Expanding on the default unpickling behavior of objects that do not implement __setstate__
還沒有人認領這個 Issue。
- 主要語言
- Python
- 星號
- 77.2k
- 分支
- 36k
- 平均合併
- 1 天 9 小時
- 30 天內合併 PR
- 558
描述
Documentation
I'm about to open a PR for it myself but I wanted to also open a related issue (just in case there are any objections)
Ever since Python 3.11, __getstate__'s default implementation has been added to object. With that change, the section explaining __getstate__ was expanded to also explain the default implementation in regards to slotted objects and the fact that their default state is a tuple of dicts (1 for the slotted dict and 1 optional dynamic dict) .
With this change, the user is now aware of the new concept of the "slotted state" and therefore should be aware of how it is handled when __setstate__ was not implemented. The current documentation states that the user may choose to implement __getstate__ and not __setstate__ so long as the returned state was a dict.
This needs to be updated to explain it also accepts tuples of the former format. Moreover, it should be updated to explain how do these 2 dicts differ in their setting behavior:
- The dynamic dict MUST be set using direct edit of the instance's
__dict__(in order to not activate__setattr__which is very important, especially on immutable instances that will throw an exception on such calls). This is behavior is similar to pure dict states (and should probably be documented as well) - The slotted dict MUST be set using calls to setattr (since they by definition do not exist on the instance
__dict__and therefore cannot be directly edited. Also we want to avoid accidentally a duplicate value on that dict)
Explaining this behavior will be more detailed and helpful than the current note that vaguely states:
At unpickling time, some methods like __getattr__(), __getattribute__(), or __setattr__() may be called upon the instance.
In case those methods rely on some internal invariant being true, the type should implement __new__() to establish such an invariant,
as __init__() is not called when unpickling an instance.
Explaining it will also prevent users from mistakenly relying on __setattr__ when they shouldn't. This will also prevents libraries like jsonpickle from incorrectly implementing their unpickling behavior to always use setattr (which causes bugs that arise from discrepancies with the default pickle library.
貢獻指南
從這裡開始
- 先讀完整個 Issue,再讀專案的貢獻指南。
- 在 Issue 下留言說明你要接手 —— 這能避免兩個人做同樣的事。
- Fork 儲存庫,在一個分支上完成修改。
- 送出 Pull Request,並在描述裡引用這個 Issue 編號。
研究方向
從解釋 getstate、setstate 以及反序列化行為的文件部分開始。明確說明接受元組狀態,區分針對動態狀態的直接 dict 更新與針對插槽狀態的 setattr 呼叫,並在不依賴現有模糊註解的情況下說明相關行為。
由索引模型根據 Issue 內容生成。
評估
- 技術堆疊
- python
- 領域
- documentation
- Issue 類型
- 文件
- 難度
- 3/5
- 預估耗時
- 1-2 天
- 活躍度
- 停滯
- 描述清晰度
- 基本清楚
- 新手友好度
- 38/100