test(freshness): pin against calendar-day regression in freshness functions#298
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AST-walk regression pin: every production function whose name matches
fresh|stale|preflight|postflight must not contain ``.days`` calendar
arithmetic. Closes the cross-repo defect class surfaced by the
2026-05-24 Sunday SF recovery: calendar-day gates trip on every
post-Saturday redrive even when data carries the most recent NYSE close.
Escape hatch: inline ``# noqa: trading-day`` marker on the same line
documents calendar-day correctness at that specific call site.
Explicit allowlist: ``collectors/prices._find_stale_fast`` checks S3
LastModified timestamp (write-recency, not data-freshness) and is
correctly calendar-day; allowlist verified by a second test that
ensures the named function actually exists in the named file.
Pin passes on current clean state (all 5 freshness sites migrated to
``alpha_engine_lib.dates.{trading_days_stale, is_fresh_in_trading_days}``
in PR #297). Would catch any future PR that adds calendar-day
arithmetic to a freshness-named function.
Composes with the lib v0.27.0 chokepoint (lib #59) + the cross-repo
migration arc (predictor #191, research #222).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
AST-walk regression pin: production functions whose name matches
fresh|stale|preflight|postflightmust not contain.dayscalendar arithmetic. Closes the cross-repo defect class surfaced by the 2026-05-24 Sunday SF recovery and the migration arc that followed.Why
The 2026-05-24 incident:
validators/postflight.py::_check_macro_spy_freshused(run_date - last_date).days > 1and blocked the Sunday redrive even though macro.SPY carried Friday's close (the most recent NYSE session). Audit found the same pattern in 7 sites across data/predictor/research. All migrated toalpha_engine_lib.dates.{trading_days_stale, is_fresh_in_trading_days}in lib v0.27.0 + the migration arc (data #297, predictor #191, research #222).Without this pin, a future bug fix that introduces
(today - last_date).days > Ninsidecheck_X_fresh/validate_stale_Y/_check_Z_preflightwould slip past code review and rediscover the gate-trips-on-redrive failure mode.Mechanism
.pyfiles under the repo root (skip.venv,__pycache__,tests,.claude,.git,build).FunctionDefwhose lowercased name matches(fresh|stale|preflight|postflight), scan the function body for any.daysattribute access.# noqa: trading-daymarker.Per-repo allowlists exist for documented exceptions (only
alpha-engine-datahas one:collectors/prices._find_stale_fastis a write-recency check on S3LastModified, correctly calendar-day).Test plan
test_allowlist_entries_are_realensures any allowlisted (file, function) tuple actually exists — drift-detector for the allowlist itselfComposes with
🤖 Generated with Claude Code