Warn when using restricted pairs

As noted in https://github.com/ccxt/ccxt/issues/5624, there is currently
no way to detect if a user is impacted by this or not prior to creating
a order.

freqtrade/exchange/exchange.py

@@ -260,7 +260,7 @@ class Exchange(object):
 
         if not self.markets:
             logger.warning('Unable to validate pairs (assuming they are correct).')
-        #     return
+            return
 
         for pair in pairs:
             # Note: ccxt has BaseCurrency/QuoteCurrency format for pairs
@@ -269,6 +269,12 @@ class Exchange(object):
                 raise OperationalException(
                     f'Pair {pair} is not available on {self.name}. '
                     f'Please remove {pair} from your whitelist.')
+            elif self.markets[pair].get('info', {}).get('IsRestricted', False):
+                # Warn users about restricted pairs in whitelist.
+                # We cannot determine reliably if Users are affected.
+                logger.warning(f"Pair {pair} is restricted for some users on this exchange."
+                               f"Please check if you are impacted by this restriction "
+                               f"on the exchange and eventually remove {pair} from your whitelist.")
 
     def get_valid_pair_combination(self, curr_1, curr_2) -> str:
         """

freqtrade/tests/conftest.py

@@ -304,7 +304,7 @@ def markets():
                     'max': 500000,
                 },
             },
-            'info': '',
+            'info': {},
         },
         'TKN/BTC': {
             'id': 'tknbtc',
@@ -329,7 +329,7 @@ def markets():
                     'max': 500000,
                 },
             },
-            'info': '',
+            'info': {},
         },
         'BLK/BTC': {
             'id': 'blkbtc',
@@ -354,7 +354,7 @@ def markets():
                     'max': 500000,
                 },
             },
-            'info': '',
+            'info': {},
         },
         'LTC/BTC': {
             'id': 'ltcbtc',
@@ -379,7 +379,7 @@ def markets():
                     'max': 500000,
                 },
             },
-            'info': '',
+            'info': {},
         },
         'XRP/BTC': {
             'id': 'xrpbtc',
@@ -404,7 +404,7 @@ def markets():
                     'max': 500000,
                 },
             },
-            'info': '',
+            'info': {},
         },
         'NEO/BTC': {
             'id': 'neobtc',
@@ -429,7 +429,7 @@ def markets():
                     'max': 500000,
                 },
             },
-            'info': '',
+            'info': {},
         },
         'BTT/BTC': {
             'id': 'BTTBTC',
@@ -457,7 +457,7 @@ def markets():
                     'max': None
                 }
             },
-            'info': "",
+            'info': {},
         },
         'ETH/USDT': {
             'id': 'USDT-ETH',
@@ -479,7 +479,7 @@ def markets():
                 }
             },
             'active': True,
-            'info': ""
+            'info': {},
         },
         'LTC/USDT': {
             'id': 'USDT-LTC',
@@ -501,7 +501,7 @@ def markets():
                     'max': None
                 }
             },
-            'info': ""
+            'info': {},
         }
     }
 

freqtrade/tests/exchange/test_exchange.py

@@ -318,7 +318,7 @@ def test__reload_markets_exception(default_conf, mocker, caplog):
 def test_validate_pairs(default_conf, mocker):  # test exchange.validate_pairs directly
     api_mock = MagicMock()
     type(api_mock).markets = PropertyMock(return_value={
-        'ETH/BTC': '', 'LTC/BTC': '', 'XRP/BTC': '', 'NEO/BTC': ''
+        'ETH/BTC': {}, 'LTC/BTC': {}, 'XRP/BTC': {}, 'NEO/BTC': {}
     })
     id_mock = PropertyMock(return_value='test_exchange')
     type(api_mock).id = id_mock
@@ -332,7 +332,7 @@ def test_validate_pairs(default_conf, mocker):  # test exchange.validate_pairs d
 def test_validate_pairs_not_available(default_conf, mocker):
     api_mock = MagicMock()
     type(api_mock).markets = PropertyMock(return_value={
-        'XRP/BTC': 'inactive'
+        'XRP/BTC': {'inactive'}
     })
     mocker.patch('freqtrade.exchange.Exchange._init_ccxt', MagicMock(return_value=api_mock))
     mocker.patch('freqtrade.exchange.Exchange.validate_timeframes', MagicMock())
@@ -361,6 +361,23 @@ def test_validate_pairs_exception(default_conf, mocker, caplog):
                    caplog.record_tuples)
 
 
+def test_validate_pairs_restricted(default_conf, mocker, caplog):
+    api_mock = MagicMock()
+    type(api_mock).markets = PropertyMock(return_value={
+        'ETH/BTC': {}, 'LTC/BTC': {}, 'NEO/BTC': {},
+        'XRP/BTC': {'info': {'IsRestricted': True}}
+    })
+    mocker.patch('freqtrade.exchange.Exchange._init_ccxt', MagicMock(return_value=api_mock))
+    mocker.patch('freqtrade.exchange.Exchange.validate_timeframes', MagicMock())
+    mocker.patch('freqtrade.exchange.Exchange._load_async_markets', MagicMock())
+
+    Exchange(default_conf)
+    assert log_has(f"Pair XRP/BTC is restricted for some users on this exchange."
+                   f"Please check if you are impacted by this restriction "
+                   f"on the exchange and eventually remove XRP/BTC from your whitelist.",
+                   caplog.record_tuples)
+
+
 def test_validate_timeframes(default_conf, mocker):
     default_conf["ticker_interval"] = "5m"
     api_mock = MagicMock()