Reports 500 (Internal Server Error):
- app.py: Replace NaN/Infinity->null before json.loads() in both
/reports and /api/runs routes. Old summary.json files with invalid
NaN are now handled transparently.
- reports/writer.py: Added _safe_val() helper using math.isfinite().
All summary.json values now use safe rounding (NaN->0, Inf->0).
No new hypotheses (optimizer stops after 1 iter):
- optimizer_loop.py: Changed dedup from DB-wide history to
session-scoped (self.session_tested_deltas). Previous runs from
old sessions no longer block new hypothesis proposals.
- Each tested hypothesis is tracked within the session only.
Result: optimizer now runs multiple iterations, scores are valid
numbers, reports page loads without 500.
- NaN composite score: dropna().mean() on empty series returns NaN,
nan is truthy so (nan or 0)=nan. Fixed: use None when no MFE data
so scorer uses 0.5 fallback instead of propagating NaN.
- Analysis stopping: gate WFV was importing from main.execute_run
(old CLI code that uses broken runner). Fixed: gate.run_walk_forward
now accepts an executor callable from optimizer_loop.
- Back to Dashboard opened blank tab: Reports button used
window.open(_blank). Fixed: same-tab navigation + history.back().
- NaN in reports card: downstream of composite_score NaN above.
LEGSTECH Optimizer