fix(HEL-494): 盘中双免费源故障切换并禁止问天假0覆盖

主源东财失败后自动改走腾讯行情，成功结果写入缓存；两源都失败时返回最近真实快照并标明延迟，不再显示假0。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

xiaobai-datahub/datahub/realtime_serve.py

@@ -11,6 +11,7 @@ import time
 from datetime import datetime
 from typing import Any
 
+from datahub.adapters.base import AdapterError
 from datahub.adapters.eastmoney import EastmoneyAdapter
 from datahub.adapters.tencent import TencentAdapter
 from datahub.codes import resolve_code
@@ -71,24 +72,32 @@ def fetch_market_quotes(db: HubDB) -> dict[str, Any]:
     cached = _read_cache(db, cache_key)
     if cached is not None:
         return cached
-    adapter = EastmoneyAdapter()
+    errors: list[str] = []
+    rows: list[dict[str, Any]] = []
+    source = ""
     try:
-        rows = adapter.fetch_market_quotes()
+        rows = EastmoneyAdapter().fetch_market_quotes()
         source = "eastmoney:clist"
     except Exception as exc:
-        raise RealtimeApiError("SOURCE_UNAVAILABLE", f"market quotes unavailable: {exc}") from exc
-    payload = _envelope(
-        rows,
-        {
-            "tier": "provisional",
-            "trade_date": yyyymmdd(now_shanghai()),
-            "source": source,
-            "stale": False,
-            "staleness_seconds": 0,
-            "published_at": isoformat(now_shanghai()),
-            "scope": "market",
-        },
-    )
+        errors.append(f"eastmoney:{exc}")
+        try:
+            listed = _listed_ts_codes(db)
+            if not listed:
+                raise AdapterError("no local stock master for tencent market snapshot")
+            rows = TencentAdapter().fetch_quotes(listed)
+            if len(rows) < 200:
+                raise AdapterError(f"Tencent market snapshot too small: {len(rows)}")
+            source = "tencent:qt"
+        except Exception as backup_exc:
+            errors.append(f"tencent:{backup_exc}")
+            recovered = _load_quotes_lkg(db, cache_key)
+            if recovered is not None:
+                return recovered
+            raise RealtimeApiError(
+                "SOURCE_UNAVAILABLE",
+                "market quotes unavailable: " + "；".join(errors),
+            ) from backup_exc
+    payload = _quote_payload(rows, source, scope="market")
     _write_cache(db, cache_key, payload, QUOTE_TTL, source)
     return payload
 
@@ -110,29 +119,98 @@ def fetch_quotes(db: HubDB, codes: list[str]) -> dict[str, Any]:
     cached = _read_cache(db, cache_key)
     if cached is not None:
         return cached
-    adapter = EastmoneyAdapter()
+    minimum = max(1, int(len(resolved) * 0.5))
+    errors: list[str] = []
+    rows: list[dict[str, Any]] = []
+    source = ""
     try:
-        rows: list[dict[str, Any]] = []
-        for index in range(0, len(resolved), QUOTE_BATCH):
-            rows.extend(adapter.fetch_quotes(resolved[index:index + QUOTE_BATCH]))
+        rows = _eastmoney_named_quotes(resolved)
+        if len(rows) < minimum:
+            raise AdapterError(f"Eastmoney named quotes too small: {len(rows)}/{len(resolved)}")
         source = "eastmoney:ulist"
     except Exception as exc:
-        raise RealtimeApiError("SOURCE_UNAVAILABLE", f"quotes unavailable: {exc}") from exc
-    payload = _envelope(
-        rows,
-        {
-            "tier": "provisional",
-            "trade_date": yyyymmdd(now_shanghai()),
-            "source": source,
-            "stale": False,
-            "staleness_seconds": 0,
-            "published_at": isoformat(now_shanghai()),
-        },
-    )
+        errors.append(f"eastmoney:{exc}")
+        try:
+            rows = TencentAdapter().fetch_quotes(resolved)
+            if len(rows) < minimum:
+                raise AdapterError(f"Tencent named quotes too small: {len(rows)}/{len(resolved)}")
+            source = "tencent:qt"
+        except Exception as backup_exc:
+            errors.append(f"tencent:{backup_exc}")
+            recovered = _load_quotes_lkg(db, cache_key)
+            if recovered is not None:
+                return recovered
+            raise RealtimeApiError(
+                "SOURCE_UNAVAILABLE",
+                "quotes unavailable: " + "；".join(errors),
+            ) from backup_exc
+    payload = _quote_payload(rows, source)
     _write_cache(db, cache_key, payload, QUOTE_TTL, source)
     return payload
 
 
+def _eastmoney_named_quotes(codes: list[str]) -> list[dict[str, Any]]:
+    adapter = EastmoneyAdapter()
+    rows: list[dict[str, Any]] = []
+    for index in range(0, len(codes), QUOTE_BATCH):
+        rows.extend(adapter.fetch_quotes(codes[index:index + QUOTE_BATCH]))
+    return rows
+
+
+def _listed_ts_codes(db: HubDB) -> list[str]:
+    try:
+        rows = db.fetchall(
+            "SELECT ts_code FROM stock_master WHERE list_status = 'L' ORDER BY ts_code"
+        )
+    except Exception:
+        return []
+    return [str(row.get("ts_code") or "") for row in rows if row.get("ts_code")]
+
+
+def _quote_payload(
+    rows: list[dict[str, Any]],
+    source: str,
+    scope: str = "",
+) -> dict[str, Any]:
+    meta: dict[str, Any] = {
+        "tier": "provisional",
+        "trade_date": yyyymmdd(now_shanghai()),
+        "source": source,
+        "stale": False,
+        "staleness_seconds": 0,
+        "published_at": isoformat(now_shanghai()),
+        "failover": source.startswith("tencent"),
+        "delay_notice": "",
+    }
+    if scope:
+        meta["scope"] = scope
+    return _envelope(rows, meta)
+
+
+def _load_quotes_lkg(db: HubDB, cache_key: str) -> dict[str, Any] | None:
+    store = LastKnownGood(db)
+    item = store.load(cache_key)
+    payload = item.get("payload") if item else None
+    if not isinstance(payload, dict):
+        return None
+    data = payload.get("data")
+    if not isinstance(data, list) or not data:
+        return None
+    stamped = dict(payload)
+    meta = dict(stamped.get("meta") or {})
+    stored = str((item or {}).get("stored_at") or "")
+    try:
+        age = max(0, int(time.time() - datetime.fromisoformat(stored).timestamp()))
+    except Exception:
+        age = QUOTE_TTL
+    meta["stale"] = True
+    meta["staleness_seconds"] = age
+    meta["delay_notice"] = f"主备免费行情均暂不可用，显示 {age} 秒前的真实快照"
+    meta["lkg_source"] = str((item or {}).get("source") or meta.get("source") or "")
+    stamped["meta"] = meta
+    return stamped
+
+
 def fetch_intraday(db: HubDB, code: str, date: str = "") -> dict[str, Any]:
     ts_code = resolve_code(db, code) or _guess_ts_code(code)
     if not ts_code: