards exactly one
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merged record per cycle in ascending timestamp order, so a node structurally
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cannot reach a record with `timestamp > now` — the future is absent from what it
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receives, not merely off-limits.
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The resampler (`crates/aura-market/src/resample.rs`) emits a completed coarse bar
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only on bucket rollover; a still-forming bar is never emitted, and an incomplete
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final bucket with no following rollover tick simply never emits. The completed
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bar carries no timestamp of its own — it takes the rollover instant, the close
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instant of the bar just emitted (C4).
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## See also
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- [C3](c03-single-merge.md) — the single ingestion merge is what makes a
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read-only, monotone cursor possible.
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- [C4](c04-cycle-granularity.md) — the data-driven cycle clock the cursor
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advances along.
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- [C5](c05-freshness-gating.md) — held (stale) values are real past values, not
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a look-ahead escape hatch.
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