Scan survives score-refresh failures; fix expired-ORM crash after rollback

A scoring error no longer skips setup detection for the ticker: the
rollback already restores a clean transaction, and qualification
re-gates on live scores at alert time, so a stale score is recoverable
but a skipped scan is not.

Iterating symbol strings instead of Ticker instances fixes a latent
crash the new regression test caught: rollback() expires ORM objects
regardless of expire_on_commit, so touching ticker.symbol in the except
handler triggered sync lazy-loading, which raises on an AsyncSession
and killed the whole scan on the first per-ticker error.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/services/rr_scanner_service.py

@@ -553,9 +553,12 @@ async def scan_all_tickers(
     ``progress_callback(processed, total, current_symbol)`` is invoked as each
     ticker is scanned so callers (e.g. the scheduler) can surface live progress.
     """
-    result = await db.execute(select(Ticker).order_by(Ticker.symbol))
-    tickers = list(result.scalars().all())
-    total = len(tickers)
+    # Plain strings, not Ticker instances: the rollbacks below expire any ORM
+    # objects held across them, and touching an expired attribute afterwards
+    # triggers sync lazy-loading, which raises on an AsyncSession.
+    result = await db.execute(select(Ticker.symbol).order_by(Ticker.symbol))
+    symbols = list(result.scalars().all())
+    total = len(symbols)
 
     # Rank the universe up front so each new setup carries both the residual
     # activation gate percentile and the promoted production ordering score.
@@ -571,34 +574,35 @@ async def scan_all_tickers(
         ranks = {}
 
     all_setups: list[TradeSetup] = []
-    for index, ticker in enumerate(tickers):
+    for index, symbol in enumerate(symbols):
         if progress_callback is not None:
-            progress_callback(index, total, ticker.symbol)
+            progress_callback(index, total, symbol)
         # Refresh scores first so the scheduled scan works off current data.
         # Nothing else marks scores stale, so without this they'd never update
-        # for tickers the user doesn't manually fetch.
+        # for tickers the user doesn't manually fetch. A refresh failure still
+        # scans the ticker: qualification re-gates on live scores at alert
+        # time, so a stale score is recoverable but a skipped scan is not.
         try:
             from app.services import scoring_service
 
-            await scoring_service.compute_all_dimensions(db, ticker.symbol)
-            await scoring_service.compute_composite_score(db, ticker.symbol)
+            await scoring_service.compute_all_dimensions(db, symbol)
+            await scoring_service.compute_composite_score(db, symbol)
             await db.commit()
         except Exception:
             await db.rollback()
-            logger.exception("Error refreshing scores for %s", ticker.symbol)
-            continue
+            logger.exception("Error refreshing scores for %s", symbol)
 
         try:
             setups = await scan_ticker(
-                db, ticker.symbol, rr_threshold, atr_multiplier,
-                momentum_percentile=(ranks.get(ticker.symbol) or {}).get("momentum_percentile"),
-                strategy_rank=(ranks.get(ticker.symbol) or {}).get("strategy_rank"),
-                volatility_percentile=(ranks.get(ticker.symbol) or {}).get("volatility_percentile"),
+                db, symbol, rr_threshold, atr_multiplier,
+                momentum_percentile=(ranks.get(symbol) or {}).get("momentum_percentile"),
+                strategy_rank=(ranks.get(symbol) or {}).get("strategy_rank"),
+                volatility_percentile=(ranks.get(symbol) or {}).get("volatility_percentile"),
             )
             all_setups.extend(setups)
         except Exception:
             await db.rollback()
-            logger.exception("Error scanning ticker %s", ticker.symbol)
+            logger.exception("Error scanning ticker %s", symbol)
 
     if progress_callback is not None and total:
         progress_callback(total, total, "")

tests/unit/test_rr_scanner_scan_all.py

@@ -0,0 +1,61 @@
+"""Tests for scan_all_tickers orchestration: error isolation between phases."""
+
+from __future__ import annotations
+
+import pytest
+
+from app.models.ticker import Ticker
+from app.services import rr_scanner_service, scoring_service
+from tests.conftest import _test_session_factory  # type: ignore
+
+
+@pytest.fixture
+async def session():
+    async with _test_session_factory() as s:
+        yield s
+
+
+async def test_scan_proceeds_when_score_refresh_fails(session, monkeypatch):
+    """A scoring failure must not skip setup detection for the ticker.
+
+    Qualification re-gates on live scores at alert time, so a stale score is
+    recoverable — a skipped scan is not.
+    """
+    session.add(Ticker(symbol="AAA"))
+    await session.commit()
+
+    async def _boom(db, symbol):
+        raise RuntimeError("scoring unavailable")
+
+    scanned: list[str] = []
+
+    async def _fake_scan_ticker(db, symbol, *args, **kwargs):
+        scanned.append(symbol)
+        return []
+
+    monkeypatch.setattr(scoring_service, "compute_all_dimensions", _boom)
+    monkeypatch.setattr(rr_scanner_service, "scan_ticker", _fake_scan_ticker)
+
+    setups = await rr_scanner_service.scan_all_tickers(session)
+
+    assert scanned == ["AAA"]
+    assert setups == []
+
+
+async def test_scan_error_does_not_stop_later_tickers(session, monkeypatch):
+    session.add_all([Ticker(symbol="AAA"), Ticker(symbol="BBB")])
+    await session.commit()
+
+    scanned: list[str] = []
+
+    async def _fake_scan_ticker(db, symbol, *args, **kwargs):
+        scanned.append(symbol)
+        if symbol == "AAA":
+            raise RuntimeError("scan blew up")
+        return []
+
+    monkeypatch.setattr(rr_scanner_service, "scan_ticker", _fake_scan_ticker)
+
+    await rr_scanner_service.scan_all_tickers(session)
+
+    assert scanned == ["AAA", "BBB"]