Don't claim 'possibly delisted' when Yahoo explains the missing data

Every YFPricesMissingError message speculates 'possibly delisted',
even when Yahoo's response carries an explicit reason that has nothing
to do with delisting, e.g. an intraday range outside the last 60 days.
That speculation has misled users for years (see #1713, #1797, #2044,
#2052). And when a ticker really is dead, Yahoo's quoted description
already says 'No data found, symbol may be delisted', making the
prefix redundant there too.

Add possibly_delisted=True parameter to YFTickerMissingError and
YFPricesMissingError (default keeps every other callsite unchanged)
and pass False in the one history() branch where Yahoo supplied an
error description, letting Yahoo's stated reason stand.

Adds an offline test of both message formats and a live test that a
range error no longer claims delisting.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: vignesh-nagarajan-vn

tests/test_prices.py

@@ -496,6 +496,31 @@ def test_30m_interval_error_mentions_requested_interval(self):
         self.assertIn("(30m ", msg)
         self.assertNotIn("(15m ", msg)
 
+    def test_prices_missing_error_delisted_prefix(self):
+        # Offline check of YFPricesMissingError message formats: the
+        # 'possibly delisted' speculation must be suppressible when the
+        # real cause of missing data is known.
+        from yfinance.exceptions import YFPricesMissingError
+        e = YFPricesMissingError("AAA", "(1d 2020-01-01 -> 2020-01-02)")
+        self.assertEqual(str(e), "$AAA: possibly delisted; no price data found (1d 2020-01-01 -> 2020-01-02)")
+        e = YFPricesMissingError("AAA", "(1d 2020-01-01 -> 2020-01-02)", possibly_delisted=False)
+        self.assertEqual(str(e), "$AAA: no price data found (1d 2020-01-01 -> 2020-01-02)")
+
+    def test_range_error_does_not_claim_delisting(self):
+        # A request Yahoo rejects with an explicit range error is not
+        # delisting evidence, so the message must not speculate 'possibly
+        # delisted'. When a ticker really is dead, Yahoo's quoted error
+        # text still communicates it.
+        from yfinance.exceptions import YFPricesMissingError
+        dat = yf.Ticker("SPY", session=self.session)
+        start_d = _dt.date.today() - _dt.timedelta(days=120)
+        end_d = start_d + _dt.timedelta(days=7)
+        with self.assertRaises(YFPricesMissingError) as cm:
+            dat.history(start=start_d, end=end_d, interval="30m", raise_errors=True)
+        msg = str(cm.exception)
+        self.assertNotIn("possibly delisted", msg)
+        self.assertIn("no price data found", msg)
+
 
 if __name__ == '__main__':
     unittest.main()

yfinance/exceptions.py

@@ -13,8 +13,15 @@ def __init__(self, method_name):
 
 
 class YFTickerMissingError(YFException):
-    def __init__(self, ticker, rationale):
-        super().__init__(f"${ticker}: possibly delisted; {rationale}")
+    """Expected ticker data is missing.
+
+    By default the message speculates the ticker is delisted, because Yahoo
+    rarely explains the absence. Pass possibly_delisted=False when the real
+    cause is known, so the message does not mislead.
+    """
+    def __init__(self, ticker, rationale, possibly_delisted=True):
+        prefix = "possibly delisted; " if possibly_delisted else ""
+        super().__init__(f"${ticker}: {prefix}{rationale}")
         self.rationale = rationale
         self.ticker = ticker
 
@@ -25,12 +32,17 @@ def __init__(self, ticker):
 
 
 class YFPricesMissingError(YFTickerMissingError):
-    def __init__(self, ticker, debug_info):
+    """Yahoo returned no price data for the requested range/interval.
+
+    possibly_delisted=False suppresses the delisting speculation, e.g. when
+    Yahoo's response contains an explicit reason for the missing data.
+    """
+    def __init__(self, ticker, debug_info, possibly_delisted=True):
         self.debug_info = debug_info
         if debug_info != '':
-            super().__init__(ticker, f"no price data found {debug_info}")
+            super().__init__(ticker, f"no price data found {debug_info}", possibly_delisted)
         else:
-            super().__init__(ticker, "no price data found")
+            super().__init__(ticker, "no price data found", possibly_delisted)
 
 
 class YFEarningsDateMissing(YFTickerMissingError):

yfinance/scrapers/history.py

@@ -282,7 +282,8 @@ def history(self, period=period_default, interval="1d",
                 # Yahoo's error names the fetched interval, which can differ from
                 # the user's request (e.g. 30m is fetched as 15m).
                 _price_data_debug += f' ({interval_user} resampled from {params["interval"]})'
-            _exception = YFPricesMissingError(self.ticker, _price_data_debug)
+            # Yahoo gave an explicit reason, so don't speculate about delisting.
+            _exception = YFPricesMissingError(self.ticker, _price_data_debug, possibly_delisted=False)
             fail = True
         elif "chart" not in data or not data["chart"] or data["chart"]["result"] is None or not data["chart"]["result"] or not data["chart"]["result"][0]["indicators"]["quote"][0]:
             _exception = YFPricesMissingError(self.ticker, _price_data_debug)