jashkenas/coffeescript

Bug: Heregex escaped space before comment includes comment in transpiled regex

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#5,428 opened on Oct 13, 2022

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 (0 comments) (0 reactions) (0 assignees)CoffeeScript (16,577 stars) (1,980 forks)batch import
bughelp wanted

Description

Input Code

///
a\ # this is a bug
///

Expected Behavior

// this is a bug
/a /;

Current Behavior

// this is a bug
/a #thisisabug/;
  • CoffeeScript version: 2.7.0

Contributor guide

Tech stack
None
Domain
backend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
CoffeeScript basicsregex parsing concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Investigate the CoffeeScript compiler's heregex parsing logic. The bug is that an escaped space before a comment causes the comment to be included in the regex. Look at the code that handles whitespace and comments within heregexes. Possibly modify the lexer or parser to correctly ignore comments after escaped spaces. Files like `src/lexer.coffee` or `src/regex.coffee` might be relevant.