allow adjust_trade_position to return tuples in backtesting

freqtrade/optimize/backtesting.py

@@ -537,14 +537,22 @@ class Backtesting:
         min_stake = self.exchange.get_min_pair_stake_amount(trade.pair, current_rate, -0.1)
         max_stake = self.exchange.get_max_pair_stake_amount(trade.pair, current_rate)
         stake_available = self.wallets.get_available_stake_amount()
-        stake_amount = strategy_safe_wrapper(self.strategy.adjust_trade_position,
-                                             default_retval=None, supress_error=True)(
+        resp = strategy_safe_wrapper(self.strategy.adjust_trade_position,
+                                     default_retval=None, supress_error=True)(
             trade=trade,  # type: ignore[arg-type]
             current_time=current_time, current_rate=current_rate,
             current_profit=current_profit, min_stake=min_stake,
             max_stake=min(max_stake, stake_available),
             current_entry_rate=current_rate, current_exit_rate=current_rate,
             current_entry_profit=current_profit, current_exit_profit=current_profit)
+        order_tag = ''
+        if isinstance(resp, tuple):
+            if len(resp) >= 1:
+                stake_amount = resp[0]
+            if len(resp) > 1:
+                order_tag = resp[1] or ''
+        else:
+            stake_amount = resp
 
         # Check if we should increase our position
         if stake_amount is not None and stake_amount > 0.0:
@@ -569,7 +577,7 @@ class Backtesting:
             if min_stake and remaining != 0 and remaining < min_stake:
                 # Remaining stake is too low to be sold.
                 return trade
-            exit_ = ExitCheckTuple(ExitType.PARTIAL_EXIT)
+            exit_ = ExitCheckTuple(ExitType.PARTIAL_EXIT, order_tag)
             pos_trade = self._get_exit_for_signal(trade, row, exit_, current_time, amount)
             if pos_trade is not None:
                 order = pos_trade.orders[-1]

freqtrade/strategy/interface.py

@@ -511,7 +511,8 @@ class IStrategy(ABC, HyperStrategyMixin):
                               min_stake: Optional[float], max_stake: float,
                               current_entry_rate: float, current_exit_rate: float,
                               current_entry_profit: float, current_exit_profit: float,
-                              **kwargs) -> Optional[float]:
+                              **kwargs
+                              ) -> Union[Optional[float], Tuple[Optional[float], Optional[str]]]:
         """
         Custom trade adjustment logic, returning the stake amount that a trade should be
         increased or decreased.
@@ -537,6 +538,7 @@ class IStrategy(ABC, HyperStrategyMixin):
         :return float: Stake amount to adjust your trade,
                        Positive values to increase position, Negative values to decrease position.
                        Return None for no action.
+                       Optionally, return a tuple with a 2nd element with an order reason
         """
         return None