From c1e938ccda226dd5f558fd91aea51b046da058b8 Mon Sep 17 00:00:00 2001
From: Matthias <xmatthias@outlook.com>
Date: Fri, 21 Jun 2024 14:01:25 +0200
Subject: [PATCH] Add "BacktestnigSupport" method to pairlists

---
 freqtrade/plugins/pairlist/IPairList.py | 13 +++++++++
 freqtrade/plugins/pairlistmanager.py    | 38 ++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/freqtrade/plugins/pairlist/IPairList.py b/freqtrade/plugins/pairlist/IPairList.py
index a2e70e649..c3d1a10ad 100644
--- a/freqtrade/plugins/pairlist/IPairList.py
+++ b/freqtrade/plugins/pairlist/IPairList.py
@@ -5,6 +5,7 @@ PairList Handler base class
 import logging
 from abc import ABC, abstractmethod
 from copy import deepcopy
+from enum import Enum
 from typing import Any, Dict, List, Literal, Optional, TypedDict, Union
 
 from freqtrade.constants import Config
@@ -51,8 +52,20 @@ PairlistParameter = Union[
 ]
 
 
+class SupportsBacktesting(str, Enum):
+    """
+    Enum to indicate if a Pairlist Handler supports backtesting.
+    """
+
+    YES = "yes"
+    NO = "no"
+    NO_ACTION = "no_action"
+    TODAYS_DATA = "todays_data"
+
+
 class IPairList(LoggingMixin, ABC):
     is_pairlist_generator = False
+    supports_backtesting: SupportsBacktesting = SupportsBacktesting.NO
 
     def __init__(
         self,
diff --git a/freqtrade/plugins/pairlistmanager.py b/freqtrade/plugins/pairlistmanager.py
index a6afd5e64..30b3d74f8 100644
--- a/freqtrade/plugins/pairlistmanager.py
+++ b/freqtrade/plugins/pairlistmanager.py
@@ -11,10 +11,11 @@ from cachetools import TTLCache, cached
 from freqtrade.constants import Config, ListPairsWithTimeframes
 from freqtrade.data.dataprovider import DataProvider
 from freqtrade.enums import CandleType
+from freqtrade.enums.runmode import RunMode
 from freqtrade.exceptions import OperationalException
 from freqtrade.exchange.types import Tickers
 from freqtrade.mixins import LoggingMixin
-from freqtrade.plugins.pairlist.IPairList import IPairList
+from freqtrade.plugins.pairlist.IPairList import IPairList, SupportsBacktesting
 from freqtrade.plugins.pairlist.pairlist_helpers import expand_pairlist
 from freqtrade.resolvers import PairListResolver
 
@@ -57,9 +58,44 @@ class PairListManager(LoggingMixin):
                 f"{invalid}."
             )
 
+        self._check_backtest()
+
         refresh_period = config.get("pairlist_refresh_period", 3600)
         LoggingMixin.__init__(self, logger, refresh_period)
 
+    def _check_backtest(self) -> None:
+        if self._config["runmode"] not in (RunMode.BACKTEST, RunMode.EDGE, RunMode.HYPEROPT):
+            return
+
+        pairlist_errors: List[str] = []
+        noaction_pairlists: List[str] = []
+        biased_pairlists: List[str] = []
+        for pairlist_handler in self._pairlist_handlers:
+            if pairlist_handler.supports_backtesting == SupportsBacktesting.NO:
+                pairlist_errors.append(pairlist_handler.name)
+            if pairlist_handler.supports_backtesting == SupportsBacktesting.NO_ACTION:
+                noaction_pairlists.append(pairlist_handler.name)
+            if pairlist_handler.supports_backtesting == SupportsBacktesting.TODAYS_DATA:
+                biased_pairlists.append(pairlist_handler.name)
+
+        if noaction_pairlists:
+            logger.warning(
+                f"Pairlist Handlers {', '.join(noaction_pairlists)} do not generate "
+                "any changes during backtesting. While it's safe to leave them enabled, they will "
+                "not behave like in dry/live modes. "
+            )
+
+        if biased_pairlists:
+            logger.warning(
+                f"Pairlist Handlers {', '.join(biased_pairlists)} will introduce a lookahead bias "
+                "to your backtest results, as they use today's data - which inheritly suffers from "
+                "'winner bias'."
+            )
+        if pairlist_errors:
+            raise OperationalException(
+                f"Pairlist Handlers {', '.join(pairlist_errors)} do not support backtesting."
+            )
+
     @property
     def whitelist(self) -> List[str]:
         """The current whitelist"""