python config_error ai_generated true

ScopeMismatch: 你尝试以会话级请求对象访问函数级 fixture 'tmp_path'，涉及的工厂

ScopeMismatch: You tried to access the function scoped fixture 'tmp_path' with a session scoped request object, involved factories

ID: python/pytest-session-scoped-fixture-with-function-scope

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80%修复率
88%置信度
0证据数
2024-05-21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

会话级 fixture 依赖函数级 fixture（如 tmp_path 或 monkeypatch），pytest 禁止此行为，因为窄作用域 fixture 无法比宽作用域 fixture 存活更久。

English

A session-scoped fixture depends on a function-scoped fixture (like tmp_path or monkeypatch), which pytest forbids because the narrower fixture cannot outlive the wider one.

generic

解决方案

  1. 95% 成功率 
    @pytest.fixture(scope='session')
def data_dir(tmp_path_factory):
    d = tmp_path_factory.mktemp('data')
    (d / 'file.txt').write_text('hi')
    return d
  2. 85% 成功率 
    @pytest.fixture(scope='session')
def cache():
    return {}

@pytest.fixture
def resource(cache, tmp_path):
    if 'r' not in cache:
        cache['r'] = build(tmp_path)
    yield cache['r']

无效尝试

常见但无效的做法:

  1. 50% 失败

    Defeats the purpose of sharing expensive setup; tests slow down dramatically.

  2. 85% 失败

    Raises the same ScopeMismatch at runtime; getfixturevalue does not change scopes.