Adding comments to JavaScript file causes Atom to hang.

[cbarrick]

I'm on Atom 0.92.0 with Language Javascript 0.24.0. The issue doesn't happen with this plugin disabled. No logs in the dev console or Console.app that I can find.

There is a thread on the forums: http://discuss.atom.io/t/bug-adding-comment-to-javascript-file-crashes-atom/6786

Steps to reproduce:

1. Take the source below.
2. Put the cursor at the very beginning
3. Press return
4. Press up
5. Press /

   Expected:

A "/" character should be entered on a new line at the top of the document

Actual:

Atom hangs.

Sample source:

/// The parser's job is to read some source and extract the markdown. The hard part of the parsing
/// is handled by a packrat parser generated from `grammar/docparser.peg`. This module wraps the
/// parser to provide a higher-level interface.

var docparser = require('../grammar/docparser');

docparser.Parser.DocBlock = {
    isDocBlock: true,

    // Extracts the markdown from the node.
    getDocs: function () {
        var docs = '';
        this.elements.forEach(function (line) {
            docs += line.docs.textValue;
        })
        return docs;
    }
}

/// `parse(source)`
/// --------------------------------------------------
/// **TODO**: Summary
///
/// ### Arguments
/// 1. `source` *(String)*: The source code to parse.
///
/// ### Returns
/// *(Array of Strings)*: The blocks of markdown documentation in the source.

exports.parse = function (source) {
    var ast = docparser.parse(source);
    var docs = [];
    ast.elements.forEach(function (block) {
        if (block.isDocBlock) {
            docs.push(block.getDocs());
        }
    })
    return docs;
}

[ChrisJefferson]

The bug is I believe an interaction between

"end": "(?!\\G)",

in "punctuation.whitespace.comment.leading.js".

and the 'punctuation.definition.string.begin.js' rule:

"begin": "(?<=[=(:]|^|return|&&|\\|\\||!)\\s*(/)(?![/*+{}?])"

As editing either of these seems to fix matters.

You can read http://textmate.1073791.n5.nabble.com/The-use-of-G-in-single-line-comments-td25933.html for a discussion of how this rule operates in textmate.

Now, I'm not really sure what these rules are doing to be honest

[ChrisJefferson]

Ignoring the fact that, as I say, I don't know what I'm doing, if I change the definition of punctuation.definition.string.begin.js begin from the current value to (so just changing the ?![ into ?=/[^), so:

   "begin": "(?<=[=(:]|^|return|&&|\\|\\||!)\\s*(/)(?=/[^/*+{}?])"

That seems to fix the problem. I copied that from textmate's current javascript bundle.

[kevinsawicki]

This looks to have been fixed by https://github.com/atom/language-javascript/commit/212b6ada88179ad41fcf9e4eba04ef6ce74eff31 so I'm going to close this out here, sorry for the delay, but it should be fixed in the latest Atom release, 0.125

[baelter]

I'm experiencing this on 0.178.0

Toggling comments via editor:toggle-line-comments works fine but adding or removing comments manually hangs atom. Only in js files.

[50Wliu]

Can you reproduce this in safe mode (atom --safe)?

[baelter]

No I can not reproduce in --safe. It is the compilation of suggestion list that hangs atom.

[baelter]

Sorry, not exclusive to javascript. Just observed the same bug in ruby.

[izuzak]

@baelter Sounds like a possible problem in autocomplete-plus (since you're not able to reproduce the problem in safe mode). Have you reported the issue over there as well? If so, can you add a link here for reference? Thanks.