python runtime_error ai_generated true

ERROR at teardown of test_create_user File "tests/conftest.py", line 40, in db_session session.rollback() sqlalchemy.exc.PendingRollbackError: 由于 flush 期间之前的异常，此 Session 的事务已被回滚。

ERROR at teardown of test_create_user File "tests/conftest.py", line 40, in db_session session.rollback() sqlalchemy.exc.PendingRollbackError: This Session's transaction has been rolled back due to a previous exception during flush.

ID: python/pytest-teardown-error-masked

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80%修复率

82%置信度

0证据数

2024-09-14首次发现

版本兼容性

版本	状态	引入	弃用	备注
2.0	active	—	—	—

根因分析

测试使 SQLAlchemy session 处于失败状态（flush 期间未处理异常）；fixture 清理时对已失效的 session 调用 rollback/close，产生 teardown ERROR 掩盖了原始失败。

English

The test left the SQLAlchemy session in a failed state (unhandled exception during flush); the fixture teardown then calls rollback/close on a session that is already invalid, producing a teardown ERROR that masks the original failure.

generic

解决方案

90% 成功率

Use a nested transaction + savepoint pattern and always roll back cleanly:
@pytest.fixture
def db_session(engine):
    conn = engine.connect()
    trans = conn.begin()
    session = Session(bind=conn)
    try:
        yield session
    finally:
        session.close()
        trans.rollback()
        conn.close()

85% 成功率

Or use `session.begin_nested()` and explicitly rollback the savepoint:
@pytest.fixture
def db_session(engine):
    session = Session(bind=engine)
    session.begin_nested()
    yield session
    session.rollback()
    session.close()

无效尝试

常见但无效的做法:

85% 失败
Hides the real error and leaves the session dirty, cascading failures into later tests.
70% 失败
Does not clear the failed transaction state; rollback still raises.