cointrader/docs/plans/2026-03-19-critical-bugfixes.md

Critical Bugfixes Implementation Plan

For agentic workers: REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (- [ ]) syntax for tracking.

Goal: Fix 4 critical bugs identified in code review (C5, C1, C3, C8)

Architecture: Direct fixes to backtester.py, bot.py, main.py — no new files needed

Tech Stack: Python asyncio, signal handling

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Task 1: C5 — Backtester double fee deduction + atr≤0 fee leak

Files:

• Modify: src/backtester.py:494-501

• Remove self.balance -= entry_fee at L496. The fee is already deducted in _close_position via net_pnl = gross_pnl - entry_fee - exit_fee.

• This also fixes the atr≤0 early return bug — since balance is no longer modified before ATR check, early return doesn't leak fees.

Task 2: C1 — SL/TP atomicity with retry and emergency close

Files:

• Modify: src/bot.py:461-475

• Wrap SL/TP placement in _place_sl_tp_with_retry() with 3 retries and 1s backoff

• Track sl_placed and tp_placed independently to avoid re-placing successful orders

• On final failure, call _emergency_close() which market-closes the position and notifies via Discord

• _emergency_close also handles its own failure with critical log + Discord alert

Task 3: C3 — PnL double recording race condition

Files:

• Modify: src/bot.py (init, _on_position_closed, _position_monitor)

• Add self._close_lock = asyncio.Lock() to __init__

• Wrap _on_position_closed body with async with self._close_lock

• Wrap SYNC path in _position_monitor with async with self._close_lock

• Add double-check after lock acquisition in monitor (callback may have already processed)

Task 4: C8 — Graceful shutdown with signal handler

Files:

• Modify: main.py

• Add signal.SIGTERM and signal.SIGINT handlers via loop.add_signal_handler()

• Use asyncio.Event + asyncio.wait(FIRST_COMPLETED) pattern

• _graceful_shutdown(): cancel all open orders per bot (with 5s timeout), then cancel tasks

• Log shutdown progress for each symbol

Verification

• All 138 existing tests pass (0 failures)