fix: lazy session resolver and one-time session_id backfill

src/db.py

@@ -8,9 +8,6 @@ from datetime import UTC, datetime
 from pathlib import Path
 from typing import Any
 
-from src.core.order_policy import classify_session_id
-from src.markets.schedule import MARKETS
-
 
 def init_db(db_path: str) -> sqlite3.Connection:
     """Initialize the trade logs database and return a connection."""
@@ -60,8 +57,10 @@ def init_db(db_path: str) -> sqlite3.Connection:
         conn.execute("ALTER TABLE trades ADD COLUMN decision_id TEXT")
     if "mode" not in columns:
         conn.execute("ALTER TABLE trades ADD COLUMN mode TEXT DEFAULT 'paper'")
+    session_id_added = False
     if "session_id" not in columns:
         conn.execute("ALTER TABLE trades ADD COLUMN session_id TEXT DEFAULT 'UNKNOWN'")
+        session_id_added = True
     if "strategy_pnl" not in columns:
         conn.execute("ALTER TABLE trades ADD COLUMN strategy_pnl REAL DEFAULT 0.0")
     if "fx_pnl" not in columns:
@@ -76,6 +75,7 @@ def init_db(db_path: str) -> sqlite3.Connection:
           AND fx_pnl = 0.0
         """
     )
+    if session_id_added:
         conn.execute(
             """
             UPDATE trades
@@ -232,10 +232,7 @@ def log_trade(
     """
     # Serialize selection context to JSON
     context_json = json.dumps(selection_context) if selection_context else None
-    resolved_session_id = session_id or "UNKNOWN"
-    market_info = MARKETS.get(market)
-    if session_id is None and market_info is not None:
-        resolved_session_id = classify_session_id(market_info)
+    resolved_session_id = _resolve_session_id(market=market, session_id=session_id)
     if strategy_pnl is None and fx_pnl is None:
         strategy_pnl = pnl
         fx_pnl = 0.0
@@ -277,6 +274,21 @@ def log_trade(
     conn.commit()
 
 
+def _resolve_session_id(*, market: str, session_id: str | None) -> str:
+    if session_id:
+        return session_id
+    try:
+        from src.core.order_policy import classify_session_id
+        from src.markets.schedule import MARKETS
+
+        market_info = MARKETS.get(market)
+        if market_info is not None:
+            return classify_session_id(market_info)
+    except Exception:
+        pass
+    return "UNKNOWN"
+
+
 def get_latest_buy_trade(
     conn: sqlite3.Connection, stock_code: str, market: str
 ) -> dict[str, Any] | None:

tests/test_db.py

@@ -297,3 +297,35 @@ def test_log_trade_persists_explicit_session_id() -> None:
     row = conn.execute("SELECT session_id FROM trades ORDER BY id DESC LIMIT 1").fetchone()
     assert row is not None
     assert row[0] == "US_PRE"
+
+
+def test_log_trade_auto_derives_session_id_when_not_provided() -> None:
+    conn = init_db(":memory:")
+    log_trade(
+        conn=conn,
+        stock_code="005930",
+        action="BUY",
+        confidence=70,
+        rationale="auto session",
+        market="KR",
+        exchange_code="KRX",
+    )
+    row = conn.execute("SELECT session_id FROM trades ORDER BY id DESC LIMIT 1").fetchone()
+    assert row is not None
+    assert row[0] != "UNKNOWN"
+
+
+def test_log_trade_unknown_market_falls_back_to_unknown_session() -> None:
+    conn = init_db(":memory:")
+    log_trade(
+        conn=conn,
+        stock_code="X",
+        action="BUY",
+        confidence=70,
+        rationale="unknown market",
+        market="MARS",
+        exchange_code="MARS",
+    )
+    row = conn.execute("SELECT session_id FROM trades ORDER BY id DESC LIMIT 1").fetchone()
+    assert row is not None
+    assert row[0] == "UNKNOWN"