fix(data): reject stale yfinance OHLCV instead of reporting wrong prices

yfinance intermittently returns a year-old partial frame (e.g. June 2025 rows
for a June 2026 request) that still has rows and a Close, so it passed the
empty-check and silently fed a wrong close price and indicators into the report
(#1021). Add a freshness guard that rejects a frame whose latest row is far
older than the requested date, on both the raw OHLCV path and the indicator
path. It raises the existing NoMarketDataError with a stale-specific detail, so
the vendor router's try-next-vendor and single unavailable-signal handling apply
unchanged; the sentinel now surfaces that detail so the agent reports the
specific reason rather than fabricating a value.

tradingagents/dataflows/y_finance.py

@@ -1,11 +1,19 @@
-from typing import Annotated
 from datetime import datetime
-from dateutil.relativedelta import relativedelta
+from typing import Annotated
+
 import pandas as pd
 import yfinance as yf
-import os
-from .stockstats_utils import StockstatsUtils, _clean_dataframe, yf_retry, load_ohlcv, filter_financials_by_date
-from .symbol_utils import normalize_symbol, NoMarketDataError
+from dateutil.relativedelta import relativedelta
+
+from .stockstats_utils import (
+    StockstatsUtils,
+    _assert_ohlcv_not_stale,
+    filter_financials_by_date,
+    load_ohlcv,
+    yf_retry,
+)
+from .symbol_utils import NoMarketDataError, normalize_symbol
+
 
 def get_YFin_data_online(
     symbol: Annotated[str, "ticker symbol of the company"],
@@ -38,6 +46,11 @@ def get_YFin_data_online(
     if data.index.tz is not None:
         data.index = data.index.tz_localize(None)
 
+    # Reject a stale frame (e.g. a year-old partial response) before it is
+    # formatted into the report. Raises NoMarketDataError, which the router
+    # turns into one clear unavailable signal (#1021).
+    _assert_ohlcv_not_stale(data, end_date, symbol, canonical)
+
     # Round numerical values to 2 decimal places for cleaner display
     numeric_columns = ["Open", "High", "Low", "Close", "Adj Close"]
     for col in numeric_columns:
@@ -150,23 +163,23 @@ def get_stock_stats_indicators_window(
     # Optimized: Get stock data once and calculate indicators for all dates
     try:
         indicator_data = _get_stock_stats_bulk(symbol, indicator, curr_date)
-        
+
         # Generate the date range we need
         current_dt = curr_date_dt
         date_values = []
-        
+
         while current_dt >= before:
             date_str = current_dt.strftime('%Y-%m-%d')
-            
+
             # Look up the indicator value for this date
             if date_str in indicator_data:
                 indicator_value = indicator_data[date_str]
             else:
                 indicator_value = "N/A: Not a trading day (weekend or holiday)"
-            
+
             date_values.append((date_str, indicator_value))
             current_dt = current_dt - relativedelta(days=1)
-        
+
         # Build the result string
         ind_string = ""
         for date_str, value in date_values:
@@ -211,22 +224,22 @@ def _get_stock_stats_bulk(
     data = load_ohlcv(symbol, curr_date)
     df = wrap(data)
     df["Date"] = df["Date"].dt.strftime("%Y-%m-%d")
-    
+
     # Calculate the indicator for all rows at once
     df[indicator]  # This triggers stockstats to calculate the indicator
-    
+
     # Create a dictionary mapping date strings to indicator values
     result_dict = {}
     for _, row in df.iterrows():
         date_str = row["Date"]
         indicator_value = row[indicator]
-        
+
         # Handle NaN/None values
         if pd.isna(indicator_value):
             result_dict[date_str] = "N/A"
         else:
             result_dict[date_str] = str(indicator_value)
-    
+
     return result_dict
 
 
@@ -450,8 +463,8 @@ def get_insider_transactions(
         # Add header information
         header = f"# Insider Transactions data for {canonical}\n"
         header += f"# Data retrieved on: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}\n\n"
-        
+
         return header + csv_string
-        
+
     except Exception as e:
-        return f"Error retrieving insider transactions for {ticker}: {str(e)}"
+        return f"Error retrieving insider transactions for {ticker}: {str(e)}"