# 错误：ResolutionImpossible：ResolutionTooDeep：回溯过深（2000000 次迭代）

- **ID:** `python/pip-dependency-resolution-too-deep`
- **领域:** python
- **类别:** install_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

pip 解析器在尝试满足大型、约束严格的依赖图时达到了回溯上限。通常由许多包之间过于宽泛或冲突的版本固定引起。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 3.8 | active | — | — |
| 3.9 | active | — | — |
| 3.10 | active | — | — |
| 3.11 | active | — | — |
| 3.12 | active | — | — |

## 解决方案

1. **** (88% 成功率)
   ```
   pip install pip-tools
pip-compile --resolver=backtracking requirements.in
pip install -r requirements.txt
   ```
2. **** (82% 成功率)
   ```
   pip install -c constraints.txt core-deps
pip install -c constraints.txt app-deps
   ```

## 无效尝试

- **** — Legacy resolver picks versions greedily and produces an inconsistent environment that breaks at runtime. (85% 失败率)
- **** — Allowing pre-releases expands the search space and worsens backtracking. (80% 失败率)