capitalized-comments' ignorePattern should default to no-fallthrough's commentPattern

Tell us about your environment

• ESLint Version: 5.2.0
• Node Version: v8.9.4
• npm Version: 5.6.0

What parser (default, Babel-ESLint, etc.) are you using? default

Please show your full configuration:

Configuration

{
    "env": {
        "browser": true,
        "es6": true,
        "greasemonkey": true
    },
    "extends": "eslint:recommended",
    "globals": {
        "player": false,
        "PLAYER_STATE": false
    },
    "rules": {
        "no-fallthrough": [
            "error", {
                "commentPattern": "fall\\-through"
            }
        ],
        "capitalized-comments": "error"
    }
}

What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.

var playerState = player.getPlayerState();

switch (playerState) {
    case PLAYER_STATE.Unstarted: // fall-through
    case PLAYER_STATE.Ended: // fall-through
    case PLAYER_STATE.Paused: // fall-through
    case PLAYER_STATE.Buffering: // fall-through
    case PLAYER_STATE.VideoCued: {
        player.playVideo();

        break;
    }
}

eslint scripts/**/*

What did you expect to happen?

capitalized-comments should have been loaded the ignorePattern (that I didn’t set) from the no-fallthrough’s commentPattern option, as it’s clear I’d be using that fall through pattern.

What actually happened? Please include the actual, raw output from ESLint.

.../scripts/Main/main.js
  4:34  error  Comments should not begin with a lowercase character  capitalized-comments
  5:30  error  Comments should not begin with a lowercase character  capitalized-comments
  6:31  error  Comments should not begin with a lowercase character  capitalized-comments
  7:34  error  Comments should not begin with a lowercase character  capitalized-comments

[not-an-aardvark]

No worries – I just meant that it’s hard for me to predict how ESLint will change in the distant future.

Yes, I’ll go ahead and close it. We definitely appreciate you creating the issue!

To avoid duplication in your config, one option would be to use an .eslintrc.js file and use variables:

const FALL_THROUGH_PATTERN = "fall\\-through";

module.exports = {
    "rules": {
        "no-fallthrough": [
            "error", {
                "commentPattern": FALL_THROUGH_PATTERN
            }
        ],
        "capitalized-comments": [
            "error",
            "always", {
                "ignorePattern": FALL_THROUGH_PATTERN
            }
        ],
        "line-comment-position": [
            "error", {
                "position": "above",
                "ignorePattern": FALL_THROUGH_PATTERN
            }
        ]
    }
};

[kaicataldo]

Hi, thanks for the issue. ESLint rules can’t know about each other by design, so this is not something capitalized-comments can do. A solution for this is to use the capitalized-comments rule’s ignorePattern option:

/* eslint capitalized-comments: ["error", "always", { "ignorePattern": "fall-through" }] */

I don’t think adding a case by default for the no-fallthrough comment is desirable here for two reasons:

1. The pattern can be changed
2. If someone isn’t using no-fallthrough, the capitalized-comments rule could be ignoring comments it shouldn’t be

Edit: Typo, meant to type no-fallthrough comment.