python runtime_error ai_generated partial

pydantic_core._pydantic_core.ValidationError: 1 个验证错误，递归深度超过 Python 最大限制

pydantic_core._pydantic_core.ValidationError: 1 validation error for Node children.0.children.0 RecursionError: maximum recursion depth exceeded while calling a Python object

ID: python/pydantic-recursion-error-self-referential

其他格式: JSON · Markdown 中文 · English
80%修复率
82%置信度
0证据数
2025-01-19首次发现

版本兼容性

版本状态引入弃用备注
2.x active — — —

根因分析

自引用 Pydantic 模型（树/图）接收到循环数据结构，导致验证时无限递归。Pydantic 对普通嵌套模型没有内置的循环检测。

English

A self-referential Pydantic model (tree/graph) was given a cyclic data structure, causing infinite recursion during validation. Pydantic has no built-in cycle detection for plain nested models.

generic

解决方案

  1. 85% 成功率 
    def break_cycles(obj, seen=None):
    seen = seen or set()
    if id(obj) in seen:
        return None
    seen.add(id(obj))
    if isinstance(obj, dict):
        return {k: break_cycles(v, seen) for k, v in obj.items()}
    if isinstance(obj, list):
        return [break_cycles(v, seen) for v in obj]
    return obj

Node.model_validate(break_cycles(raw))
  2. 70% 成功率 
    from pydantic import BaseModel, field_validator

class Node(BaseModel):
    name: str
    children: list['Node'] = []

    @field_validator('children')
    @classmethod
    def limit_depth(cls, v):
        if len(v) > 100:
            raise ValueError('tree too deep')
        return v

无效尝试

常见但无效的做法:

  1. 80% 失败

    This only defers the crash; a truly cyclic structure will still exhaust memory and eventually segfault the interpreter.

  2. 90% 失败

    arbitrary_types_allowed permits non-Pydantic types, it does not detect or prevent cyclic references.