jashkenas/coffeescript

Bug: Wrong `this` in bound methods of nested classes

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#5,222 建立於 2019年7月18日

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 (1 留言) (5 反應) (0 負責人)CoffeeScript (16,577 star) (1,980 fork)batch import
bughelp wanted

描述

While upgrading an application to CS2 we ran into the following issue in an obscure usage of nested classes.

Screenshot 2019-07-18 at 16 33 10

As you can see, the nested bound method thought its this is the parent class. This seems to happen on a "parse" level, because it's replaced in the code. This lead to tricky to catch bug on our side.

貢獻者指南

技術棧
javascript
領域
tooling
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-2 days
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
needs investigation
前置要求
CoffeeScript class syntaxJavaScript 'this' bindingbasic understanding of compilation
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
25
研究方向
Investigate the CoffeeScript parser, specifically how bound methods in nested classes are compiled. Look at the relevant source files such as 'src/nodes.coffee' or 'src/grammar.coffee' to understand how 'this' is resolved. Check if there are any existing tests for nested class bound methods. Consider reproducing the issue with a minimal example and examining the generated JavaScript output to identify where the binding goes wrong.