python type_error ai_generated true

RuntimeError: 依赖缓存键必须是可哈希的

RuntimeError: Dependency cache key must be hashable

ID: python/fastapi-runtimeerror-dependency-cache-key-must-be-hashable

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80%修复率
84%置信度
0证据数
2024-08-15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

使用可变对象（如列表或字典）作为 FastAPI 尝试缓存的依赖参数。

English

Using a mutable object (like a list or dict) as a dependency parameter that FastAPI tries to cache.

generic

解决方案

  1. 90% 成功率 Use immutable types like tuple instead of list. 
    from typing import Tuple
async def dependency(items: Tuple[int, ...] = (1, 2, 3)):
    return items
  2. 95% 成功率 Use Pydantic models for complex parameters. 
    from pydantic import BaseModel
class FilterParams(BaseModel):
    tags: list[str] = []

async def dependency(params: FilterParams):
    return params

无效尝试

常见但无效的做法:

  1. Using a list as a default value for a dependency. 80% 失败

    Lists are mutable and unhashable, causing caching issues.

  2. Using a dict as a query parameter. 70% 失败

    Query parameters must be hashable; dicts are not.