jashkenas/coffeescript

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

Open

#5,222 创建于 2019年7月18日

在 GitHub 查看
 (1 评论) (5 反应) (0 负责人)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.

贡献者指南

技术栈
javascript
领域
tooling
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-2 days
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
needs investigation
前置要求
CoffeeScript class syntaxJavaScript 'this' bindingbasic understanding of compilation
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
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.