Optimize signal read paths and enforce score invariants

app/services/rr_scanner_service.py

@@ -566,6 +566,7 @@ async def scan_all_tickers(
 
         ranks = await momentum_service.compute_activation_ranks(db)
     except Exception:
+        await db.rollback()
         logger.exception("Activation ranking refresh failed")
         ranks = {}
 
@@ -573,19 +574,21 @@ async def scan_all_tickers(
     for index, ticker in enumerate(tickers):
         if progress_callback is not None:
             progress_callback(index, total, ticker.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.
         try:
-            # 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.
-            try:
-                from app.services import scoring_service
+            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 db.commit()
-            except Exception:
-                logger.exception("Error refreshing scores for %s", ticker.symbol)
+            await scoring_service.compute_all_dimensions(db, ticker.symbol)
+            await scoring_service.compute_composite_score(db, ticker.symbol)
+            await db.commit()
+        except Exception:
+            await db.rollback()
+            logger.exception("Error refreshing scores for %s", ticker.symbol)
+            continue
 
+        try:
             setups = await scan_ticker(
                 db, ticker.symbol, rr_threshold, atr_multiplier,
                 momentum_percentile=(ranks.get(ticker.symbol) or {}).get("momentum_percentile"),
@@ -594,6 +597,7 @@ async def scan_all_tickers(
             )
             all_setups.extend(setups)
         except Exception:
+            await db.rollback()
             logger.exception("Error scanning ticker %s", ticker.symbol)
 
     if progress_callback is not None and total: