feature(addLimitsMaxPeriod): limit start_date to its minimal allowed value

tests/prices.py

@@ -228,6 +228,81 @@ def test_monthlyWithEvents(self):
                 print("{}-without-events missing these dates: {}".format(tkr, missing_from_df2))
                 raise
 
+    def test_min_start_date_if_end_none(self):
+        tkrs = ["BHP.AX", "BHP.L", "BHP"]
+        intervals = ["1m", "2m", "60m", "90m", "1h"]
+
+        end = None
+
+        for tkr in tkrs:
+            dat = yf.Ticker(tkr, session=self.session)
+            for interval in intervals:
+                # First test minimum start is valid (not too old/low)
+                try:
+                    df1 = dat.history(period="max", interval=interval, raise_errors=True)
+                except Exception as e:
+                    if "days worth of" in str(e) and "granularity" in str(e):
+                        raise Exception(f"Minimum start is too old ({tkr} @ {interval})")
+                    else:
+                        raise
+                dt0 = df1.index[0]
+
+                # Next test if minimum start is too recent (high)
+                try:
+                    df2 = dat.history(start=dt0-_dt.timedelta(days=1), interval=interval, raise_errors=True)
+                except Exception as e:
+                    if "days worth of" in str(e) and "granularity" in str(e):
+                        # Fail = good!
+                        pass
+                    elif "requested range must be within the last" in str(e):
+                        # Fail = good!
+                        pass
+                    else:
+                        raise
+                else:
+                    if df2.index[0].date() < dt0.date():
+                        # 2nd request fetched more data so minimum could be older
+                        raise Exception(f"Minimum start is too conservative ({tkr} @ {interval})")
+
+    def test_min_start_date_if_end_last_week(self):
+        # tkrs = ["BHP.AX", "BHP.L", "BHP"]
+        # intervals = ["1m", "2m", "60m", "90m", "1h"]
+        tkrs = ["BHP.L"]
+        intervals = ["1m"]
+
+        end = _dt.datetime.now() - _dt.timedelta(days=7)
+
+        for tkr in tkrs:
+            dat = yf.Ticker(tkr, session=self.session)
+            for interval in intervals:
+                # First test minimum start is valid (not too old/low)
+                try:
+                    df1 = dat.history(period="max", end=end, interval=interval, raise_errors=True)
+                except Exception as e:
+                    if "days worth of" in str(e) and "granularity" in str(e):
+                        raise Exception(f"Minimum start is too old ({tkr} @ {interval})")
+                    else:
+                        raise
+                dt0 = df1.index[0]
+
+                # Next test if minimum start is too recent (high)
+                try:
+                    df2 = dat.history(start=dt0-_dt.timedelta(days=1), end=end, interval=interval, raise_errors=True)
+                except Exception as e:
+                    if "days worth of" in str(e) and "granularity" in str(e):
+                        # Fail = good!
+                        pass
+                    elif "requested range must be within the last" in str(e):
+                        # Fail = good!
+                        pass
+                    else:
+                        raise
+                else:
+                    if df2.index[0].date() < dt0.date():
+                        # 2nd request fetched more data so minimum could be older
+                        raise Exception(f"Minimum start is too conservative ({tkr} @ {interval})")
+
+
     def test_tz_dst_ambiguous(self):
         # Reproduce issue #1100
 

yfinance/base.py

@@ -152,8 +152,13 @@ def history(self, period="1mo", interval="1d",
             else:
                 end = utils._parse_user_dt(end, tz)
             if start is None:
-                if interval == "1m":
-                    start = end - 604800  # Subtract 7 days
+                start_limits = {"1m": 30, "2m": 60, "5m": 60, "15m": 60, "30m": 60, "60m": 60, "90m": 60, "1h": 730}
+                range_limits = {"1m": 7,  "2m": 60, "5m": 60, "15m": 60, "30m": 60, "60m": 60, "90m": 60, "1h": 730}
+                if interval in start_limits:
+                    start = end - int(range_limits[interval] * 86400)
+                    start_min = int(_time.time()) - int(start_limits[interval] * 86400)
+                    start = max(start, start_min)
+                    start += 5  # Allow 5 seconds for Yahoo to process request
                 else:
                     _UNIX_TIMESTAMP_1900 = -2208994789
                     start = _UNIX_TIMESTAMP_1900