fix(HEL-356): preserve derived limit streaks

Co-authored-by: multica-agent <github@multica.ai>

backend/data/providers/tushare_daily.py

@@ -169,7 +169,16 @@ class DailyMarketMixin:
                 current = item.get(key)
                 if incoming in (None, "", "--"):
                     continue
-                if current in (None, "", "--", 0, 0.0):
+                # The daily fallback and the board pool can arrive at different
+                # times. Keep the stronger streak instead of freezing the
+                # provisional default at one or letting a stale pool lower it.
+                if key == "limit_times":
+                    item[key] = max(
+                        1,
+                        int(_number(current, 1)),
+                        int(_number(incoming, 1)),
+                    )
+                elif current in (None, "", "--", 0, 0.0):
                     item[key] = incoming
             merged.append(item)
         return merged

backend/data/providers/tushare_dashboard.py

@@ -55,16 +55,24 @@ class DashboardMixin:
             if not limit_rows:
                 limit_data_source = "derived"
                 notices.append("涨跌停高级接口当日数据尚未更新，已使用日线数据推算。")
-                limit_rows = self._derive_limits(trade_date, daily)
+                limit_rows = self._derive_limits(
+                    trade_date,
+                    daily,
+                    previous_limit_rows=previous_limit_rows,
+                )
         except TushareError as exc:
             limit_data_source = "derived"
             notices.append(f"涨跌停高级接口不可用，已使用日线数据推算：{exc}")
-            limit_rows = self._derive_limits(trade_date, daily)
             previous_daily = self._load_daily(previous_trade_date)
             previous_limit_rows = [
                 row for row in self._derive_limits(previous_trade_date, previous_daily)
                 if row.get("limit_type") == "U"
             ]
+            limit_rows = self._derive_limits(
+                trade_date,
+                daily,
+                previous_limit_rows=previous_limit_rows,
+            )
 
         up_rows = [row for row in limit_rows if row.get("limit_type") == "U"]
         down_rows = [row for row in limit_rows if row.get("limit_type") == "D"]

config/architecture-inventory.json

@@ -498,8 +498,8 @@
     },
     {
       "path": "backend/data/providers/tushare_dashboard.py",
-      "bytes": 34777,
+      "bytes": 35001,
-      "lines": 797
+      "lines": 805
     },
     {
       "path": "database.py",
@@ -601,6 +601,11 @@
       "bytes": 9876,
       "lines": 224
     },
+    {
+      "path": "backend/data/providers/tushare_daily.py",
+      "bytes": 9539,
+      "lines": 241
+    },
     {
       "path": "backend/features/market/insights_themes.py",
       "bytes": 9348,
@@ -611,11 +616,6 @@
       "bytes": 9139,
       "lines": 199
     },
-    {
-      "path": "backend/data/providers/tushare_daily.py",
-      "bytes": 9076,
-      "lines": 232
-    },
     {
       "path": "backend/data/providers/tushare_dragon_tiger.py",
       "bytes": 9059,

tests/test_hel494_regressions.py

@@ -80,6 +80,50 @@ class LimitOverlayTests(unittest.TestCase):
         self.assertEqual(rows[0]["fd_amount"], 82000000)
         self.assertEqual(rows[0]["turnover_ratio"], 18.4)
 
+    def test_overlay_replaces_provisional_first_board_with_observed_streak(self) -> None:
+        mixin = DailyMarketMixin()
+        mixin._load_limit_lists = lambda trade_date: []
+        mixin.try_limit_pool = lambda trade_date: [
+            {"ts_code": "000737.SZ", "limit_times": 3}
+        ]
+
+        rows = mixin._overlay_board_fields(
+            [{"ts_code": "000737.SZ", "limit_times": 1, "limit_type": "U"}],
+            "20260909",
+        )
+
+        self.assertEqual(rows[0]["limit_times"], 3)
+
+    def test_daily_fallback_extends_yesterday_streak(self) -> None:
+        mixin = DailyMarketMixin()
+        mixin.query = lambda *args, **kwargs: []
+        mixin._load_limit_lists = lambda trade_date: []
+
+        rows = mixin._derive_limits(
+            "20260909",
+            [
+                {
+                    "ts_code": "000737.SZ",
+                    "trade_date": "20260909",
+                    "close": 11.0,
+                    "high": 11.0,
+                    "pct_chg": 10.0,
+                    "amount": 100000,
+                }
+            ],
+            price_limits=[
+                {"ts_code": "000737.SZ", "up_limit": 11.0, "down_limit": 9.0}
+            ],
+            basic_rows=[
+                {"ts_code": "000737.SZ", "name": "北方铜业", "industry": "有色"}
+            ],
+            previous_limit_rows=[
+                {"ts_code": "000737.SZ", "limit_times": 2}
+            ],
+        )
+
+        self.assertEqual(rows[0]["limit_times"], 3)
+
 
 class ShenwanRealtimeSourceTests(unittest.TestCase):
     def test_transport_refuses_rt_sw_k(self) -> None: