python runtime_error ai_generated true

对象 '<User at 0x...>' 正在被合并到会话中，但相同的实例已存在

sqlalchemy.orm.exc.ConcurrentModificationError: Object '<User at 0x...>' is being merged into a Session but the same instance is already present

ID: python/sqlalchemy-orm-exc-concurrent-modification-error

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80%修复率
82%置信度
0证据数
2024-11-10首次发现

版本兼容性

版本状态引入弃用备注
3.x active — — —

根因分析

尝试合并一个已被同一会话跟踪的 ORM 实例，导致冲突。

English

Attempting to merge an ORM instance that is already tracked by the same session, causing a conflict.

generic

解决方案

  1. 80% 成功率 Check session identity map 
    Check if the instance is already in the session using session.is_modified() or track identities manually before merging.
  2. 90% 成功率 Merge with fresh instance 
    Use session.merge() with a new instance that has the same primary key, ensuring the session does not already contain it.

无效尝试

常见但无效的做法:

  1. Using add() instead of merge() 70% 失败

  2. Expunging the instance first 50% 失败