Add typed attribute to third party class.

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難度
5/5
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一週以上
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25/100
Issue 類型
功能
描述清晰度
需要釐清
活躍度
停滯
技術堆疊
flask, python
領域
tooling

研究方向

先在 airflow/www/views.py:850 重現 reveal_type 的結果，以及第 115 行附近的 TYPE_CHECKING 嘗試。檢視 Flask's flask.globals 的型別和 stubgen 如何處理第三方屬性。完成的標準是：該 issue 具有一種有文件記錄且可維護的方法，或具有一個範圍明確的 type-checker 功能，能在不提供完整替代 stub 的情況下為這類屬性加上型別。

由索引模型根據 Issue 內容生成。

描述

feature

Feature

I would like to be able to add a (typed) attribute to a third-party class instance.

To give a specific example, Flask's current_app, and Flask-AppBuilder. Some example code:

    def my_view(self):
        reveal_type(current_app.appbuilder)
        if current_app.appbuilder.sm.has_access(...):
            ...

The reveal_type here shows Any: airflow/www/views.py:850: note: Revealed type is 'Any'

Things I tried:

  1. To add a typed attribute myself:

    if TYPE_CHECKING:
    current_app.appbuilder = AppBuilder(None)
    reveal_type(current_app.appbuilder)

    Didn't work: airflow/www/views.py:115: note: Revealed type is 'Any'

  2. A partial type stub file

    I could use stubgen etc to create a stub file for all of flask and then edit the type in flask.globals, but this presents a maintenance burden that I don't want (keeping it in sync).

    I searched for any way I could to have a "partial" stub file -- if I could have a stubs/flask/globals.pyi with out neededing all the rest of the type stubs for this module, but couldn't get it working - likely not supported.

Pitch

I don't know what the feature would look like, but for the flask ecosystem it is fairly common to add properties on to the global flask object, or the g global variable, and I would love to be able to type-check my use of them, without needing to cast it at each use.

This issue is mostly a request for help/ "is there any sensible way of doing this?"

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Python
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