python runtime_error ai_generated true

AssertionError: assert 1 == 2 # 使用 -p no:xdist 时通过，使用 -n auto 时失败

AssertionError: assert 1 == 2 # passes with -p no:xdist, fails with -n auto

ID: python/pytest-xdist-shared-state

其他格式: JSON · Markdown 中文 · English

80%修复率

85%置信度

0证据数

2024-10-21首次发现

版本兼容性

版本	状态	引入	弃用	备注
7.x	active	—	—	—
8.x	active	—	—	—

根因分析

测试共享全局状态（模块级缓存、单例、文件），在串行下安全，但在 pytest-xdist 的多个 worker 进程下产生竞态或持久化。

English

Tests share global state (module-level caches, singletons, files) that is safe serially but races or persists across worker processes under pytest-xdist.

generic

解决方案

90% 成功率

@pytest.fixture(autouse=True)
def reset_state():
    myapp.cache.clear()
    yield
    myapp.cache.clear()

88% 成功率

def test_db(tmp_path, worker_id):
    if worker_id == 'master':
        db = tmp_path / 'db.sqlite'
    else:
        db = tmp_path / f'db_{worker_id}.sqlite'
    ...

无效尝试

常见但无效的做法:

70% 失败
Masks the race condition; reruns may pass by luck and hide real bugs, and flaky plugin adds overhead.
95% 失败
More workers means more contention, making the race more likely, not less.
85% 失败
Slows tests and does not eliminate the race; still fails intermittently on slow CI machines.