From b2b19915e6e6180cd1602fc41a73d7f4428de91a Mon Sep 17 00:00:00 2001
From: Matthias <xmatthias@outlook.com>
Date: Wed, 12 Apr 2023 06:54:06 +0200
Subject: [PATCH] Limit enter_tag and exit_reason to their actual field lenght

closes #8486
---
 freqtrade/constants.py                |  2 +-
 freqtrade/persistence/trade_model.py  |  9 ++++++++-
 tests/persistence/test_persistence.py | 28 ++++++++++++++++++++++++++-
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/freqtrade/constants.py b/freqtrade/constants.py
index d83072064..2fcb957a3 100644
--- a/freqtrade/constants.py
+++ b/freqtrade/constants.py
@@ -64,7 +64,7 @@ USERPATH_FREQAIMODELS = 'freqaimodels'
 TELEGRAM_SETTING_OPTIONS = ['on', 'off', 'silent']
 WEBHOOK_FORMAT_OPTIONS = ['form', 'json', 'raw']
 FULL_DATAFRAME_THRESHOLD = 100
-CUSTOM_TAG_MAX_LENGTH = 64
+CUSTOM_TAG_MAX_LENGTH = 100
 
 ENV_VAR_PREFIX = 'FREQTRADE__'
 
diff --git a/freqtrade/persistence/trade_model.py b/freqtrade/persistence/trade_model.py
index a9d58f6ec..0572b45a6 100644
--- a/freqtrade/persistence/trade_model.py
+++ b/freqtrade/persistence/trade_model.py
@@ -9,7 +9,7 @@ from typing import Any, ClassVar, Dict, List, Optional, Sequence, cast
 
 from sqlalchemy import (Enum, Float, ForeignKey, Integer, ScalarResult, Select, String,
                         UniqueConstraint, desc, func, select)
-from sqlalchemy.orm import Mapped, lazyload, mapped_column, relationship
+from sqlalchemy.orm import Mapped, lazyload, mapped_column, relationship, validates
 
 from freqtrade.constants import (CUSTOM_TAG_MAX_LENGTH, DATETIME_PRINT_FORMAT, MATH_CLOSE_PREC,
                                  NON_OPEN_EXCHANGE_STATES, BuySell, LongShort)
@@ -1295,6 +1295,13 @@ class Trade(ModelBase, LocalTrade):
         self.realized_profit = 0
         self.recalc_open_trade_value()
 
+    @validates('enter_tag', 'exit_reason')
+    def validate_string_len(self, key, value):
+        max_len = getattr(self.__class__, key).prop.columns[0].type.length
+        if value and len(value) > max_len:
+            return value[:max_len]
+        return value
+
     def delete(self) -> None:
 
         for order in self.orders:
diff --git a/tests/persistence/test_persistence.py b/tests/persistence/test_persistence.py
index 23ec6d4fb..948973ed5 100644
--- a/tests/persistence/test_persistence.py
+++ b/tests/persistence/test_persistence.py
@@ -6,7 +6,7 @@ import arrow
 import pytest
 from sqlalchemy import select
 
-from freqtrade.constants import DATETIME_PRINT_FORMAT
+from freqtrade.constants import CUSTOM_TAG_MAX_LENGTH, DATETIME_PRINT_FORMAT
 from freqtrade.enums import TradingMode
 from freqtrade.exceptions import DependencyException
 from freqtrade.persistence import LocalTrade, Order, Trade, init_db
@@ -2037,6 +2037,7 @@ def test_Trade_object_idem():
         'get_mix_tag_performance',
         'get_trading_volume',
         'from_json',
+        'validate_string_len',
     )
     EXCLUDES2 = ('trades', 'trades_open', 'bt_trades_open_pp', 'bt_open_open_trade_count',
                  'total_profit')
@@ -2055,6 +2056,31 @@ def test_Trade_object_idem():
             assert item in trade
 
 
+@pytest.mark.usefixtures("init_persistence")
+def test_trade_truncates_string_fields():
+    trade = Trade(
+        pair='ADA/USDT',
+        stake_amount=20.0,
+        amount=30.0,
+        open_rate=2.0,
+        open_date=datetime.utcnow() - timedelta(minutes=20),
+        fee_open=0.001,
+        fee_close=0.001,
+        exchange='binance',
+        leverage=1.0,
+        trading_mode='futures',
+        enter_tag='a' * CUSTOM_TAG_MAX_LENGTH * 2,
+        exit_reason='b' * CUSTOM_TAG_MAX_LENGTH * 2,
+    )
+    Trade.session.add(trade)
+    Trade.commit()
+
+    trade1 = Trade.session.scalars(select(Trade)).first()
+
+    assert trade1.enter_tag == 'a' * CUSTOM_TAG_MAX_LENGTH
+    assert trade1.exit_reason == 'b' * CUSTOM_TAG_MAX_LENGTH
+
+
 def test_recalc_trade_from_orders(fee):
 
     o1_amount = 100